From 3f6ace84a3f7e06ccede49fe2fa112ab14f6b392 Mon Sep 17 00:00:00 2001
From: Adam Pocock <adam.pocock@oracle.com>
Date: Tue, 13 Sep 2022 12:23:37 -0400
Subject: [PATCH 1/7] Roughing out tree protos.

---
 .../main/resources/protos/tribuo-tree.proto   | 71 +++++++++++++++++++
 .../protos/tribuo-regression-tree.proto       | 49 +++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 Common/Trees/src/main/resources/protos/tribuo-tree.proto
 create mode 100644 Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto

diff --git a/Common/Trees/src/main/resources/protos/tribuo-tree.proto b/Common/Trees/src/main/resources/protos/tribuo-tree.proto
new file mode 100644
index 000000000..d89c93a5e
--- /dev/null
+++ b/Common/Trees/src/main/resources/protos/tribuo-tree.proto
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+syntax = "proto3";
+
+/*
+ * Protos for serializing Tribuo trees.
+ */
+package tribuo.tree;
+
+option java_multiple_files = true;
+option java_package = "org.tribuo.common.tree.protos";
+
+// We use any to encode polymorphism
+import "google/protobuf/any.proto";
+
+// Import Tribuo's core protos
+import "tribuo-core.proto";
+
+/**
+Tree Node proto
+ */
+message TreeNodeProto {
+  int32 version = 1;
+  string class_name = 2;
+  google.protobuf.Any serialized_data = 3;
+}
+
+/*
+SplitNode proto
+ */
+message SplitNodeProto {
+  int32 parent_idx = 1;
+  int32 greater_than_idx = 2;
+  int32 less_than_or_equal_idx = 3;
+  int32 split_feature_idx = 4;
+  double split_value = 5;
+  double impurity = 6;
+}
+
+/*
+LeafNode proto
+ */
+message LeafNodeProto {
+  int32 parent_idx = 1;
+  double impurity = 2;
+  tribuo.core.OutputProto output = 3;
+  map<string,tribuo.core.OutputProto> score = 4;
+  bool generates_probabilities = 5;
+}
+
+/*
+TreeModel proto
+ */
+message TreeModelProto {
+  tribuo.core.ModelDataProto metadata = 1;
+  repeated TreeNodeProto nodes = 2;
+}
diff --git a/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto b/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto
new file mode 100644
index 000000000..16cc280bd
--- /dev/null
+++ b/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+syntax = "proto3";
+
+/*
+ * Protos for serializing Tribuo regression trees.
+ */
+package tribuo.regression.tree;
+
+option java_multiple_files = true;
+option java_package = "org.tribuo.regression.tree.protos";
+
+// We use any to encode polymorphism
+import "google/protobuf/any.proto";
+
+// Import Tribuo's core protos
+import "tribuo-core.proto";
+
+// Import Tribuo's tree protos
+import "tribuo-tree.proto";
+
+/*
+Carrier for a list of tree nodes.
+ */
+message TreeNodeListProto {
+  repeated TreeNodeProto nodes = 3;
+}
+
+/*
+IndependentRegressionTreeModel proto
+ */
+message IndependentRegressionTreeModelProto {
+  tribuo.core.ModelDataProto metadata = 1;
+  map<string,TreeNodeListProto> nodes = 2;
+}
\ No newline at end of file

From 46a5cc96293b9bf2bb06dd00984e9f22c11ed2b2 Mon Sep 17 00:00:00 2001
From: Adam Pocock <adam.pocock@oracle.com>
Date: Wed, 14 Sep 2022 15:23:32 -0400
Subject: [PATCH 2/7] Filling out tree serialization. Still missing the main
 TreeModel serialize method.

---
 .../tribuo/classification/dtree/TestCART.java |    3 +-
 .../java/org/tribuo/common/tree/LeafNode.java |  107 ++
 .../java/org/tribuo/common/tree/Node.java     |    3 +-
 .../org/tribuo/common/tree/SplitNode.java     |  120 ++
 .../org/tribuo/common/tree/TreeModel.java     |  166 ++-
 .../common/tree/protos/LeafNodeProto.java     | 1163 +++++++++++++++++
 .../tree/protos/LeafNodeProtoOrBuilder.java   |   82 ++
 .../common/tree/protos/SplitNodeProto.java    |  879 +++++++++++++
 .../tree/protos/SplitNodeProtoOrBuilder.java  |   51 +
 .../common/tree/protos/TreeModelProto.java    |  966 ++++++++++++++
 .../tree/protos/TreeModelProtoOrBuilder.java  |   48 +
 .../common/tree/protos/TreeNodeProto.java     |  819 ++++++++++++
 .../tree/protos/TreeNodeProtoOrBuilder.java   |   42 +
 .../tribuo/common/tree/protos/TribuoTree.java |  114 ++
 .../main/resources/protos/tribuo-tree.proto   |   22 +-
 .../rtree/IndependentRegressionTreeModel.java |   78 +-
 .../IndependentRegressionTreeModelProto.java  |  904 +++++++++++++
 ...dentRegressionTreeModelProtoOrBuilder.java |   58 +
 .../rtree/protos/TreeNodeListProto.java       |  778 +++++++++++
 .../protos/TreeNodeListProtoOrBuilder.java    |   33 +
 .../rtree/protos/TribuoRegressionTree.java    |   83 ++
 .../protos/tribuo-regression-tree.proto       |    7 +-
 .../rtree/TestCARTJointRegressionTrainer.java |    4 +-
 .../rtree/TestCARTRegressionTrainer.java      |    4 +-
 24 files changed, 6510 insertions(+), 24 deletions(-)
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProto.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProtoOrBuilder.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProto.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProtoOrBuilder.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProto.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProtoOrBuilder.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProto.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProtoOrBuilder.java
 create mode 100644 Common/Trees/src/main/java/org/tribuo/common/tree/protos/TribuoTree.java
 create mode 100644 Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProto.java
 create mode 100644 Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProtoOrBuilder.java
 create mode 100644 Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProto.java
 create mode 100644 Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProtoOrBuilder.java
 create mode 100644 Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TribuoRegressionTree.java

diff --git a/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java b/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java
index 5f21db086..347491aaa 100644
--- a/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java
+++ b/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -54,6 +54,7 @@ public static Model<Label> testCART(Pair<Dataset<Label>,Dataset<Label>> p, CARTC
         features = m.getTopFeatures(-1);
         Assertions.assertNotNull(features);
         Assertions.assertFalse(features.isEmpty());
+        Helpers.testModelProtoSerialization(m, Label.class, p.getB());
 
         return m;
     }
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/LeafNode.java b/Common/Trees/src/main/java/org/tribuo/common/tree/LeafNode.java
index ea351ead9..28744de49 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/LeafNode.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/LeafNode.java
@@ -16,10 +16,14 @@
 
 package org.tribuo.common.tree;
 
+import com.google.protobuf.Any;
 import org.tribuo.Example;
 import org.tribuo.Output;
 import org.tribuo.Prediction;
+import org.tribuo.common.tree.protos.LeafNodeProto;
+import org.tribuo.common.tree.protos.TreeNodeProto;
 import org.tribuo.math.la.SparseVector;
+import org.tribuo.protos.core.OutputProto;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -35,6 +39,11 @@
 public class LeafNode<T extends Output<T>> implements Node<T> {
     private static final long serialVersionUID = 4L;
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     private final double impurity;
 
     private final T output;
@@ -136,4 +145,102 @@ public String toString() {
         return "LeafNode(impurity="+impurity+",output="+output.toString()+",scores="+scores.toString()+",probability="+generatesProbabilities+")";
     }
 
+    TreeNodeProto serialize(int parentIdx, int curIdx) {
+        LeafNodeProto.Builder nodeBuilder = LeafNodeProto.newBuilder();
+        nodeBuilder.setParentIdx(parentIdx);
+        nodeBuilder.setCurIdx(curIdx);
+        nodeBuilder.setOutput(output.serialize());
+        for (Map.Entry<String, T> e : scores.entrySet()) {
+            nodeBuilder.putScore(e.getKey(), e.getValue().serialize());
+        }
+        nodeBuilder.setGeneratesProbabilities(generatesProbabilities);
+        nodeBuilder.setImpurity(impurity);
+
+
+        TreeNodeProto.Builder builder = TreeNodeProto.newBuilder();
+        builder.setVersion(CURRENT_VERSION);
+        builder.setClassName(LeafNode.class.getName());
+        builder.setSerializedData(Any.pack(nodeBuilder.build()));
+
+        return builder.build();
+    }
+
+    static final class LeafNodeBuilder<T extends Output<T>> extends TreeModel.NodeBuilder implements Node<T> {
+        private final int parentIdx;
+        private final int curIdx;
+        private final double impurity;
+        private final T output;
+        private final Map<String,T> scores;
+        private final boolean generatesProbabilities;
+
+        @SuppressWarnings("unchecked")
+        LeafNodeBuilder(LeafNodeProto proto) {
+            this.parentIdx = proto.getParentIdx();
+            this.curIdx = proto.getCurIdx();
+            this.impurity = proto.getImpurity();
+            this.output = (T) Output.deserialize(proto.getOutput());
+            this.scores = new HashMap<>();
+            for (Map.Entry<String, OutputProto> e : proto.getScoreMap().entrySet()) {
+                Output<?> curOutput = Output.deserialize(e.getValue());
+                if (!curOutput.getClass().equals(output.getClass())) {
+                    throw new IllegalStateException("Invalid protobuf, scores were not the same type as the most likely output, found " + curOutput.getClass() + ", expected " + output.getClass());
+                }
+                this.scores.put(e.getKey(), (T) curOutput);
+            }
+            this.generatesProbabilities = proto.getGeneratesProbabilities();
+        }
+
+        LeafNodeBuilder(int parentIdx, int curIdx, double impurity, T output, Map<String, T> scores, boolean generatesProbabilities) {
+            this.parentIdx = parentIdx;
+            this.curIdx = curIdx;
+            this.impurity = impurity;
+            this.output = output;
+            this.scores = scores;
+            this.generatesProbabilities = generatesProbabilities;
+        }
+
+        @Override
+        public boolean isLeaf() {
+            return true;
+        }
+
+        @Override
+        public Node<T> getNextNode(SparseVector example) {
+            return null;
+        }
+
+        @Override
+        public double getImpurity() {
+            return impurity;
+        }
+
+        @Override
+        public LeafNodeBuilder<T> copy() {
+            return new LeafNodeBuilder<>(parentIdx,curIdx,impurity,output.copy(),new HashMap<>(scores),generatesProbabilities);
+        }
+
+        /**
+         * Gets the index of the parent node.
+         * @return The parent index.
+         */
+        int getParentIdx() {
+            return parentIdx;
+        }
+
+        /**
+         * Gets the index of this node.
+         * @return The current node index.
+         */
+        int getCurIdx() {
+            return curIdx;
+        }
+
+        /**
+         * Builds this builder into a leaf node.
+         * @return The leaf node.
+         */
+        LeafNode<T> build() {
+            return new LeafNode<>(impurity,output.copy(),new HashMap<>(scores),generatesProbabilities);
+        }
+    }
 }
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/Node.java b/Common/Trees/src/main/java/org/tribuo/common/tree/Node.java
index cfb9bc59e..41bd50a04 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/Node.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/Node.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -50,5 +50,4 @@ public interface Node<T extends Output<T>> extends Serializable {
      * @return A deep copy.
      */
     public Node<T> copy();
-
 }
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java b/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
index 4b214591c..2ad55a1a2 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
@@ -16,7 +16,10 @@
 
 package org.tribuo.common.tree;
 
+import com.google.protobuf.Any;
 import org.tribuo.Output;
+import org.tribuo.common.tree.protos.SplitNodeProto;
+import org.tribuo.common.tree.protos.TreeNodeProto;
 import org.tribuo.math.la.SparseVector;
 
 import java.util.Objects;
@@ -27,6 +30,11 @@
 public class SplitNode<T extends Output<T>> implements Node<T> {
     private static final long serialVersionUID = 3L;
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     private final Node<T> greaterThan;
 
     private final Node<T> lessThanOrEqual;
@@ -138,5 +146,117 @@ public boolean equals(Object o) {
     public int hashCode() {
         return Objects.hash(greaterThan, lessThanOrEqual, splitFeature, splitValue, impurity);
     }
+
+    TreeNodeProto serialize(int parentIdx, int curIdx, int greaterThanIdx, int lessThanOrEqualIdx) {
+        SplitNodeProto.Builder nodeBuilder = SplitNodeProto.newBuilder();
+        nodeBuilder.setParentIdx(parentIdx);
+        nodeBuilder.setCurIdx(curIdx);
+        nodeBuilder.setGreaterThanIdx(greaterThanIdx);
+        nodeBuilder.setLessThanOrEqualIdx(lessThanOrEqualIdx);
+        nodeBuilder.setSplitFeatureIdx(splitFeature);
+        nodeBuilder.setSplitValue(splitValue);
+        nodeBuilder.setImpurity(impurity);
+
+        TreeNodeProto.Builder builder = TreeNodeProto.newBuilder();
+        builder.setVersion(CURRENT_VERSION);
+        builder.setClassName(LeafNode.class.getName());
+        builder.setSerializedData(Any.pack(nodeBuilder.build()));
+
+        return builder.build();
+    }
+
+    static final class SplitNodeBuilder<T extends Output<T>> extends TreeModel.NodeBuilder implements Node<T> {
+
+        private final int parentIdx;
+        private final int curIdx;
+        private final int greaterThanIdx;
+        private final int lessThanOrEqualIdx;
+        private final int splitFeature;
+        private final double splitValue;
+        private final double impurity;
+
+        private Node<T> greaterThan;
+        private Node<T> lessThanOrEqual;
+
+        SplitNodeBuilder(SplitNodeProto proto) {
+            this.parentIdx = proto.getParentIdx();
+            this.curIdx = proto.getCurIdx();
+            this.greaterThanIdx = proto.getGreaterThanIdx();
+            this.lessThanOrEqualIdx = proto.getLessThanOrEqualIdx();
+            this.splitFeature = proto.getSplitFeatureIdx();
+            this.splitValue = proto.getSplitValue();
+            this.impurity = proto.getImpurity();
+        }
+
+        SplitNodeBuilder(int parentIdx, int curIdx, int greaterThanIdx, int lessThanOrEqualIdx, int splitFeature, double splitValue, double impurity) {
+            this.parentIdx = parentIdx;
+            this.curIdx = curIdx;
+            this.greaterThanIdx = greaterThanIdx;
+            this.lessThanOrEqualIdx = lessThanOrEqualIdx;
+            this.splitFeature = splitFeature;
+            this.splitValue = splitValue;
+            this.impurity = impurity;
+        }
+
+        @Override
+        public boolean isLeaf() {
+            return false;
+        }
+
+        @Override
+        public Node<T> getNextNode(SparseVector example) {
+            return null;
+        }
+
+        @Override
+        public double getImpurity() {
+            return impurity;
+        }
+
+        @Override
+        public SplitNodeBuilder<T> copy() {
+            return new SplitNodeBuilder<>(parentIdx, curIdx, greaterThanIdx, lessThanOrEqualIdx, splitFeature, splitValue, impurity);
+        }
+
+        boolean canBuild() {
+            return greaterThan != null && lessThanOrEqual != null;
+        }
+
+        SplitNode<T> build() {
+            return new SplitNode<>(splitValue,splitFeature,impurity,greaterThan,lessThanOrEqual);
+        }
+
+        void setGreaterThan(Node<T> greaterThan) {
+            if (this.greaterThan == null) {
+                this.greaterThan = greaterThan;
+            } else {
+                throw new IllegalStateException("Invalid protobuf, multiple nodes mapped to the greaterThanIdx");
+            }
+        }
+
+        void setLessThanOrEqualIdx(Node<T> lessThanOrEqual) {
+            if (this.lessThanOrEqual == null) {
+                this.lessThanOrEqual = lessThanOrEqual;
+            } else {
+                throw new IllegalStateException("Invalid protobuf, multiple nodes mapped to the lessThanOrEqualIdx");
+            }
+        }
+
+        int getGreaterThanIdx() {
+            return greaterThanIdx;
+        }
+
+        int getLessThanOrEqualIdx() {
+            return lessThanOrEqualIdx;
+        }
+
+        int getParentIdx() {
+            return parentIdx;
+        }
+
+        int getCurIdx() {
+            return curIdx;
+        }
+    }
 }
 
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
index af14628f4..e7a029188 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@
 
 package org.tribuo.common.tree;
 
+import com.google.protobuf.Any;
+import com.google.protobuf.InvalidProtocolBufferException;
 import com.oracle.labs.mlrg.olcut.util.Pair;
 import org.tribuo.Example;
 import org.tribuo.Excuse;
@@ -25,9 +27,18 @@
 import org.tribuo.Output;
 import org.tribuo.Prediction;
 import org.tribuo.SparseModel;
+import org.tribuo.common.tree.protos.LeafNodeProto;
+import org.tribuo.common.tree.protos.SplitNodeProto;
+import org.tribuo.common.tree.protos.TreeModelProto;
+import org.tribuo.common.tree.protos.TreeNodeProto;
+import org.tribuo.impl.ModelDataCarrier;
+import org.tribuo.math.la.DenseSparseMatrix;
 import org.tribuo.math.la.SparseVector;
+import org.tribuo.math.la.Tensor;
+import org.tribuo.protos.core.ModelProto;
 import org.tribuo.provenance.ModelProvenance;
 
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -48,6 +59,11 @@
 public class TreeModel<T extends Output<T>> extends SparseModel<T> {
     private static final long serialVersionUID = 3L;
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     private final Node<T> root;
 
     /**
@@ -83,6 +99,127 @@ protected TreeModel(String name, ModelProvenance description,
         this.root = null;
     }
 
+    /**
+     * Deserialization factory.
+     * @param version The serialized object version.
+     * @param className The class name.
+     * @param message The serialized data.
+     */
+    @SuppressWarnings({"unchecked","rawtypes"}) // guarded by getClass to ensure all the output types are the same.
+    public static TreeModel<?> deserializeFromProto(int version, String className, Any message) throws InvalidProtocolBufferException {
+        if (version < 0 || version > CURRENT_VERSION) {
+            throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + CURRENT_VERSION);
+        }
+        TreeModelProto proto = message.unpack(TreeModelProto.class);
+
+        ModelDataCarrier<?> carrier = ModelDataCarrier.deserialize(proto.getMetadata());
+        Class<?> outputClass = carrier.outputDomain().getOutput(0).getClass();
+
+        if (proto.getNodesCount() == 0) {
+            throw new IllegalStateException("Invalid protobuf, tree must contain nodes");
+        }
+
+        List<TreeNodeProto> nodeProtos = proto.getNodesList();
+        List<Node<?>> nodes = deserializeFromProtos(nodeProtos, (Class) outputClass);
+
+        return new TreeModel(carrier.name(),carrier.provenance(),carrier.featureDomain(),carrier.outputDomain(),carrier.generatesProbabilities(),nodes.get(0));
+    }
+
+    private static Node<?> deserializeNodeProto(TreeNodeProto proto) throws InvalidProtocolBufferException {
+        int version = proto.getVersion();
+        String className = proto.getClassName();
+        Any message = proto.getSerializedData();
+        String type = message.getTypeUrl();
+        if (type.equals(SplitNodeProto.getDescriptor().getFullName())) {
+            SplitNodeProto splitProto = message.unpack(SplitNodeProto.class);
+            return new SplitNode.SplitNodeBuilder<>(splitProto);
+        } else if (type.equals(LeafNodeProto.getDescriptor().getFullName())) {
+            LeafNodeProto leafProto = message.unpack(LeafNodeProto.class);
+            return new LeafNode.LeafNodeBuilder<>(leafProto);
+        } else {
+            throw new IllegalStateException("Invalid protobuf, expected leaf or split node, found " + type);
+        }
+    }
+
+    /**
+     * Deserializes a list of node protos into a list of nodes, with the root in the first element.
+     * @param nodeProtos The node protos to deserialize.
+     * @return The nodes.
+     * @throws InvalidProtocolBufferException If an unexpected proto is found.
+     */
+    //@SuppressWarnings({"unchecked","rawtypes"}) // guarded by getClass to ensure all the output types are the same.
+    protected static <U extends Output<U>> List<Node<U>> deserializeFromProtos(List<TreeNodeProto> nodeProtos, Class<U> outputClass) throws InvalidProtocolBufferException {
+        List<Node<U>> nodes = new ArrayList<>(nodeProtos.size());
+
+        for (TreeNodeProto p : nodeProtos) {
+            @SuppressWarnings("unchecked") // we'll catch this later with the getClass check
+            Node<U> curNode = (Node<U>) deserializeNodeProto(p);
+            nodes.add(curNode);
+        }
+
+        Queue<Node<U>> nodeQueue = new ArrayDeque<>();
+        for (Node<U> node : nodes) {
+            if (node instanceof LeafNode.LeafNodeBuilder) {
+                nodeQueue.offer(node);
+            }
+        }
+
+        while (!nodeQueue.isEmpty()) {
+            Node<U> node = nodeQueue.poll();
+            int parentIdx = -1;
+            Node<U> parent = null;
+            Node<U> builtNode = null;
+            if (node instanceof LeafNode.LeafNodeBuilder) {
+                // build leaf node
+                LeafNode.LeafNodeBuilder<U> builder = (LeafNode.LeafNodeBuilder<U>) node;
+                LeafNode<U> leaf = builder.build();
+                nodes.set(builder.getCurIdx(), leaf);
+                builtNode = leaf;
+                // update parent
+                parentIdx = builder.getParentIdx();
+                parent = nodes.get(parentIdx);
+            } else if (node instanceof SplitNode.SplitNodeBuilder) {
+                SplitNode.SplitNodeBuilder<U> builder = (SplitNode.SplitNodeBuilder<U>) node;
+                SplitNode<U> split = builder.build();
+                nodes.set(builder.getCurIdx(), split);
+                builtNode = split;
+                parentIdx = builder.getParentIdx();
+                if (parentIdx != -1) {
+                    parent = nodes.get(parentIdx);
+                }
+            }
+            if (parent instanceof SplitNode.SplitNodeBuilder) {
+                SplitNode.SplitNodeBuilder<U> splitBuilder = (SplitNode.SplitNodeBuilder<U>) parent;
+                if (parentIdx == splitBuilder.getGreaterThanIdx()) {
+                    splitBuilder.setGreaterThan(builtNode);
+                } else if (parentIdx == splitBuilder.getLessThanOrEqualIdx()) {
+                    splitBuilder.setLessThanOrEqualIdx(builtNode);
+                } else {
+                    throw new IllegalStateException("Invalid protobuf, found a child node which didn't map into a parent");
+                }
+                // If we can build this split node pop it on the queue.
+                if (splitBuilder.canBuild()) {
+                    nodeQueue.offer(splitBuilder);
+                }
+            } else if (parent != null) {
+                throw new IllegalStateException("Invalid protobuf, found a " + parent.getClass() + " when a SplitNodeBuilder was expected");
+            }
+        }
+
+        for (Node<U> node : nodes) {
+            if (!(node instanceof SplitNode || node instanceof LeafNode)) {
+                throw new IllegalStateException("Invalid protobuf, found unbuilt node, " + node);
+            } else if (node instanceof LeafNode) {
+                U cur = ((LeafNode<U>) node).getOutput();
+                if (!cur.getClass().equals(outputClass)) {
+                    throw new IllegalStateException("Invalid protobuf, node output did not match output domain, found " + cur.getClass() + ", expected " + outputClass);
+                }
+            }
+        }
+
+        return nodes;
+    }
+
     private static <T extends Output<T>> Map<String,List<String>> gatherActiveFeatures(ImmutableFeatureMap fMap, Node<T> root) {
         Set<String> activeFeatures = new LinkedHashSet<>();
 
@@ -287,4 +424,31 @@ public Node<T> getRoot() {
         return root;
     }
 
+    @Override
+    public ModelProto serialize() {
+        ModelDataCarrier<T> carrier = createDataCarrier();
+
+        TreeModelProto.Builder modelBuilder = TreeModelProto.newBuilder();
+        modelBuilder.setMetadata(carrier.serialize());
+        modelBuilder.addAllNodes(serializeToNodes(root));
+
+        ModelProto.Builder builder = ModelProto.newBuilder();
+        builder.setSerializedData(Any.pack(modelBuilder.build()));
+        builder.setClassName(TreeModel.class.getName());
+        builder.setVersion(CURRENT_VERSION);
+
+        return builder.build();
+    }
+
+    protected List<TreeNodeProto> serializeToNodes(Node<T> root) {
+        List<TreeNodeProto> protos = new ArrayList<>();
+
+        return protos;
+    }
+
+    static abstract class NodeBuilder {
+        abstract int getParentIdx();
+        abstract int getCurIdx();
+        abstract Node<?> build();
+    }
 }
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProto.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProto.java
new file mode 100644
index 000000000..cf5e5d323
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProto.java
@@ -0,0 +1,1163 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+/**
+ * <pre>
+ *LeafNode proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.tree.LeafNodeProto}
+ */
+public final class LeafNodeProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.tree.LeafNodeProto)
+    LeafNodeProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use LeafNodeProto.newBuilder() to construct.
+  private LeafNodeProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private LeafNodeProto() {
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new LeafNodeProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private LeafNodeProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    int mutable_bitField0_ = 0;
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 8: {
+
+            parentIdx_ = input.readInt32();
+            break;
+          }
+          case 16: {
+
+            curIdx_ = input.readInt32();
+            break;
+          }
+          case 25: {
+
+            impurity_ = input.readDouble();
+            break;
+          }
+          case 34: {
+            org.tribuo.protos.core.OutputProto.Builder subBuilder = null;
+            if (output_ != null) {
+              subBuilder = output_.toBuilder();
+            }
+            output_ = input.readMessage(org.tribuo.protos.core.OutputProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(output_);
+              output_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 42: {
+            if (!((mutable_bitField0_ & 0x00000001) != 0)) {
+              score_ = com.google.protobuf.MapField.newMapField(
+                  ScoreDefaultEntryHolder.defaultEntry);
+              mutable_bitField0_ |= 0x00000001;
+            }
+            com.google.protobuf.MapEntry<java.lang.String, org.tribuo.protos.core.OutputProto>
+            score__ = input.readMessage(
+                ScoreDefaultEntryHolder.defaultEntry.getParserForType(), extensionRegistry);
+            score_.getMutableMap().put(
+                score__.getKey(), score__.getValue());
+            break;
+          }
+          case 48: {
+
+            generatesProbabilities_ = input.readBool();
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_LeafNodeProto_descriptor;
+  }
+
+  @SuppressWarnings({"rawtypes"})
+  @java.lang.Override
+  protected com.google.protobuf.MapField internalGetMapField(
+      int number) {
+    switch (number) {
+      case 5:
+        return internalGetScore();
+      default:
+        throw new RuntimeException(
+            "Invalid map field number: " + number);
+    }
+  }
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_LeafNodeProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.tree.protos.LeafNodeProto.class, org.tribuo.common.tree.protos.LeafNodeProto.Builder.class);
+  }
+
+  public static final int PARENT_IDX_FIELD_NUMBER = 1;
+  private int parentIdx_;
+  /**
+   * <code>int32 parent_idx = 1;</code>
+   * @return The parentIdx.
+   */
+  @java.lang.Override
+  public int getParentIdx() {
+    return parentIdx_;
+  }
+
+  public static final int CUR_IDX_FIELD_NUMBER = 2;
+  private int curIdx_;
+  /**
+   * <code>int32 cur_idx = 2;</code>
+   * @return The curIdx.
+   */
+  @java.lang.Override
+  public int getCurIdx() {
+    return curIdx_;
+  }
+
+  public static final int IMPURITY_FIELD_NUMBER = 3;
+  private double impurity_;
+  /**
+   * <code>double impurity = 3;</code>
+   * @return The impurity.
+   */
+  @java.lang.Override
+  public double getImpurity() {
+    return impurity_;
+  }
+
+  public static final int OUTPUT_FIELD_NUMBER = 4;
+  private org.tribuo.protos.core.OutputProto output_;
+  /**
+   * <code>.tribuo.core.OutputProto output = 4;</code>
+   * @return Whether the output field is set.
+   */
+  @java.lang.Override
+  public boolean hasOutput() {
+    return output_ != null;
+  }
+  /**
+   * <code>.tribuo.core.OutputProto output = 4;</code>
+   * @return The output.
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.OutputProto getOutput() {
+    return output_ == null ? org.tribuo.protos.core.OutputProto.getDefaultInstance() : output_;
+  }
+  /**
+   * <code>.tribuo.core.OutputProto output = 4;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.OutputProtoOrBuilder getOutputOrBuilder() {
+    return getOutput();
+  }
+
+  public static final int SCORE_FIELD_NUMBER = 5;
+  private static final class ScoreDefaultEntryHolder {
+    static final com.google.protobuf.MapEntry<
+        java.lang.String, org.tribuo.protos.core.OutputProto> defaultEntry =
+            com.google.protobuf.MapEntry
+            .<java.lang.String, org.tribuo.protos.core.OutputProto>newDefaultInstance(
+                org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_LeafNodeProto_ScoreEntry_descriptor, 
+                com.google.protobuf.WireFormat.FieldType.STRING,
+                "",
+                com.google.protobuf.WireFormat.FieldType.MESSAGE,
+                org.tribuo.protos.core.OutputProto.getDefaultInstance());
+  }
+  private com.google.protobuf.MapField<
+      java.lang.String, org.tribuo.protos.core.OutputProto> score_;
+  private com.google.protobuf.MapField<java.lang.String, org.tribuo.protos.core.OutputProto>
+  internalGetScore() {
+    if (score_ == null) {
+      return com.google.protobuf.MapField.emptyMapField(
+          ScoreDefaultEntryHolder.defaultEntry);
+    }
+    return score_;
+  }
+
+  public int getScoreCount() {
+    return internalGetScore().getMap().size();
+  }
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+
+  @java.lang.Override
+  public boolean containsScore(
+      java.lang.String key) {
+    if (key == null) { throw new NullPointerException("map key"); }
+    return internalGetScore().getMap().containsKey(key);
+  }
+  /**
+   * Use {@link #getScoreMap()} instead.
+   */
+  @java.lang.Override
+  @java.lang.Deprecated
+  public java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> getScore() {
+    return getScoreMap();
+  }
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+  @java.lang.Override
+
+  public java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> getScoreMap() {
+    return internalGetScore().getMap();
+  }
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+  @java.lang.Override
+
+  public org.tribuo.protos.core.OutputProto getScoreOrDefault(
+      java.lang.String key,
+      org.tribuo.protos.core.OutputProto defaultValue) {
+    if (key == null) { throw new NullPointerException("map key"); }
+    java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> map =
+        internalGetScore().getMap();
+    return map.containsKey(key) ? map.get(key) : defaultValue;
+  }
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+  @java.lang.Override
+
+  public org.tribuo.protos.core.OutputProto getScoreOrThrow(
+      java.lang.String key) {
+    if (key == null) { throw new NullPointerException("map key"); }
+    java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> map =
+        internalGetScore().getMap();
+    if (!map.containsKey(key)) {
+      throw new java.lang.IllegalArgumentException();
+    }
+    return map.get(key);
+  }
+
+  public static final int GENERATES_PROBABILITIES_FIELD_NUMBER = 6;
+  private boolean generatesProbabilities_;
+  /**
+   * <code>bool generates_probabilities = 6;</code>
+   * @return The generatesProbabilities.
+   */
+  @java.lang.Override
+  public boolean getGeneratesProbabilities() {
+    return generatesProbabilities_;
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (parentIdx_ != 0) {
+      output.writeInt32(1, parentIdx_);
+    }
+    if (curIdx_ != 0) {
+      output.writeInt32(2, curIdx_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(impurity_) != 0) {
+      output.writeDouble(3, impurity_);
+    }
+    if (output_ != null) {
+      output.writeMessage(4, getOutput());
+    }
+    com.google.protobuf.GeneratedMessageV3
+      .serializeStringMapTo(
+        output,
+        internalGetScore(),
+        ScoreDefaultEntryHolder.defaultEntry,
+        5);
+    if (generatesProbabilities_ != false) {
+      output.writeBool(6, generatesProbabilities_);
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (parentIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(1, parentIdx_);
+    }
+    if (curIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(2, curIdx_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(impurity_) != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeDoubleSize(3, impurity_);
+    }
+    if (output_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(4, getOutput());
+    }
+    for (java.util.Map.Entry<java.lang.String, org.tribuo.protos.core.OutputProto> entry
+         : internalGetScore().getMap().entrySet()) {
+      com.google.protobuf.MapEntry<java.lang.String, org.tribuo.protos.core.OutputProto>
+      score__ = ScoreDefaultEntryHolder.defaultEntry.newBuilderForType()
+          .setKey(entry.getKey())
+          .setValue(entry.getValue())
+          .build();
+      size += com.google.protobuf.CodedOutputStream
+          .computeMessageSize(5, score__);
+    }
+    if (generatesProbabilities_ != false) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeBoolSize(6, generatesProbabilities_);
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.tree.protos.LeafNodeProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.tree.protos.LeafNodeProto other = (org.tribuo.common.tree.protos.LeafNodeProto) obj;
+
+    if (getParentIdx()
+        != other.getParentIdx()) return false;
+    if (getCurIdx()
+        != other.getCurIdx()) return false;
+    if (java.lang.Double.doubleToLongBits(getImpurity())
+        != java.lang.Double.doubleToLongBits(
+            other.getImpurity())) return false;
+    if (hasOutput() != other.hasOutput()) return false;
+    if (hasOutput()) {
+      if (!getOutput()
+          .equals(other.getOutput())) return false;
+    }
+    if (!internalGetScore().equals(
+        other.internalGetScore())) return false;
+    if (getGeneratesProbabilities()
+        != other.getGeneratesProbabilities()) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + PARENT_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getParentIdx();
+    hash = (37 * hash) + CUR_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getCurIdx();
+    hash = (37 * hash) + IMPURITY_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashLong(
+        java.lang.Double.doubleToLongBits(getImpurity()));
+    if (hasOutput()) {
+      hash = (37 * hash) + OUTPUT_FIELD_NUMBER;
+      hash = (53 * hash) + getOutput().hashCode();
+    }
+    if (!internalGetScore().getMap().isEmpty()) {
+      hash = (37 * hash) + SCORE_FIELD_NUMBER;
+      hash = (53 * hash) + internalGetScore().hashCode();
+    }
+    hash = (37 * hash) + GENERATES_PROBABILITIES_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashBoolean(
+        getGeneratesProbabilities());
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.LeafNodeProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.tree.protos.LeafNodeProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *LeafNode proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.tree.LeafNodeProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.tree.LeafNodeProto)
+      org.tribuo.common.tree.protos.LeafNodeProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_LeafNodeProto_descriptor;
+    }
+
+    @SuppressWarnings({"rawtypes"})
+    protected com.google.protobuf.MapField internalGetMapField(
+        int number) {
+      switch (number) {
+        case 5:
+          return internalGetScore();
+        default:
+          throw new RuntimeException(
+              "Invalid map field number: " + number);
+      }
+    }
+    @SuppressWarnings({"rawtypes"})
+    protected com.google.protobuf.MapField internalGetMutableMapField(
+        int number) {
+      switch (number) {
+        case 5:
+          return internalGetMutableScore();
+        default:
+          throw new RuntimeException(
+              "Invalid map field number: " + number);
+      }
+    }
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_LeafNodeProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.tree.protos.LeafNodeProto.class, org.tribuo.common.tree.protos.LeafNodeProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.tree.protos.LeafNodeProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      parentIdx_ = 0;
+
+      curIdx_ = 0;
+
+      impurity_ = 0D;
+
+      if (outputBuilder_ == null) {
+        output_ = null;
+      } else {
+        output_ = null;
+        outputBuilder_ = null;
+      }
+      internalGetMutableScore().clear();
+      generatesProbabilities_ = false;
+
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_LeafNodeProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.LeafNodeProto getDefaultInstanceForType() {
+      return org.tribuo.common.tree.protos.LeafNodeProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.LeafNodeProto build() {
+      org.tribuo.common.tree.protos.LeafNodeProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.LeafNodeProto buildPartial() {
+      org.tribuo.common.tree.protos.LeafNodeProto result = new org.tribuo.common.tree.protos.LeafNodeProto(this);
+      int from_bitField0_ = bitField0_;
+      result.parentIdx_ = parentIdx_;
+      result.curIdx_ = curIdx_;
+      result.impurity_ = impurity_;
+      if (outputBuilder_ == null) {
+        result.output_ = output_;
+      } else {
+        result.output_ = outputBuilder_.build();
+      }
+      result.score_ = internalGetScore();
+      result.score_.makeImmutable();
+      result.generatesProbabilities_ = generatesProbabilities_;
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.tree.protos.LeafNodeProto) {
+        return mergeFrom((org.tribuo.common.tree.protos.LeafNodeProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.tree.protos.LeafNodeProto other) {
+      if (other == org.tribuo.common.tree.protos.LeafNodeProto.getDefaultInstance()) return this;
+      if (other.getParentIdx() != 0) {
+        setParentIdx(other.getParentIdx());
+      }
+      if (other.getCurIdx() != 0) {
+        setCurIdx(other.getCurIdx());
+      }
+      if (other.getImpurity() != 0D) {
+        setImpurity(other.getImpurity());
+      }
+      if (other.hasOutput()) {
+        mergeOutput(other.getOutput());
+      }
+      internalGetMutableScore().mergeFrom(
+          other.internalGetScore());
+      if (other.getGeneratesProbabilities() != false) {
+        setGeneratesProbabilities(other.getGeneratesProbabilities());
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.tree.protos.LeafNodeProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.tree.protos.LeafNodeProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+    private int bitField0_;
+
+    private int parentIdx_ ;
+    /**
+     * <code>int32 parent_idx = 1;</code>
+     * @return The parentIdx.
+     */
+    @java.lang.Override
+    public int getParentIdx() {
+      return parentIdx_;
+    }
+    /**
+     * <code>int32 parent_idx = 1;</code>
+     * @param value The parentIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setParentIdx(int value) {
+      
+      parentIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 parent_idx = 1;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearParentIdx() {
+      
+      parentIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private int curIdx_ ;
+    /**
+     * <code>int32 cur_idx = 2;</code>
+     * @return The curIdx.
+     */
+    @java.lang.Override
+    public int getCurIdx() {
+      return curIdx_;
+    }
+    /**
+     * <code>int32 cur_idx = 2;</code>
+     * @param value The curIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setCurIdx(int value) {
+      
+      curIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 cur_idx = 2;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearCurIdx() {
+      
+      curIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private double impurity_ ;
+    /**
+     * <code>double impurity = 3;</code>
+     * @return The impurity.
+     */
+    @java.lang.Override
+    public double getImpurity() {
+      return impurity_;
+    }
+    /**
+     * <code>double impurity = 3;</code>
+     * @param value The impurity to set.
+     * @return This builder for chaining.
+     */
+    public Builder setImpurity(double value) {
+      
+      impurity_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>double impurity = 3;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearImpurity() {
+      
+      impurity_ = 0D;
+      onChanged();
+      return this;
+    }
+
+    private org.tribuo.protos.core.OutputProto output_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.OutputProto, org.tribuo.protos.core.OutputProto.Builder, org.tribuo.protos.core.OutputProtoOrBuilder> outputBuilder_;
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     * @return Whether the output field is set.
+     */
+    public boolean hasOutput() {
+      return outputBuilder_ != null || output_ != null;
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     * @return The output.
+     */
+    public org.tribuo.protos.core.OutputProto getOutput() {
+      if (outputBuilder_ == null) {
+        return output_ == null ? org.tribuo.protos.core.OutputProto.getDefaultInstance() : output_;
+      } else {
+        return outputBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    public Builder setOutput(org.tribuo.protos.core.OutputProto value) {
+      if (outputBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        output_ = value;
+        onChanged();
+      } else {
+        outputBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    public Builder setOutput(
+        org.tribuo.protos.core.OutputProto.Builder builderForValue) {
+      if (outputBuilder_ == null) {
+        output_ = builderForValue.build();
+        onChanged();
+      } else {
+        outputBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    public Builder mergeOutput(org.tribuo.protos.core.OutputProto value) {
+      if (outputBuilder_ == null) {
+        if (output_ != null) {
+          output_ =
+            org.tribuo.protos.core.OutputProto.newBuilder(output_).mergeFrom(value).buildPartial();
+        } else {
+          output_ = value;
+        }
+        onChanged();
+      } else {
+        outputBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    public Builder clearOutput() {
+      if (outputBuilder_ == null) {
+        output_ = null;
+        onChanged();
+      } else {
+        output_ = null;
+        outputBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    public org.tribuo.protos.core.OutputProto.Builder getOutputBuilder() {
+      
+      onChanged();
+      return getOutputFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    public org.tribuo.protos.core.OutputProtoOrBuilder getOutputOrBuilder() {
+      if (outputBuilder_ != null) {
+        return outputBuilder_.getMessageOrBuilder();
+      } else {
+        return output_ == null ?
+            org.tribuo.protos.core.OutputProto.getDefaultInstance() : output_;
+      }
+    }
+    /**
+     * <code>.tribuo.core.OutputProto output = 4;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.OutputProto, org.tribuo.protos.core.OutputProto.Builder, org.tribuo.protos.core.OutputProtoOrBuilder> 
+        getOutputFieldBuilder() {
+      if (outputBuilder_ == null) {
+        outputBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.protos.core.OutputProto, org.tribuo.protos.core.OutputProto.Builder, org.tribuo.protos.core.OutputProtoOrBuilder>(
+                getOutput(),
+                getParentForChildren(),
+                isClean());
+        output_ = null;
+      }
+      return outputBuilder_;
+    }
+
+    private com.google.protobuf.MapField<
+        java.lang.String, org.tribuo.protos.core.OutputProto> score_;
+    private com.google.protobuf.MapField<java.lang.String, org.tribuo.protos.core.OutputProto>
+    internalGetScore() {
+      if (score_ == null) {
+        return com.google.protobuf.MapField.emptyMapField(
+            ScoreDefaultEntryHolder.defaultEntry);
+      }
+      return score_;
+    }
+    private com.google.protobuf.MapField<java.lang.String, org.tribuo.protos.core.OutputProto>
+    internalGetMutableScore() {
+      onChanged();;
+      if (score_ == null) {
+        score_ = com.google.protobuf.MapField.newMapField(
+            ScoreDefaultEntryHolder.defaultEntry);
+      }
+      if (!score_.isMutable()) {
+        score_ = score_.copy();
+      }
+      return score_;
+    }
+
+    public int getScoreCount() {
+      return internalGetScore().getMap().size();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+
+    @java.lang.Override
+    public boolean containsScore(
+        java.lang.String key) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      return internalGetScore().getMap().containsKey(key);
+    }
+    /**
+     * Use {@link #getScoreMap()} instead.
+     */
+    @java.lang.Override
+    @java.lang.Deprecated
+    public java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> getScore() {
+      return getScoreMap();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+    @java.lang.Override
+
+    public java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> getScoreMap() {
+      return internalGetScore().getMap();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+    @java.lang.Override
+
+    public org.tribuo.protos.core.OutputProto getScoreOrDefault(
+        java.lang.String key,
+        org.tribuo.protos.core.OutputProto defaultValue) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> map =
+          internalGetScore().getMap();
+      return map.containsKey(key) ? map.get(key) : defaultValue;
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+    @java.lang.Override
+
+    public org.tribuo.protos.core.OutputProto getScoreOrThrow(
+        java.lang.String key) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> map =
+          internalGetScore().getMap();
+      if (!map.containsKey(key)) {
+        throw new java.lang.IllegalArgumentException();
+      }
+      return map.get(key);
+    }
+
+    public Builder clearScore() {
+      internalGetMutableScore().getMutableMap()
+          .clear();
+      return this;
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+
+    public Builder removeScore(
+        java.lang.String key) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      internalGetMutableScore().getMutableMap()
+          .remove(key);
+      return this;
+    }
+    /**
+     * Use alternate mutation accessors instead.
+     */
+    @java.lang.Deprecated
+    public java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto>
+    getMutableScore() {
+      return internalGetMutableScore().getMutableMap();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+    public Builder putScore(
+        java.lang.String key,
+        org.tribuo.protos.core.OutputProto value) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      if (value == null) {
+  throw new NullPointerException("map value");
+}
+
+      internalGetMutableScore().getMutableMap()
+          .put(key, value);
+      return this;
+    }
+    /**
+     * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+     */
+
+    public Builder putAllScore(
+        java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto> values) {
+      internalGetMutableScore().getMutableMap()
+          .putAll(values);
+      return this;
+    }
+
+    private boolean generatesProbabilities_ ;
+    /**
+     * <code>bool generates_probabilities = 6;</code>
+     * @return The generatesProbabilities.
+     */
+    @java.lang.Override
+    public boolean getGeneratesProbabilities() {
+      return generatesProbabilities_;
+    }
+    /**
+     * <code>bool generates_probabilities = 6;</code>
+     * @param value The generatesProbabilities to set.
+     * @return This builder for chaining.
+     */
+    public Builder setGeneratesProbabilities(boolean value) {
+      
+      generatesProbabilities_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>bool generates_probabilities = 6;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearGeneratesProbabilities() {
+      
+      generatesProbabilities_ = false;
+      onChanged();
+      return this;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.tree.LeafNodeProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.tree.LeafNodeProto)
+  private static final org.tribuo.common.tree.protos.LeafNodeProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.tree.protos.LeafNodeProto();
+  }
+
+  public static org.tribuo.common.tree.protos.LeafNodeProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<LeafNodeProto>
+      PARSER = new com.google.protobuf.AbstractParser<LeafNodeProto>() {
+    @java.lang.Override
+    public LeafNodeProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new LeafNodeProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<LeafNodeProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<LeafNodeProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.LeafNodeProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProtoOrBuilder.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProtoOrBuilder.java
new file mode 100644
index 000000000..8cdb9c98a
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/LeafNodeProtoOrBuilder.java
@@ -0,0 +1,82 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+public interface LeafNodeProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.tree.LeafNodeProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>int32 parent_idx = 1;</code>
+   * @return The parentIdx.
+   */
+  int getParentIdx();
+
+  /**
+   * <code>int32 cur_idx = 2;</code>
+   * @return The curIdx.
+   */
+  int getCurIdx();
+
+  /**
+   * <code>double impurity = 3;</code>
+   * @return The impurity.
+   */
+  double getImpurity();
+
+  /**
+   * <code>.tribuo.core.OutputProto output = 4;</code>
+   * @return Whether the output field is set.
+   */
+  boolean hasOutput();
+  /**
+   * <code>.tribuo.core.OutputProto output = 4;</code>
+   * @return The output.
+   */
+  org.tribuo.protos.core.OutputProto getOutput();
+  /**
+   * <code>.tribuo.core.OutputProto output = 4;</code>
+   */
+  org.tribuo.protos.core.OutputProtoOrBuilder getOutputOrBuilder();
+
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+  int getScoreCount();
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+  boolean containsScore(
+      java.lang.String key);
+  /**
+   * Use {@link #getScoreMap()} instead.
+   */
+  @java.lang.Deprecated
+  java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto>
+  getScore();
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+  java.util.Map<java.lang.String, org.tribuo.protos.core.OutputProto>
+  getScoreMap();
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+
+  org.tribuo.protos.core.OutputProto getScoreOrDefault(
+      java.lang.String key,
+      org.tribuo.protos.core.OutputProto defaultValue);
+  /**
+   * <code>map&lt;string, .tribuo.core.OutputProto&gt; score = 5;</code>
+   */
+
+  org.tribuo.protos.core.OutputProto getScoreOrThrow(
+      java.lang.String key);
+
+  /**
+   * <code>bool generates_probabilities = 6;</code>
+   * @return The generatesProbabilities.
+   */
+  boolean getGeneratesProbabilities();
+}
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProto.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProto.java
new file mode 100644
index 000000000..0dfa94ded
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProto.java
@@ -0,0 +1,879 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+/**
+ * <pre>
+ *SplitNode proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.tree.SplitNodeProto}
+ */
+public final class SplitNodeProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.tree.SplitNodeProto)
+    SplitNodeProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use SplitNodeProto.newBuilder() to construct.
+  private SplitNodeProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private SplitNodeProto() {
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new SplitNodeProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private SplitNodeProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 8: {
+
+            parentIdx_ = input.readInt32();
+            break;
+          }
+          case 16: {
+
+            curIdx_ = input.readInt32();
+            break;
+          }
+          case 24: {
+
+            greaterThanIdx_ = input.readInt32();
+            break;
+          }
+          case 32: {
+
+            lessThanOrEqualIdx_ = input.readInt32();
+            break;
+          }
+          case 40: {
+
+            splitFeatureIdx_ = input.readInt32();
+            break;
+          }
+          case 49: {
+
+            splitValue_ = input.readDouble();
+            break;
+          }
+          case 57: {
+
+            impurity_ = input.readDouble();
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_SplitNodeProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_SplitNodeProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.tree.protos.SplitNodeProto.class, org.tribuo.common.tree.protos.SplitNodeProto.Builder.class);
+  }
+
+  public static final int PARENT_IDX_FIELD_NUMBER = 1;
+  private int parentIdx_;
+  /**
+   * <code>int32 parent_idx = 1;</code>
+   * @return The parentIdx.
+   */
+  @java.lang.Override
+  public int getParentIdx() {
+    return parentIdx_;
+  }
+
+  public static final int CUR_IDX_FIELD_NUMBER = 2;
+  private int curIdx_;
+  /**
+   * <code>int32 cur_idx = 2;</code>
+   * @return The curIdx.
+   */
+  @java.lang.Override
+  public int getCurIdx() {
+    return curIdx_;
+  }
+
+  public static final int GREATER_THAN_IDX_FIELD_NUMBER = 3;
+  private int greaterThanIdx_;
+  /**
+   * <code>int32 greater_than_idx = 3;</code>
+   * @return The greaterThanIdx.
+   */
+  @java.lang.Override
+  public int getGreaterThanIdx() {
+    return greaterThanIdx_;
+  }
+
+  public static final int LESS_THAN_OR_EQUAL_IDX_FIELD_NUMBER = 4;
+  private int lessThanOrEqualIdx_;
+  /**
+   * <code>int32 less_than_or_equal_idx = 4;</code>
+   * @return The lessThanOrEqualIdx.
+   */
+  @java.lang.Override
+  public int getLessThanOrEqualIdx() {
+    return lessThanOrEqualIdx_;
+  }
+
+  public static final int SPLIT_FEATURE_IDX_FIELD_NUMBER = 5;
+  private int splitFeatureIdx_;
+  /**
+   * <code>int32 split_feature_idx = 5;</code>
+   * @return The splitFeatureIdx.
+   */
+  @java.lang.Override
+  public int getSplitFeatureIdx() {
+    return splitFeatureIdx_;
+  }
+
+  public static final int SPLIT_VALUE_FIELD_NUMBER = 6;
+  private double splitValue_;
+  /**
+   * <code>double split_value = 6;</code>
+   * @return The splitValue.
+   */
+  @java.lang.Override
+  public double getSplitValue() {
+    return splitValue_;
+  }
+
+  public static final int IMPURITY_FIELD_NUMBER = 7;
+  private double impurity_;
+  /**
+   * <code>double impurity = 7;</code>
+   * @return The impurity.
+   */
+  @java.lang.Override
+  public double getImpurity() {
+    return impurity_;
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (parentIdx_ != 0) {
+      output.writeInt32(1, parentIdx_);
+    }
+    if (curIdx_ != 0) {
+      output.writeInt32(2, curIdx_);
+    }
+    if (greaterThanIdx_ != 0) {
+      output.writeInt32(3, greaterThanIdx_);
+    }
+    if (lessThanOrEqualIdx_ != 0) {
+      output.writeInt32(4, lessThanOrEqualIdx_);
+    }
+    if (splitFeatureIdx_ != 0) {
+      output.writeInt32(5, splitFeatureIdx_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(splitValue_) != 0) {
+      output.writeDouble(6, splitValue_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(impurity_) != 0) {
+      output.writeDouble(7, impurity_);
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (parentIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(1, parentIdx_);
+    }
+    if (curIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(2, curIdx_);
+    }
+    if (greaterThanIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(3, greaterThanIdx_);
+    }
+    if (lessThanOrEqualIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(4, lessThanOrEqualIdx_);
+    }
+    if (splitFeatureIdx_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(5, splitFeatureIdx_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(splitValue_) != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeDoubleSize(6, splitValue_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(impurity_) != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeDoubleSize(7, impurity_);
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.tree.protos.SplitNodeProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.tree.protos.SplitNodeProto other = (org.tribuo.common.tree.protos.SplitNodeProto) obj;
+
+    if (getParentIdx()
+        != other.getParentIdx()) return false;
+    if (getCurIdx()
+        != other.getCurIdx()) return false;
+    if (getGreaterThanIdx()
+        != other.getGreaterThanIdx()) return false;
+    if (getLessThanOrEqualIdx()
+        != other.getLessThanOrEqualIdx()) return false;
+    if (getSplitFeatureIdx()
+        != other.getSplitFeatureIdx()) return false;
+    if (java.lang.Double.doubleToLongBits(getSplitValue())
+        != java.lang.Double.doubleToLongBits(
+            other.getSplitValue())) return false;
+    if (java.lang.Double.doubleToLongBits(getImpurity())
+        != java.lang.Double.doubleToLongBits(
+            other.getImpurity())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + PARENT_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getParentIdx();
+    hash = (37 * hash) + CUR_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getCurIdx();
+    hash = (37 * hash) + GREATER_THAN_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getGreaterThanIdx();
+    hash = (37 * hash) + LESS_THAN_OR_EQUAL_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getLessThanOrEqualIdx();
+    hash = (37 * hash) + SPLIT_FEATURE_IDX_FIELD_NUMBER;
+    hash = (53 * hash) + getSplitFeatureIdx();
+    hash = (37 * hash) + SPLIT_VALUE_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashLong(
+        java.lang.Double.doubleToLongBits(getSplitValue()));
+    hash = (37 * hash) + IMPURITY_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashLong(
+        java.lang.Double.doubleToLongBits(getImpurity()));
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.SplitNodeProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.tree.protos.SplitNodeProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *SplitNode proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.tree.SplitNodeProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.tree.SplitNodeProto)
+      org.tribuo.common.tree.protos.SplitNodeProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_SplitNodeProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_SplitNodeProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.tree.protos.SplitNodeProto.class, org.tribuo.common.tree.protos.SplitNodeProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.tree.protos.SplitNodeProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      parentIdx_ = 0;
+
+      curIdx_ = 0;
+
+      greaterThanIdx_ = 0;
+
+      lessThanOrEqualIdx_ = 0;
+
+      splitFeatureIdx_ = 0;
+
+      splitValue_ = 0D;
+
+      impurity_ = 0D;
+
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_SplitNodeProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.SplitNodeProto getDefaultInstanceForType() {
+      return org.tribuo.common.tree.protos.SplitNodeProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.SplitNodeProto build() {
+      org.tribuo.common.tree.protos.SplitNodeProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.SplitNodeProto buildPartial() {
+      org.tribuo.common.tree.protos.SplitNodeProto result = new org.tribuo.common.tree.protos.SplitNodeProto(this);
+      result.parentIdx_ = parentIdx_;
+      result.curIdx_ = curIdx_;
+      result.greaterThanIdx_ = greaterThanIdx_;
+      result.lessThanOrEqualIdx_ = lessThanOrEqualIdx_;
+      result.splitFeatureIdx_ = splitFeatureIdx_;
+      result.splitValue_ = splitValue_;
+      result.impurity_ = impurity_;
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.tree.protos.SplitNodeProto) {
+        return mergeFrom((org.tribuo.common.tree.protos.SplitNodeProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.tree.protos.SplitNodeProto other) {
+      if (other == org.tribuo.common.tree.protos.SplitNodeProto.getDefaultInstance()) return this;
+      if (other.getParentIdx() != 0) {
+        setParentIdx(other.getParentIdx());
+      }
+      if (other.getCurIdx() != 0) {
+        setCurIdx(other.getCurIdx());
+      }
+      if (other.getGreaterThanIdx() != 0) {
+        setGreaterThanIdx(other.getGreaterThanIdx());
+      }
+      if (other.getLessThanOrEqualIdx() != 0) {
+        setLessThanOrEqualIdx(other.getLessThanOrEqualIdx());
+      }
+      if (other.getSplitFeatureIdx() != 0) {
+        setSplitFeatureIdx(other.getSplitFeatureIdx());
+      }
+      if (other.getSplitValue() != 0D) {
+        setSplitValue(other.getSplitValue());
+      }
+      if (other.getImpurity() != 0D) {
+        setImpurity(other.getImpurity());
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.tree.protos.SplitNodeProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.tree.protos.SplitNodeProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+
+    private int parentIdx_ ;
+    /**
+     * <code>int32 parent_idx = 1;</code>
+     * @return The parentIdx.
+     */
+    @java.lang.Override
+    public int getParentIdx() {
+      return parentIdx_;
+    }
+    /**
+     * <code>int32 parent_idx = 1;</code>
+     * @param value The parentIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setParentIdx(int value) {
+      
+      parentIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 parent_idx = 1;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearParentIdx() {
+      
+      parentIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private int curIdx_ ;
+    /**
+     * <code>int32 cur_idx = 2;</code>
+     * @return The curIdx.
+     */
+    @java.lang.Override
+    public int getCurIdx() {
+      return curIdx_;
+    }
+    /**
+     * <code>int32 cur_idx = 2;</code>
+     * @param value The curIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setCurIdx(int value) {
+      
+      curIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 cur_idx = 2;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearCurIdx() {
+      
+      curIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private int greaterThanIdx_ ;
+    /**
+     * <code>int32 greater_than_idx = 3;</code>
+     * @return The greaterThanIdx.
+     */
+    @java.lang.Override
+    public int getGreaterThanIdx() {
+      return greaterThanIdx_;
+    }
+    /**
+     * <code>int32 greater_than_idx = 3;</code>
+     * @param value The greaterThanIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setGreaterThanIdx(int value) {
+      
+      greaterThanIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 greater_than_idx = 3;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearGreaterThanIdx() {
+      
+      greaterThanIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private int lessThanOrEqualIdx_ ;
+    /**
+     * <code>int32 less_than_or_equal_idx = 4;</code>
+     * @return The lessThanOrEqualIdx.
+     */
+    @java.lang.Override
+    public int getLessThanOrEqualIdx() {
+      return lessThanOrEqualIdx_;
+    }
+    /**
+     * <code>int32 less_than_or_equal_idx = 4;</code>
+     * @param value The lessThanOrEqualIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setLessThanOrEqualIdx(int value) {
+      
+      lessThanOrEqualIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 less_than_or_equal_idx = 4;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearLessThanOrEqualIdx() {
+      
+      lessThanOrEqualIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private int splitFeatureIdx_ ;
+    /**
+     * <code>int32 split_feature_idx = 5;</code>
+     * @return The splitFeatureIdx.
+     */
+    @java.lang.Override
+    public int getSplitFeatureIdx() {
+      return splitFeatureIdx_;
+    }
+    /**
+     * <code>int32 split_feature_idx = 5;</code>
+     * @param value The splitFeatureIdx to set.
+     * @return This builder for chaining.
+     */
+    public Builder setSplitFeatureIdx(int value) {
+      
+      splitFeatureIdx_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 split_feature_idx = 5;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearSplitFeatureIdx() {
+      
+      splitFeatureIdx_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private double splitValue_ ;
+    /**
+     * <code>double split_value = 6;</code>
+     * @return The splitValue.
+     */
+    @java.lang.Override
+    public double getSplitValue() {
+      return splitValue_;
+    }
+    /**
+     * <code>double split_value = 6;</code>
+     * @param value The splitValue to set.
+     * @return This builder for chaining.
+     */
+    public Builder setSplitValue(double value) {
+      
+      splitValue_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>double split_value = 6;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearSplitValue() {
+      
+      splitValue_ = 0D;
+      onChanged();
+      return this;
+    }
+
+    private double impurity_ ;
+    /**
+     * <code>double impurity = 7;</code>
+     * @return The impurity.
+     */
+    @java.lang.Override
+    public double getImpurity() {
+      return impurity_;
+    }
+    /**
+     * <code>double impurity = 7;</code>
+     * @param value The impurity to set.
+     * @return This builder for chaining.
+     */
+    public Builder setImpurity(double value) {
+      
+      impurity_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>double impurity = 7;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearImpurity() {
+      
+      impurity_ = 0D;
+      onChanged();
+      return this;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.tree.SplitNodeProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.tree.SplitNodeProto)
+  private static final org.tribuo.common.tree.protos.SplitNodeProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.tree.protos.SplitNodeProto();
+  }
+
+  public static org.tribuo.common.tree.protos.SplitNodeProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<SplitNodeProto>
+      PARSER = new com.google.protobuf.AbstractParser<SplitNodeProto>() {
+    @java.lang.Override
+    public SplitNodeProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new SplitNodeProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<SplitNodeProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<SplitNodeProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.SplitNodeProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProtoOrBuilder.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProtoOrBuilder.java
new file mode 100644
index 000000000..6e225938b
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/SplitNodeProtoOrBuilder.java
@@ -0,0 +1,51 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+public interface SplitNodeProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.tree.SplitNodeProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>int32 parent_idx = 1;</code>
+   * @return The parentIdx.
+   */
+  int getParentIdx();
+
+  /**
+   * <code>int32 cur_idx = 2;</code>
+   * @return The curIdx.
+   */
+  int getCurIdx();
+
+  /**
+   * <code>int32 greater_than_idx = 3;</code>
+   * @return The greaterThanIdx.
+   */
+  int getGreaterThanIdx();
+
+  /**
+   * <code>int32 less_than_or_equal_idx = 4;</code>
+   * @return The lessThanOrEqualIdx.
+   */
+  int getLessThanOrEqualIdx();
+
+  /**
+   * <code>int32 split_feature_idx = 5;</code>
+   * @return The splitFeatureIdx.
+   */
+  int getSplitFeatureIdx();
+
+  /**
+   * <code>double split_value = 6;</code>
+   * @return The splitValue.
+   */
+  double getSplitValue();
+
+  /**
+   * <code>double impurity = 7;</code>
+   * @return The impurity.
+   */
+  double getImpurity();
+}
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProto.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProto.java
new file mode 100644
index 000000000..9b02171c6
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProto.java
@@ -0,0 +1,966 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+/**
+ * <pre>
+ *TreeModel proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.tree.TreeModelProto}
+ */
+public final class TreeModelProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.tree.TreeModelProto)
+    TreeModelProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use TreeModelProto.newBuilder() to construct.
+  private TreeModelProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private TreeModelProto() {
+    nodes_ = java.util.Collections.emptyList();
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new TreeModelProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private TreeModelProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    int mutable_bitField0_ = 0;
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 10: {
+            org.tribuo.protos.core.ModelDataProto.Builder subBuilder = null;
+            if (metadata_ != null) {
+              subBuilder = metadata_.toBuilder();
+            }
+            metadata_ = input.readMessage(org.tribuo.protos.core.ModelDataProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(metadata_);
+              metadata_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 18: {
+            if (!((mutable_bitField0_ & 0x00000001) != 0)) {
+              nodes_ = new java.util.ArrayList<org.tribuo.common.tree.protos.TreeNodeProto>();
+              mutable_bitField0_ |= 0x00000001;
+            }
+            nodes_.add(
+                input.readMessage(org.tribuo.common.tree.protos.TreeNodeProto.parser(), extensionRegistry));
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      if (((mutable_bitField0_ & 0x00000001) != 0)) {
+        nodes_ = java.util.Collections.unmodifiableList(nodes_);
+      }
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeModelProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeModelProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.tree.protos.TreeModelProto.class, org.tribuo.common.tree.protos.TreeModelProto.Builder.class);
+  }
+
+  public static final int METADATA_FIELD_NUMBER = 1;
+  private org.tribuo.protos.core.ModelDataProto metadata_;
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  @java.lang.Override
+  public boolean hasMetadata() {
+    return metadata_ != null;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProto getMetadata() {
+    return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+    return getMetadata();
+  }
+
+  public static final int NODES_FIELD_NUMBER = 2;
+  private java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> nodes_;
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  @java.lang.Override
+  public java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> getNodesList() {
+    return nodes_;
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  @java.lang.Override
+  public java.util.List<? extends org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+      getNodesOrBuilderList() {
+    return nodes_;
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  @java.lang.Override
+  public int getNodesCount() {
+    return nodes_.size();
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.TreeNodeProto getNodes(int index) {
+    return nodes_.get(index);
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder getNodesOrBuilder(
+      int index) {
+    return nodes_.get(index);
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (metadata_ != null) {
+      output.writeMessage(1, getMetadata());
+    }
+    for (int i = 0; i < nodes_.size(); i++) {
+      output.writeMessage(2, nodes_.get(i));
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (metadata_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(1, getMetadata());
+    }
+    for (int i = 0; i < nodes_.size(); i++) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(2, nodes_.get(i));
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.tree.protos.TreeModelProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.tree.protos.TreeModelProto other = (org.tribuo.common.tree.protos.TreeModelProto) obj;
+
+    if (hasMetadata() != other.hasMetadata()) return false;
+    if (hasMetadata()) {
+      if (!getMetadata()
+          .equals(other.getMetadata())) return false;
+    }
+    if (!getNodesList()
+        .equals(other.getNodesList())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    if (hasMetadata()) {
+      hash = (37 * hash) + METADATA_FIELD_NUMBER;
+      hash = (53 * hash) + getMetadata().hashCode();
+    }
+    if (getNodesCount() > 0) {
+      hash = (37 * hash) + NODES_FIELD_NUMBER;
+      hash = (53 * hash) + getNodesList().hashCode();
+    }
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.TreeModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.tree.protos.TreeModelProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *TreeModel proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.tree.TreeModelProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.tree.TreeModelProto)
+      org.tribuo.common.tree.protos.TreeModelProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeModelProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.tree.protos.TreeModelProto.class, org.tribuo.common.tree.protos.TreeModelProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.tree.protos.TreeModelProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+        getNodesFieldBuilder();
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+      if (nodesBuilder_ == null) {
+        nodes_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00000001);
+      } else {
+        nodesBuilder_.clear();
+      }
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.TreeModelProto getDefaultInstanceForType() {
+      return org.tribuo.common.tree.protos.TreeModelProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.TreeModelProto build() {
+      org.tribuo.common.tree.protos.TreeModelProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.TreeModelProto buildPartial() {
+      org.tribuo.common.tree.protos.TreeModelProto result = new org.tribuo.common.tree.protos.TreeModelProto(this);
+      int from_bitField0_ = bitField0_;
+      if (metadataBuilder_ == null) {
+        result.metadata_ = metadata_;
+      } else {
+        result.metadata_ = metadataBuilder_.build();
+      }
+      if (nodesBuilder_ == null) {
+        if (((bitField0_ & 0x00000001) != 0)) {
+          nodes_ = java.util.Collections.unmodifiableList(nodes_);
+          bitField0_ = (bitField0_ & ~0x00000001);
+        }
+        result.nodes_ = nodes_;
+      } else {
+        result.nodes_ = nodesBuilder_.build();
+      }
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.tree.protos.TreeModelProto) {
+        return mergeFrom((org.tribuo.common.tree.protos.TreeModelProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.tree.protos.TreeModelProto other) {
+      if (other == org.tribuo.common.tree.protos.TreeModelProto.getDefaultInstance()) return this;
+      if (other.hasMetadata()) {
+        mergeMetadata(other.getMetadata());
+      }
+      if (nodesBuilder_ == null) {
+        if (!other.nodes_.isEmpty()) {
+          if (nodes_.isEmpty()) {
+            nodes_ = other.nodes_;
+            bitField0_ = (bitField0_ & ~0x00000001);
+          } else {
+            ensureNodesIsMutable();
+            nodes_.addAll(other.nodes_);
+          }
+          onChanged();
+        }
+      } else {
+        if (!other.nodes_.isEmpty()) {
+          if (nodesBuilder_.isEmpty()) {
+            nodesBuilder_.dispose();
+            nodesBuilder_ = null;
+            nodes_ = other.nodes_;
+            bitField0_ = (bitField0_ & ~0x00000001);
+            nodesBuilder_ = 
+              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                 getNodesFieldBuilder() : null;
+          } else {
+            nodesBuilder_.addAllMessages(other.nodes_);
+          }
+        }
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.tree.protos.TreeModelProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.tree.protos.TreeModelProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+    private int bitField0_;
+
+    private org.tribuo.protos.core.ModelDataProto metadata_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> metadataBuilder_;
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return Whether the metadata field is set.
+     */
+    public boolean hasMetadata() {
+      return metadataBuilder_ != null || metadata_ != null;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return The metadata.
+     */
+    public org.tribuo.protos.core.ModelDataProto getMetadata() {
+      if (metadataBuilder_ == null) {
+        return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      } else {
+        return metadataBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        metadata_ = value;
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(
+        org.tribuo.protos.core.ModelDataProto.Builder builderForValue) {
+      if (metadataBuilder_ == null) {
+        metadata_ = builderForValue.build();
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder mergeMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (metadata_ != null) {
+          metadata_ =
+            org.tribuo.protos.core.ModelDataProto.newBuilder(metadata_).mergeFrom(value).buildPartial();
+        } else {
+          metadata_ = value;
+        }
+        onChanged();
+      } else {
+        metadataBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder clearMetadata() {
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+        onChanged();
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProto.Builder getMetadataBuilder() {
+      
+      onChanged();
+      return getMetadataFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+      if (metadataBuilder_ != null) {
+        return metadataBuilder_.getMessageOrBuilder();
+      } else {
+        return metadata_ == null ?
+            org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> 
+        getMetadataFieldBuilder() {
+      if (metadataBuilder_ == null) {
+        metadataBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder>(
+                getMetadata(),
+                getParentForChildren(),
+                isClean());
+        metadata_ = null;
+      }
+      return metadataBuilder_;
+    }
+
+    private java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> nodes_ =
+      java.util.Collections.emptyList();
+    private void ensureNodesIsMutable() {
+      if (!((bitField0_ & 0x00000001) != 0)) {
+        nodes_ = new java.util.ArrayList<org.tribuo.common.tree.protos.TreeNodeProto>(nodes_);
+        bitField0_ |= 0x00000001;
+       }
+    }
+
+    private com.google.protobuf.RepeatedFieldBuilderV3<
+        org.tribuo.common.tree.protos.TreeNodeProto, org.tribuo.common.tree.protos.TreeNodeProto.Builder, org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> nodesBuilder_;
+
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> getNodesList() {
+      if (nodesBuilder_ == null) {
+        return java.util.Collections.unmodifiableList(nodes_);
+      } else {
+        return nodesBuilder_.getMessageList();
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public int getNodesCount() {
+      if (nodesBuilder_ == null) {
+        return nodes_.size();
+      } else {
+        return nodesBuilder_.getCount();
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto getNodes(int index) {
+      if (nodesBuilder_ == null) {
+        return nodes_.get(index);
+      } else {
+        return nodesBuilder_.getMessage(index);
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder setNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto value) {
+      if (nodesBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureNodesIsMutable();
+        nodes_.set(index, value);
+        onChanged();
+      } else {
+        nodesBuilder_.setMessage(index, value);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder setNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto.Builder builderForValue) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.set(index, builderForValue.build());
+        onChanged();
+      } else {
+        nodesBuilder_.setMessage(index, builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder addNodes(org.tribuo.common.tree.protos.TreeNodeProto value) {
+      if (nodesBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureNodesIsMutable();
+        nodes_.add(value);
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(value);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder addNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto value) {
+      if (nodesBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureNodesIsMutable();
+        nodes_.add(index, value);
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(index, value);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder addNodes(
+        org.tribuo.common.tree.protos.TreeNodeProto.Builder builderForValue) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.add(builderForValue.build());
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder addNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto.Builder builderForValue) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.add(index, builderForValue.build());
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(index, builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder addAllNodes(
+        java.lang.Iterable<? extends org.tribuo.common.tree.protos.TreeNodeProto> values) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+            values, nodes_);
+        onChanged();
+      } else {
+        nodesBuilder_.addAllMessages(values);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder clearNodes() {
+      if (nodesBuilder_ == null) {
+        nodes_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00000001);
+        onChanged();
+      } else {
+        nodesBuilder_.clear();
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public Builder removeNodes(int index) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.remove(index);
+        onChanged();
+      } else {
+        nodesBuilder_.remove(index);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto.Builder getNodesBuilder(
+        int index) {
+      return getNodesFieldBuilder().getBuilder(index);
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder getNodesOrBuilder(
+        int index) {
+      if (nodesBuilder_ == null) {
+        return nodes_.get(index);  } else {
+        return nodesBuilder_.getMessageOrBuilder(index);
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public java.util.List<? extends org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+         getNodesOrBuilderList() {
+      if (nodesBuilder_ != null) {
+        return nodesBuilder_.getMessageOrBuilderList();
+      } else {
+        return java.util.Collections.unmodifiableList(nodes_);
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto.Builder addNodesBuilder() {
+      return getNodesFieldBuilder().addBuilder(
+          org.tribuo.common.tree.protos.TreeNodeProto.getDefaultInstance());
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto.Builder addNodesBuilder(
+        int index) {
+      return getNodesFieldBuilder().addBuilder(
+          index, org.tribuo.common.tree.protos.TreeNodeProto.getDefaultInstance());
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+     */
+    public java.util.List<org.tribuo.common.tree.protos.TreeNodeProto.Builder> 
+         getNodesBuilderList() {
+      return getNodesFieldBuilder().getBuilderList();
+    }
+    private com.google.protobuf.RepeatedFieldBuilderV3<
+        org.tribuo.common.tree.protos.TreeNodeProto, org.tribuo.common.tree.protos.TreeNodeProto.Builder, org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+        getNodesFieldBuilder() {
+      if (nodesBuilder_ == null) {
+        nodesBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
+            org.tribuo.common.tree.protos.TreeNodeProto, org.tribuo.common.tree.protos.TreeNodeProto.Builder, org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder>(
+                nodes_,
+                ((bitField0_ & 0x00000001) != 0),
+                getParentForChildren(),
+                isClean());
+        nodes_ = null;
+      }
+      return nodesBuilder_;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.tree.TreeModelProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.tree.TreeModelProto)
+  private static final org.tribuo.common.tree.protos.TreeModelProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.tree.protos.TreeModelProto();
+  }
+
+  public static org.tribuo.common.tree.protos.TreeModelProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<TreeModelProto>
+      PARSER = new com.google.protobuf.AbstractParser<TreeModelProto>() {
+    @java.lang.Override
+    public TreeModelProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new TreeModelProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<TreeModelProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<TreeModelProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.TreeModelProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProtoOrBuilder.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProtoOrBuilder.java
new file mode 100644
index 000000000..2fe098054
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeModelProtoOrBuilder.java
@@ -0,0 +1,48 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+public interface TreeModelProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.tree.TreeModelProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  boolean hasMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  org.tribuo.protos.core.ModelDataProto getMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder();
+
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> 
+      getNodesList();
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  org.tribuo.common.tree.protos.TreeNodeProto getNodes(int index);
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  int getNodesCount();
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  java.util.List<? extends org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+      getNodesOrBuilderList();
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 2;</code>
+   */
+  org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder getNodesOrBuilder(
+      int index);
+}
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProto.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProto.java
new file mode 100644
index 000000000..42088fe8d
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProto.java
@@ -0,0 +1,819 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+/**
+ * <pre>
+ **
+ *Tree Node proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.common.tree.TreeNodeProto}
+ */
+public final class TreeNodeProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.common.tree.TreeNodeProto)
+    TreeNodeProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use TreeNodeProto.newBuilder() to construct.
+  private TreeNodeProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private TreeNodeProto() {
+    className_ = "";
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new TreeNodeProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private TreeNodeProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 8: {
+
+            version_ = input.readInt32();
+            break;
+          }
+          case 18: {
+            java.lang.String s = input.readStringRequireUtf8();
+
+            className_ = s;
+            break;
+          }
+          case 26: {
+            com.google.protobuf.Any.Builder subBuilder = null;
+            if (serializedData_ != null) {
+              subBuilder = serializedData_.toBuilder();
+            }
+            serializedData_ = input.readMessage(com.google.protobuf.Any.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(serializedData_);
+              serializedData_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeNodeProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeNodeProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.common.tree.protos.TreeNodeProto.class, org.tribuo.common.tree.protos.TreeNodeProto.Builder.class);
+  }
+
+  public static final int VERSION_FIELD_NUMBER = 1;
+  private int version_;
+  /**
+   * <code>int32 version = 1;</code>
+   * @return The version.
+   */
+  @java.lang.Override
+  public int getVersion() {
+    return version_;
+  }
+
+  public static final int CLASS_NAME_FIELD_NUMBER = 2;
+  private volatile java.lang.Object className_;
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The className.
+   */
+  @java.lang.Override
+  public java.lang.String getClassName() {
+    java.lang.Object ref = className_;
+    if (ref instanceof java.lang.String) {
+      return (java.lang.String) ref;
+    } else {
+      com.google.protobuf.ByteString bs = 
+          (com.google.protobuf.ByteString) ref;
+      java.lang.String s = bs.toStringUtf8();
+      className_ = s;
+      return s;
+    }
+  }
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The bytes for className.
+   */
+  @java.lang.Override
+  public com.google.protobuf.ByteString
+      getClassNameBytes() {
+    java.lang.Object ref = className_;
+    if (ref instanceof java.lang.String) {
+      com.google.protobuf.ByteString b = 
+          com.google.protobuf.ByteString.copyFromUtf8(
+              (java.lang.String) ref);
+      className_ = b;
+      return b;
+    } else {
+      return (com.google.protobuf.ByteString) ref;
+    }
+  }
+
+  public static final int SERIALIZED_DATA_FIELD_NUMBER = 3;
+  private com.google.protobuf.Any serializedData_;
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return Whether the serializedData field is set.
+   */
+  @java.lang.Override
+  public boolean hasSerializedData() {
+    return serializedData_ != null;
+  }
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return The serializedData.
+   */
+  @java.lang.Override
+  public com.google.protobuf.Any getSerializedData() {
+    return serializedData_ == null ? com.google.protobuf.Any.getDefaultInstance() : serializedData_;
+  }
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   */
+  @java.lang.Override
+  public com.google.protobuf.AnyOrBuilder getSerializedDataOrBuilder() {
+    return getSerializedData();
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (version_ != 0) {
+      output.writeInt32(1, version_);
+    }
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(className_)) {
+      com.google.protobuf.GeneratedMessageV3.writeString(output, 2, className_);
+    }
+    if (serializedData_ != null) {
+      output.writeMessage(3, getSerializedData());
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (version_ != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeInt32Size(1, version_);
+    }
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(className_)) {
+      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, className_);
+    }
+    if (serializedData_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(3, getSerializedData());
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.common.tree.protos.TreeNodeProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.common.tree.protos.TreeNodeProto other = (org.tribuo.common.tree.protos.TreeNodeProto) obj;
+
+    if (getVersion()
+        != other.getVersion()) return false;
+    if (!getClassName()
+        .equals(other.getClassName())) return false;
+    if (hasSerializedData() != other.hasSerializedData()) return false;
+    if (hasSerializedData()) {
+      if (!getSerializedData()
+          .equals(other.getSerializedData())) return false;
+    }
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + VERSION_FIELD_NUMBER;
+    hash = (53 * hash) + getVersion();
+    hash = (37 * hash) + CLASS_NAME_FIELD_NUMBER;
+    hash = (53 * hash) + getClassName().hashCode();
+    if (hasSerializedData()) {
+      hash = (37 * hash) + SERIALIZED_DATA_FIELD_NUMBER;
+      hash = (53 * hash) + getSerializedData().hashCode();
+    }
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.common.tree.protos.TreeNodeProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.common.tree.protos.TreeNodeProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   **
+   *Tree Node proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.common.tree.TreeNodeProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.common.tree.TreeNodeProto)
+      org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeNodeProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeNodeProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.common.tree.protos.TreeNodeProto.class, org.tribuo.common.tree.protos.TreeNodeProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.common.tree.protos.TreeNodeProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      version_ = 0;
+
+      className_ = "";
+
+      if (serializedDataBuilder_ == null) {
+        serializedData_ = null;
+      } else {
+        serializedData_ = null;
+        serializedDataBuilder_ = null;
+      }
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.common.tree.protos.TribuoTree.internal_static_tribuo_common_tree_TreeNodeProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.TreeNodeProto getDefaultInstanceForType() {
+      return org.tribuo.common.tree.protos.TreeNodeProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.TreeNodeProto build() {
+      org.tribuo.common.tree.protos.TreeNodeProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.common.tree.protos.TreeNodeProto buildPartial() {
+      org.tribuo.common.tree.protos.TreeNodeProto result = new org.tribuo.common.tree.protos.TreeNodeProto(this);
+      result.version_ = version_;
+      result.className_ = className_;
+      if (serializedDataBuilder_ == null) {
+        result.serializedData_ = serializedData_;
+      } else {
+        result.serializedData_ = serializedDataBuilder_.build();
+      }
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.common.tree.protos.TreeNodeProto) {
+        return mergeFrom((org.tribuo.common.tree.protos.TreeNodeProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.common.tree.protos.TreeNodeProto other) {
+      if (other == org.tribuo.common.tree.protos.TreeNodeProto.getDefaultInstance()) return this;
+      if (other.getVersion() != 0) {
+        setVersion(other.getVersion());
+      }
+      if (!other.getClassName().isEmpty()) {
+        className_ = other.className_;
+        onChanged();
+      }
+      if (other.hasSerializedData()) {
+        mergeSerializedData(other.getSerializedData());
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.common.tree.protos.TreeNodeProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.common.tree.protos.TreeNodeProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+
+    private int version_ ;
+    /**
+     * <code>int32 version = 1;</code>
+     * @return The version.
+     */
+    @java.lang.Override
+    public int getVersion() {
+      return version_;
+    }
+    /**
+     * <code>int32 version = 1;</code>
+     * @param value The version to set.
+     * @return This builder for chaining.
+     */
+    public Builder setVersion(int value) {
+      
+      version_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>int32 version = 1;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearVersion() {
+      
+      version_ = 0;
+      onChanged();
+      return this;
+    }
+
+    private java.lang.Object className_ = "";
+    /**
+     * <code>string class_name = 2;</code>
+     * @return The className.
+     */
+    public java.lang.String getClassName() {
+      java.lang.Object ref = className_;
+      if (!(ref instanceof java.lang.String)) {
+        com.google.protobuf.ByteString bs =
+            (com.google.protobuf.ByteString) ref;
+        java.lang.String s = bs.toStringUtf8();
+        className_ = s;
+        return s;
+      } else {
+        return (java.lang.String) ref;
+      }
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @return The bytes for className.
+     */
+    public com.google.protobuf.ByteString
+        getClassNameBytes() {
+      java.lang.Object ref = className_;
+      if (ref instanceof String) {
+        com.google.protobuf.ByteString b = 
+            com.google.protobuf.ByteString.copyFromUtf8(
+                (java.lang.String) ref);
+        className_ = b;
+        return b;
+      } else {
+        return (com.google.protobuf.ByteString) ref;
+      }
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @param value The className to set.
+     * @return This builder for chaining.
+     */
+    public Builder setClassName(
+        java.lang.String value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  
+      className_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearClassName() {
+      
+      className_ = getDefaultInstance().getClassName();
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>string class_name = 2;</code>
+     * @param value The bytes for className to set.
+     * @return This builder for chaining.
+     */
+    public Builder setClassNameBytes(
+        com.google.protobuf.ByteString value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  checkByteStringIsUtf8(value);
+      
+      className_ = value;
+      onChanged();
+      return this;
+    }
+
+    private com.google.protobuf.Any serializedData_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder> serializedDataBuilder_;
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     * @return Whether the serializedData field is set.
+     */
+    public boolean hasSerializedData() {
+      return serializedDataBuilder_ != null || serializedData_ != null;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     * @return The serializedData.
+     */
+    public com.google.protobuf.Any getSerializedData() {
+      if (serializedDataBuilder_ == null) {
+        return serializedData_ == null ? com.google.protobuf.Any.getDefaultInstance() : serializedData_;
+      } else {
+        return serializedDataBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder setSerializedData(com.google.protobuf.Any value) {
+      if (serializedDataBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        serializedData_ = value;
+        onChanged();
+      } else {
+        serializedDataBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder setSerializedData(
+        com.google.protobuf.Any.Builder builderForValue) {
+      if (serializedDataBuilder_ == null) {
+        serializedData_ = builderForValue.build();
+        onChanged();
+      } else {
+        serializedDataBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder mergeSerializedData(com.google.protobuf.Any value) {
+      if (serializedDataBuilder_ == null) {
+        if (serializedData_ != null) {
+          serializedData_ =
+            com.google.protobuf.Any.newBuilder(serializedData_).mergeFrom(value).buildPartial();
+        } else {
+          serializedData_ = value;
+        }
+        onChanged();
+      } else {
+        serializedDataBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public Builder clearSerializedData() {
+      if (serializedDataBuilder_ == null) {
+        serializedData_ = null;
+        onChanged();
+      } else {
+        serializedData_ = null;
+        serializedDataBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public com.google.protobuf.Any.Builder getSerializedDataBuilder() {
+      
+      onChanged();
+      return getSerializedDataFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    public com.google.protobuf.AnyOrBuilder getSerializedDataOrBuilder() {
+      if (serializedDataBuilder_ != null) {
+        return serializedDataBuilder_.getMessageOrBuilder();
+      } else {
+        return serializedData_ == null ?
+            com.google.protobuf.Any.getDefaultInstance() : serializedData_;
+      }
+    }
+    /**
+     * <code>.google.protobuf.Any serialized_data = 3;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder> 
+        getSerializedDataFieldBuilder() {
+      if (serializedDataBuilder_ == null) {
+        serializedDataBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            com.google.protobuf.Any, com.google.protobuf.Any.Builder, com.google.protobuf.AnyOrBuilder>(
+                getSerializedData(),
+                getParentForChildren(),
+                isClean());
+        serializedData_ = null;
+      }
+      return serializedDataBuilder_;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.common.tree.TreeNodeProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.common.tree.TreeNodeProto)
+  private static final org.tribuo.common.tree.protos.TreeNodeProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.common.tree.protos.TreeNodeProto();
+  }
+
+  public static org.tribuo.common.tree.protos.TreeNodeProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<TreeNodeProto>
+      PARSER = new com.google.protobuf.AbstractParser<TreeNodeProto>() {
+    @java.lang.Override
+    public TreeNodeProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new TreeNodeProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<TreeNodeProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<TreeNodeProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.TreeNodeProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProtoOrBuilder.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProtoOrBuilder.java
new file mode 100644
index 000000000..387853942
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TreeNodeProtoOrBuilder.java
@@ -0,0 +1,42 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+public interface TreeNodeProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.common.tree.TreeNodeProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>int32 version = 1;</code>
+   * @return The version.
+   */
+  int getVersion();
+
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The className.
+   */
+  java.lang.String getClassName();
+  /**
+   * <code>string class_name = 2;</code>
+   * @return The bytes for className.
+   */
+  com.google.protobuf.ByteString
+      getClassNameBytes();
+
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return Whether the serializedData field is set.
+   */
+  boolean hasSerializedData();
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   * @return The serializedData.
+   */
+  com.google.protobuf.Any getSerializedData();
+  /**
+   * <code>.google.protobuf.Any serialized_data = 3;</code>
+   */
+  com.google.protobuf.AnyOrBuilder getSerializedDataOrBuilder();
+}
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TribuoTree.java b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TribuoTree.java
new file mode 100644
index 000000000..655b72e9c
--- /dev/null
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/protos/TribuoTree.java
@@ -0,0 +1,114 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-tree.proto
+
+package org.tribuo.common.tree.protos;
+
+public final class TribuoTree {
+  private TribuoTree() {}
+  public static void registerAllExtensions(
+      com.google.protobuf.ExtensionRegistryLite registry) {
+  }
+
+  public static void registerAllExtensions(
+      com.google.protobuf.ExtensionRegistry registry) {
+    registerAllExtensions(
+        (com.google.protobuf.ExtensionRegistryLite) registry);
+  }
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_tree_TreeNodeProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_tree_TreeNodeProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_tree_SplitNodeProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_tree_SplitNodeProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_tree_LeafNodeProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_tree_LeafNodeProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_tree_LeafNodeProto_ScoreEntry_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_tree_LeafNodeProto_ScoreEntry_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_common_tree_TreeModelProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_common_tree_TreeModelProto_fieldAccessorTable;
+
+  public static com.google.protobuf.Descriptors.FileDescriptor
+      getDescriptor() {
+    return descriptor;
+  }
+  private static  com.google.protobuf.Descriptors.FileDescriptor
+      descriptor;
+  static {
+    java.lang.String[] descriptorData = {
+      "\n\021tribuo-tree.proto\022\022tribuo.common.tree\032" +
+      "\031google/protobuf/any.proto\032\021tribuo-core." +
+      "proto\"c\n\rTreeNodeProto\022\017\n\007version\030\001 \001(\005\022" +
+      "\022\n\nclass_name\030\002 \001(\t\022-\n\017serialized_data\030\003" +
+      " \001(\0132\024.google.protobuf.Any\"\261\001\n\016SplitNode" +
+      "Proto\022\022\n\nparent_idx\030\001 \001(\005\022\017\n\007cur_idx\030\002 \001" +
+      "(\005\022\030\n\020greater_than_idx\030\003 \001(\005\022\036\n\026less_tha" +
+      "n_or_equal_idx\030\004 \001(\005\022\031\n\021split_feature_id" +
+      "x\030\005 \001(\005\022\023\n\013split_value\030\006 \001(\001\022\020\n\010impurity" +
+      "\030\007 \001(\001\"\226\002\n\rLeafNodeProto\022\022\n\nparent_idx\030\001" +
+      " \001(\005\022\017\n\007cur_idx\030\002 \001(\005\022\020\n\010impurity\030\003 \001(\001\022" +
+      "(\n\006output\030\004 \001(\0132\030.tribuo.core.OutputProt" +
+      "o\022;\n\005score\030\005 \003(\0132,.tribuo.common.tree.Le" +
+      "afNodeProto.ScoreEntry\022\037\n\027generates_prob" +
+      "abilities\030\006 \001(\010\032F\n\nScoreEntry\022\013\n\003key\030\001 \001" +
+      "(\t\022\'\n\005value\030\002 \001(\0132\030.tribuo.core.OutputPr" +
+      "oto:\0028\001\"q\n\016TreeModelProto\022-\n\010metadata\030\001 " +
+      "\001(\0132\033.tribuo.core.ModelDataProto\0220\n\005node" +
+      "s\030\002 \003(\0132!.tribuo.common.tree.TreeNodePro" +
+      "toB!\n\035org.tribuo.common.tree.protosP\001b\006p" +
+      "roto3"
+    };
+    descriptor = com.google.protobuf.Descriptors.FileDescriptor
+      .internalBuildGeneratedFileFrom(descriptorData,
+        new com.google.protobuf.Descriptors.FileDescriptor[] {
+          com.google.protobuf.AnyProto.getDescriptor(),
+          org.tribuo.protos.core.TribuoCore.getDescriptor(),
+        });
+    internal_static_tribuo_common_tree_TreeNodeProto_descriptor =
+      getDescriptor().getMessageTypes().get(0);
+    internal_static_tribuo_common_tree_TreeNodeProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_tree_TreeNodeProto_descriptor,
+        new java.lang.String[] { "Version", "ClassName", "SerializedData", });
+    internal_static_tribuo_common_tree_SplitNodeProto_descriptor =
+      getDescriptor().getMessageTypes().get(1);
+    internal_static_tribuo_common_tree_SplitNodeProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_tree_SplitNodeProto_descriptor,
+        new java.lang.String[] { "ParentIdx", "CurIdx", "GreaterThanIdx", "LessThanOrEqualIdx", "SplitFeatureIdx", "SplitValue", "Impurity", });
+    internal_static_tribuo_common_tree_LeafNodeProto_descriptor =
+      getDescriptor().getMessageTypes().get(2);
+    internal_static_tribuo_common_tree_LeafNodeProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_tree_LeafNodeProto_descriptor,
+        new java.lang.String[] { "ParentIdx", "CurIdx", "Impurity", "Output", "Score", "GeneratesProbabilities", });
+    internal_static_tribuo_common_tree_LeafNodeProto_ScoreEntry_descriptor =
+      internal_static_tribuo_common_tree_LeafNodeProto_descriptor.getNestedTypes().get(0);
+    internal_static_tribuo_common_tree_LeafNodeProto_ScoreEntry_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_tree_LeafNodeProto_ScoreEntry_descriptor,
+        new java.lang.String[] { "Key", "Value", });
+    internal_static_tribuo_common_tree_TreeModelProto_descriptor =
+      getDescriptor().getMessageTypes().get(3);
+    internal_static_tribuo_common_tree_TreeModelProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_common_tree_TreeModelProto_descriptor,
+        new java.lang.String[] { "Metadata", "Nodes", });
+    com.google.protobuf.AnyProto.getDescriptor();
+    org.tribuo.protos.core.TribuoCore.getDescriptor();
+  }
+
+  // @@protoc_insertion_point(outer_class_scope)
+}
diff --git a/Common/Trees/src/main/resources/protos/tribuo-tree.proto b/Common/Trees/src/main/resources/protos/tribuo-tree.proto
index d89c93a5e..2d8c92cee 100644
--- a/Common/Trees/src/main/resources/protos/tribuo-tree.proto
+++ b/Common/Trees/src/main/resources/protos/tribuo-tree.proto
@@ -19,7 +19,7 @@ syntax = "proto3";
 /*
  * Protos for serializing Tribuo trees.
  */
-package tribuo.tree;
+package tribuo.common.tree;
 
 option java_multiple_files = true;
 option java_package = "org.tribuo.common.tree.protos";
@@ -44,11 +44,12 @@ SplitNode proto
  */
 message SplitNodeProto {
   int32 parent_idx = 1;
-  int32 greater_than_idx = 2;
-  int32 less_than_or_equal_idx = 3;
-  int32 split_feature_idx = 4;
-  double split_value = 5;
-  double impurity = 6;
+  int32 cur_idx = 2;
+  int32 greater_than_idx = 3;
+  int32 less_than_or_equal_idx = 4;
+  int32 split_feature_idx = 5;
+  double split_value = 6;
+  double impurity = 7;
 }
 
 /*
@@ -56,10 +57,11 @@ LeafNode proto
  */
 message LeafNodeProto {
   int32 parent_idx = 1;
-  double impurity = 2;
-  tribuo.core.OutputProto output = 3;
-  map<string,tribuo.core.OutputProto> score = 4;
-  bool generates_probabilities = 5;
+  int32 cur_idx = 2;
+  double impurity = 3;
+  tribuo.core.OutputProto output = 4;
+  map<string,tribuo.core.OutputProto> score = 5;
+  bool generates_probabilities = 6;
 }
 
 /*
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java
index 1c98dd880..03f12a598 100644
--- a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@
 
 package org.tribuo.regression.rtree;
 
+import com.google.protobuf.Any;
+import com.google.protobuf.InvalidProtocolBufferException;
 import com.oracle.labs.mlrg.olcut.util.Pair;
 import org.tribuo.Example;
 import org.tribuo.Excuse;
@@ -27,10 +29,16 @@
 import org.tribuo.common.tree.Node;
 import org.tribuo.common.tree.SplitNode;
 import org.tribuo.common.tree.TreeModel;
+import org.tribuo.common.tree.protos.TreeModelProto;
+import org.tribuo.common.tree.protos.TreeNodeProto;
+import org.tribuo.impl.ModelDataCarrier;
 import org.tribuo.math.la.SparseVector;
+import org.tribuo.protos.core.ModelProto;
 import org.tribuo.provenance.ModelProvenance;
 import org.tribuo.regression.Regressor;
 import org.tribuo.regression.Regressor.DimensionTuple;
+import org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto;
+import org.tribuo.regression.rtree.protos.TreeNodeListProto;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -53,15 +61,60 @@
 public final class IndependentRegressionTreeModel extends TreeModel<Regressor> {
     private static final long serialVersionUID = 1L;
 
+    /**
+     * Protobuf serialization version.
+     */
+    public static final int CURRENT_VERSION = 0;
+
     private final Map<String,Node<Regressor>> roots;
 
     IndependentRegressionTreeModel(String name, ModelProvenance description,
-                                          ImmutableFeatureMap featureIDMap, ImmutableOutputInfo<Regressor> outputIDInfo, boolean generatesProbabilities,
-                                          Map<String,Node<Regressor>> roots) {
+                                   ImmutableFeatureMap featureIDMap, ImmutableOutputInfo<Regressor> outputIDInfo, boolean generatesProbabilities,
+                                   Map<String,Node<Regressor>> roots) {
         super(name, description, featureIDMap, outputIDInfo, generatesProbabilities, gatherActiveFeatures(featureIDMap,roots));
         this.roots = roots;
     }
 
+    /**
+     * Deserialization factory.
+     * @param version The serialized object version.
+     * @param className The class name.
+     * @param message The serialized data.
+     */
+    @SuppressWarnings({"unchecked","rawtypes"}) // guarded by getClass to ensure all the output types are the same.
+    public static IndependentRegressionTreeModel deserializeFromProto(int version, String className, Any message) throws InvalidProtocolBufferException {
+        if (version < 0 || version > CURRENT_VERSION) {
+            throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + CURRENT_VERSION);
+        }
+        IndependentRegressionTreeModelProto proto = message.unpack(IndependentRegressionTreeModelProto.class);
+
+        ModelDataCarrier<?> carrier = ModelDataCarrier.deserialize(proto.getMetadata());
+        if (!carrier.outputDomain().getOutput(0).getClass().equals(Regressor.class)) {
+            throw new IllegalStateException("Invalid protobuf, output domain is not a regression domain, found " + carrier.outputDomain().getClass());
+        }
+        @SuppressWarnings("unchecked") // guarded by getClass
+        ImmutableOutputInfo<Regressor> outputDomain = (ImmutableOutputInfo<Regressor>) carrier.outputDomain();
+
+        if (proto.getNodesCount() == 0) {
+            throw new IllegalStateException("Invalid protobuf, tree must contain nodes");
+        } else if (proto.getNodesCount() != outputDomain.size()) {
+            throw new IllegalStateException("Invalid protobuf, must have one tree per output dimension, found " + proto.getNodesCount());
+        }
+
+        Map<String,Node<Regressor>> map = new HashMap<>();
+
+        for (Map.Entry<String, TreeNodeListProto> e : proto.getNodesMap().entrySet()) {
+            List<TreeNodeProto> nodeProtos = e.getValue().getNodesList();
+            if (nodeProtos.size() == 0) {
+                throw new IllegalStateException("Invalid protobuf, tree must contain nodes");
+            }
+            List<Node<Regressor>> nodes = deserializeFromProtos(nodeProtos, Regressor.class);
+            map.put(e.getKey(), nodes.get(0));
+        }
+
+        return new IndependentRegressionTreeModel(carrier.name(),carrier.provenance(),carrier.featureDomain(),outputDomain,carrier.generatesProbabilities(),map);
+    }
+
     private static Map<String,List<String>> gatherActiveFeatures(ImmutableFeatureMap fMap, Map<String,Node<Regressor>> roots) {
         HashMap<String,List<String>> outputMap = new HashMap<>();
         for (Map.Entry<String,Node<Regressor>> e : roots.entrySet()) {
@@ -309,4 +362,23 @@ public Map<String,Node<Regressor>> getRoots() {
     public Node<Regressor> getRoot() {
         return null;
     }
+
+    @Override
+    public ModelProto serialize() {
+        ModelDataCarrier<Regressor> carrier = createDataCarrier();
+
+        IndependentRegressionTreeModelProto.Builder modelBuilder = IndependentRegressionTreeModelProto.newBuilder();
+        modelBuilder.setMetadata(carrier.serialize());
+        for (Map.Entry<String, Node<Regressor>> e : roots.entrySet()) {
+            TreeNodeListProto listProto = TreeNodeListProto.newBuilder().addAllNodes(serializeToNodes(e.getValue())).build();
+            modelBuilder.putNodes(e.getKey(), listProto);
+        }
+
+        ModelProto.Builder builder = ModelProto.newBuilder();
+        builder.setSerializedData(Any.pack(modelBuilder.build()));
+        builder.setClassName(TreeModel.class.getName());
+        builder.setVersion(CURRENT_VERSION);
+
+        return builder.build();
+    }
 }
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProto.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProto.java
new file mode 100644
index 000000000..d2ab9f81a
--- /dev/null
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProto.java
@@ -0,0 +1,904 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-tree.proto
+
+package org.tribuo.regression.rtree.protos;
+
+/**
+ * <pre>
+ *IndependentRegressionTreeModel proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.regression.tree.IndependentRegressionTreeModelProto}
+ */
+public final class IndependentRegressionTreeModelProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.regression.tree.IndependentRegressionTreeModelProto)
+    IndependentRegressionTreeModelProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use IndependentRegressionTreeModelProto.newBuilder() to construct.
+  private IndependentRegressionTreeModelProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private IndependentRegressionTreeModelProto() {
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new IndependentRegressionTreeModelProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private IndependentRegressionTreeModelProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    int mutable_bitField0_ = 0;
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 10: {
+            org.tribuo.protos.core.ModelDataProto.Builder subBuilder = null;
+            if (metadata_ != null) {
+              subBuilder = metadata_.toBuilder();
+            }
+            metadata_ = input.readMessage(org.tribuo.protos.core.ModelDataProto.parser(), extensionRegistry);
+            if (subBuilder != null) {
+              subBuilder.mergeFrom(metadata_);
+              metadata_ = subBuilder.buildPartial();
+            }
+
+            break;
+          }
+          case 18: {
+            if (!((mutable_bitField0_ & 0x00000001) != 0)) {
+              nodes_ = com.google.protobuf.MapField.newMapField(
+                  NodesDefaultEntryHolder.defaultEntry);
+              mutable_bitField0_ |= 0x00000001;
+            }
+            com.google.protobuf.MapEntry<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+            nodes__ = input.readMessage(
+                NodesDefaultEntryHolder.defaultEntry.getParserForType(), extensionRegistry);
+            nodes_.getMutableMap().put(
+                nodes__.getKey(), nodes__.getValue());
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor;
+  }
+
+  @SuppressWarnings({"rawtypes"})
+  @java.lang.Override
+  protected com.google.protobuf.MapField internalGetMapField(
+      int number) {
+    switch (number) {
+      case 2:
+        return internalGetNodes();
+      default:
+        throw new RuntimeException(
+            "Invalid map field number: " + number);
+    }
+  }
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.class, org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.Builder.class);
+  }
+
+  public static final int METADATA_FIELD_NUMBER = 1;
+  private org.tribuo.protos.core.ModelDataProto metadata_;
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  @java.lang.Override
+  public boolean hasMetadata() {
+    return metadata_ != null;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProto getMetadata() {
+    return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+  }
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+    return getMetadata();
+  }
+
+  public static final int NODES_FIELD_NUMBER = 2;
+  private static final class NodesDefaultEntryHolder {
+    static final com.google.protobuf.MapEntry<
+        java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> defaultEntry =
+            com.google.protobuf.MapEntry
+            .<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>newDefaultInstance(
+                org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_NodesEntry_descriptor, 
+                com.google.protobuf.WireFormat.FieldType.STRING,
+                "",
+                com.google.protobuf.WireFormat.FieldType.MESSAGE,
+                org.tribuo.regression.rtree.protos.TreeNodeListProto.getDefaultInstance());
+  }
+  private com.google.protobuf.MapField<
+      java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> nodes_;
+  private com.google.protobuf.MapField<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+  internalGetNodes() {
+    if (nodes_ == null) {
+      return com.google.protobuf.MapField.emptyMapField(
+          NodesDefaultEntryHolder.defaultEntry);
+    }
+    return nodes_;
+  }
+
+  public int getNodesCount() {
+    return internalGetNodes().getMap().size();
+  }
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+
+  @java.lang.Override
+  public boolean containsNodes(
+      java.lang.String key) {
+    if (key == null) { throw new NullPointerException("map key"); }
+    return internalGetNodes().getMap().containsKey(key);
+  }
+  /**
+   * Use {@link #getNodesMap()} instead.
+   */
+  @java.lang.Override
+  @java.lang.Deprecated
+  public java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> getNodes() {
+    return getNodesMap();
+  }
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+  @java.lang.Override
+
+  public java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> getNodesMap() {
+    return internalGetNodes().getMap();
+  }
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+  @java.lang.Override
+
+  public org.tribuo.regression.rtree.protos.TreeNodeListProto getNodesOrDefault(
+      java.lang.String key,
+      org.tribuo.regression.rtree.protos.TreeNodeListProto defaultValue) {
+    if (key == null) { throw new NullPointerException("map key"); }
+    java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> map =
+        internalGetNodes().getMap();
+    return map.containsKey(key) ? map.get(key) : defaultValue;
+  }
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+  @java.lang.Override
+
+  public org.tribuo.regression.rtree.protos.TreeNodeListProto getNodesOrThrow(
+      java.lang.String key) {
+    if (key == null) { throw new NullPointerException("map key"); }
+    java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> map =
+        internalGetNodes().getMap();
+    if (!map.containsKey(key)) {
+      throw new java.lang.IllegalArgumentException();
+    }
+    return map.get(key);
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (metadata_ != null) {
+      output.writeMessage(1, getMetadata());
+    }
+    com.google.protobuf.GeneratedMessageV3
+      .serializeStringMapTo(
+        output,
+        internalGetNodes(),
+        NodesDefaultEntryHolder.defaultEntry,
+        2);
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (metadata_ != null) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(1, getMetadata());
+    }
+    for (java.util.Map.Entry<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> entry
+         : internalGetNodes().getMap().entrySet()) {
+      com.google.protobuf.MapEntry<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+      nodes__ = NodesDefaultEntryHolder.defaultEntry.newBuilderForType()
+          .setKey(entry.getKey())
+          .setValue(entry.getValue())
+          .build();
+      size += com.google.protobuf.CodedOutputStream
+          .computeMessageSize(2, nodes__);
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto other = (org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto) obj;
+
+    if (hasMetadata() != other.hasMetadata()) return false;
+    if (hasMetadata()) {
+      if (!getMetadata()
+          .equals(other.getMetadata())) return false;
+    }
+    if (!internalGetNodes().equals(
+        other.internalGetNodes())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    if (hasMetadata()) {
+      hash = (37 * hash) + METADATA_FIELD_NUMBER;
+      hash = (53 * hash) + getMetadata().hashCode();
+    }
+    if (!internalGetNodes().getMap().isEmpty()) {
+      hash = (37 * hash) + NODES_FIELD_NUMBER;
+      hash = (53 * hash) + internalGetNodes().hashCode();
+    }
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *IndependentRegressionTreeModel proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.regression.tree.IndependentRegressionTreeModelProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.regression.tree.IndependentRegressionTreeModelProto)
+      org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor;
+    }
+
+    @SuppressWarnings({"rawtypes"})
+    protected com.google.protobuf.MapField internalGetMapField(
+        int number) {
+      switch (number) {
+        case 2:
+          return internalGetNodes();
+        default:
+          throw new RuntimeException(
+              "Invalid map field number: " + number);
+      }
+    }
+    @SuppressWarnings({"rawtypes"})
+    protected com.google.protobuf.MapField internalGetMutableMapField(
+        int number) {
+      switch (number) {
+        case 2:
+          return internalGetMutableNodes();
+        default:
+          throw new RuntimeException(
+              "Invalid map field number: " + number);
+      }
+    }
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.class, org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+      internalGetMutableNodes().clear();
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto getDefaultInstanceForType() {
+      return org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto build() {
+      org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto buildPartial() {
+      org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto result = new org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto(this);
+      int from_bitField0_ = bitField0_;
+      if (metadataBuilder_ == null) {
+        result.metadata_ = metadata_;
+      } else {
+        result.metadata_ = metadataBuilder_.build();
+      }
+      result.nodes_ = internalGetNodes();
+      result.nodes_.makeImmutable();
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto) {
+        return mergeFrom((org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto other) {
+      if (other == org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto.getDefaultInstance()) return this;
+      if (other.hasMetadata()) {
+        mergeMetadata(other.getMetadata());
+      }
+      internalGetMutableNodes().mergeFrom(
+          other.internalGetNodes());
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+    private int bitField0_;
+
+    private org.tribuo.protos.core.ModelDataProto metadata_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> metadataBuilder_;
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return Whether the metadata field is set.
+     */
+    public boolean hasMetadata() {
+      return metadataBuilder_ != null || metadata_ != null;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     * @return The metadata.
+     */
+    public org.tribuo.protos.core.ModelDataProto getMetadata() {
+      if (metadataBuilder_ == null) {
+        return metadata_ == null ? org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      } else {
+        return metadataBuilder_.getMessage();
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        metadata_ = value;
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder setMetadata(
+        org.tribuo.protos.core.ModelDataProto.Builder builderForValue) {
+      if (metadataBuilder_ == null) {
+        metadata_ = builderForValue.build();
+        onChanged();
+      } else {
+        metadataBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder mergeMetadata(org.tribuo.protos.core.ModelDataProto value) {
+      if (metadataBuilder_ == null) {
+        if (metadata_ != null) {
+          metadata_ =
+            org.tribuo.protos.core.ModelDataProto.newBuilder(metadata_).mergeFrom(value).buildPartial();
+        } else {
+          metadata_ = value;
+        }
+        onChanged();
+      } else {
+        metadataBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public Builder clearMetadata() {
+      if (metadataBuilder_ == null) {
+        metadata_ = null;
+        onChanged();
+      } else {
+        metadata_ = null;
+        metadataBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProto.Builder getMetadataBuilder() {
+      
+      onChanged();
+      return getMetadataFieldBuilder().getBuilder();
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    public org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder() {
+      if (metadataBuilder_ != null) {
+        return metadataBuilder_.getMessageOrBuilder();
+      } else {
+        return metadata_ == null ?
+            org.tribuo.protos.core.ModelDataProto.getDefaultInstance() : metadata_;
+      }
+    }
+    /**
+     * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+        org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder> 
+        getMetadataFieldBuilder() {
+      if (metadataBuilder_ == null) {
+        metadataBuilder_ = new com.google.protobuf.SingleFieldBuilderV3<
+            org.tribuo.protos.core.ModelDataProto, org.tribuo.protos.core.ModelDataProto.Builder, org.tribuo.protos.core.ModelDataProtoOrBuilder>(
+                getMetadata(),
+                getParentForChildren(),
+                isClean());
+        metadata_ = null;
+      }
+      return metadataBuilder_;
+    }
+
+    private com.google.protobuf.MapField<
+        java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> nodes_;
+    private com.google.protobuf.MapField<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+    internalGetNodes() {
+      if (nodes_ == null) {
+        return com.google.protobuf.MapField.emptyMapField(
+            NodesDefaultEntryHolder.defaultEntry);
+      }
+      return nodes_;
+    }
+    private com.google.protobuf.MapField<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+    internalGetMutableNodes() {
+      onChanged();;
+      if (nodes_ == null) {
+        nodes_ = com.google.protobuf.MapField.newMapField(
+            NodesDefaultEntryHolder.defaultEntry);
+      }
+      if (!nodes_.isMutable()) {
+        nodes_ = nodes_.copy();
+      }
+      return nodes_;
+    }
+
+    public int getNodesCount() {
+      return internalGetNodes().getMap().size();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+
+    @java.lang.Override
+    public boolean containsNodes(
+        java.lang.String key) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      return internalGetNodes().getMap().containsKey(key);
+    }
+    /**
+     * Use {@link #getNodesMap()} instead.
+     */
+    @java.lang.Override
+    @java.lang.Deprecated
+    public java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> getNodes() {
+      return getNodesMap();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+    @java.lang.Override
+
+    public java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> getNodesMap() {
+      return internalGetNodes().getMap();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+    @java.lang.Override
+
+    public org.tribuo.regression.rtree.protos.TreeNodeListProto getNodesOrDefault(
+        java.lang.String key,
+        org.tribuo.regression.rtree.protos.TreeNodeListProto defaultValue) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> map =
+          internalGetNodes().getMap();
+      return map.containsKey(key) ? map.get(key) : defaultValue;
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+    @java.lang.Override
+
+    public org.tribuo.regression.rtree.protos.TreeNodeListProto getNodesOrThrow(
+        java.lang.String key) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> map =
+          internalGetNodes().getMap();
+      if (!map.containsKey(key)) {
+        throw new java.lang.IllegalArgumentException();
+      }
+      return map.get(key);
+    }
+
+    public Builder clearNodes() {
+      internalGetMutableNodes().getMutableMap()
+          .clear();
+      return this;
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+
+    public Builder removeNodes(
+        java.lang.String key) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      internalGetMutableNodes().getMutableMap()
+          .remove(key);
+      return this;
+    }
+    /**
+     * Use alternate mutation accessors instead.
+     */
+    @java.lang.Deprecated
+    public java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+    getMutableNodes() {
+      return internalGetMutableNodes().getMutableMap();
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+    public Builder putNodes(
+        java.lang.String key,
+        org.tribuo.regression.rtree.protos.TreeNodeListProto value) {
+      if (key == null) { throw new NullPointerException("map key"); }
+      if (value == null) {
+  throw new NullPointerException("map value");
+}
+
+      internalGetMutableNodes().getMutableMap()
+          .put(key, value);
+      return this;
+    }
+    /**
+     * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+     */
+
+    public Builder putAllNodes(
+        java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto> values) {
+      internalGetMutableNodes().getMutableMap()
+          .putAll(values);
+      return this;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.regression.tree.IndependentRegressionTreeModelProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.regression.tree.IndependentRegressionTreeModelProto)
+  private static final org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto();
+  }
+
+  public static org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<IndependentRegressionTreeModelProto>
+      PARSER = new com.google.protobuf.AbstractParser<IndependentRegressionTreeModelProto>() {
+    @java.lang.Override
+    public IndependentRegressionTreeModelProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new IndependentRegressionTreeModelProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<IndependentRegressionTreeModelProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<IndependentRegressionTreeModelProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.regression.rtree.protos.IndependentRegressionTreeModelProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProtoOrBuilder.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProtoOrBuilder.java
new file mode 100644
index 000000000..8b9980120
--- /dev/null
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/IndependentRegressionTreeModelProtoOrBuilder.java
@@ -0,0 +1,58 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-tree.proto
+
+package org.tribuo.regression.rtree.protos;
+
+public interface IndependentRegressionTreeModelProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.regression.tree.IndependentRegressionTreeModelProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return Whether the metadata field is set.
+   */
+  boolean hasMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   * @return The metadata.
+   */
+  org.tribuo.protos.core.ModelDataProto getMetadata();
+  /**
+   * <code>.tribuo.core.ModelDataProto metadata = 1;</code>
+   */
+  org.tribuo.protos.core.ModelDataProtoOrBuilder getMetadataOrBuilder();
+
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+  int getNodesCount();
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+  boolean containsNodes(
+      java.lang.String key);
+  /**
+   * Use {@link #getNodesMap()} instead.
+   */
+  @java.lang.Deprecated
+  java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+  getNodes();
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+  java.util.Map<java.lang.String, org.tribuo.regression.rtree.protos.TreeNodeListProto>
+  getNodesMap();
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+
+  org.tribuo.regression.rtree.protos.TreeNodeListProto getNodesOrDefault(
+      java.lang.String key,
+      org.tribuo.regression.rtree.protos.TreeNodeListProto defaultValue);
+  /**
+   * <code>map&lt;string, .tribuo.regression.tree.TreeNodeListProto&gt; nodes = 2;</code>
+   */
+
+  org.tribuo.regression.rtree.protos.TreeNodeListProto getNodesOrThrow(
+      java.lang.String key);
+}
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProto.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProto.java
new file mode 100644
index 000000000..c9c1c3901
--- /dev/null
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProto.java
@@ -0,0 +1,778 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-tree.proto
+
+package org.tribuo.regression.rtree.protos;
+
+/**
+ * <pre>
+ *Carrier for a list of tree nodes.
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.regression.tree.TreeNodeListProto}
+ */
+public final class TreeNodeListProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.regression.tree.TreeNodeListProto)
+    TreeNodeListProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use TreeNodeListProto.newBuilder() to construct.
+  private TreeNodeListProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private TreeNodeListProto() {
+    nodes_ = java.util.Collections.emptyList();
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new TreeNodeListProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private TreeNodeListProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    int mutable_bitField0_ = 0;
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 26: {
+            if (!((mutable_bitField0_ & 0x00000001) != 0)) {
+              nodes_ = new java.util.ArrayList<org.tribuo.common.tree.protos.TreeNodeProto>();
+              mutable_bitField0_ |= 0x00000001;
+            }
+            nodes_.add(
+                input.readMessage(org.tribuo.common.tree.protos.TreeNodeProto.parser(), extensionRegistry));
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      if (((mutable_bitField0_ & 0x00000001) != 0)) {
+        nodes_ = java.util.Collections.unmodifiableList(nodes_);
+      }
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_TreeNodeListProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_TreeNodeListProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.regression.rtree.protos.TreeNodeListProto.class, org.tribuo.regression.rtree.protos.TreeNodeListProto.Builder.class);
+  }
+
+  public static final int NODES_FIELD_NUMBER = 3;
+  private java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> nodes_;
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  @java.lang.Override
+  public java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> getNodesList() {
+    return nodes_;
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  @java.lang.Override
+  public java.util.List<? extends org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+      getNodesOrBuilderList() {
+    return nodes_;
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  @java.lang.Override
+  public int getNodesCount() {
+    return nodes_.size();
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.TreeNodeProto getNodes(int index) {
+    return nodes_.get(index);
+  }
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  @java.lang.Override
+  public org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder getNodesOrBuilder(
+      int index) {
+    return nodes_.get(index);
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    for (int i = 0; i < nodes_.size(); i++) {
+      output.writeMessage(3, nodes_.get(i));
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    for (int i = 0; i < nodes_.size(); i++) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeMessageSize(3, nodes_.get(i));
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.regression.rtree.protos.TreeNodeListProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.regression.rtree.protos.TreeNodeListProto other = (org.tribuo.regression.rtree.protos.TreeNodeListProto) obj;
+
+    if (!getNodesList()
+        .equals(other.getNodesList())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    if (getNodesCount() > 0) {
+      hash = (37 * hash) + NODES_FIELD_NUMBER;
+      hash = (53 * hash) + getNodesList().hashCode();
+    }
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.regression.rtree.protos.TreeNodeListProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *Carrier for a list of tree nodes.
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.regression.tree.TreeNodeListProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.regression.tree.TreeNodeListProto)
+      org.tribuo.regression.rtree.protos.TreeNodeListProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_TreeNodeListProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_TreeNodeListProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.regression.rtree.protos.TreeNodeListProto.class, org.tribuo.regression.rtree.protos.TreeNodeListProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.regression.rtree.protos.TreeNodeListProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+        getNodesFieldBuilder();
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      if (nodesBuilder_ == null) {
+        nodes_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00000001);
+      } else {
+        nodesBuilder_.clear();
+      }
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.regression.rtree.protos.TribuoRegressionTree.internal_static_tribuo_regression_tree_TreeNodeListProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.rtree.protos.TreeNodeListProto getDefaultInstanceForType() {
+      return org.tribuo.regression.rtree.protos.TreeNodeListProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.rtree.protos.TreeNodeListProto build() {
+      org.tribuo.regression.rtree.protos.TreeNodeListProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.rtree.protos.TreeNodeListProto buildPartial() {
+      org.tribuo.regression.rtree.protos.TreeNodeListProto result = new org.tribuo.regression.rtree.protos.TreeNodeListProto(this);
+      int from_bitField0_ = bitField0_;
+      if (nodesBuilder_ == null) {
+        if (((bitField0_ & 0x00000001) != 0)) {
+          nodes_ = java.util.Collections.unmodifiableList(nodes_);
+          bitField0_ = (bitField0_ & ~0x00000001);
+        }
+        result.nodes_ = nodes_;
+      } else {
+        result.nodes_ = nodesBuilder_.build();
+      }
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.regression.rtree.protos.TreeNodeListProto) {
+        return mergeFrom((org.tribuo.regression.rtree.protos.TreeNodeListProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.regression.rtree.protos.TreeNodeListProto other) {
+      if (other == org.tribuo.regression.rtree.protos.TreeNodeListProto.getDefaultInstance()) return this;
+      if (nodesBuilder_ == null) {
+        if (!other.nodes_.isEmpty()) {
+          if (nodes_.isEmpty()) {
+            nodes_ = other.nodes_;
+            bitField0_ = (bitField0_ & ~0x00000001);
+          } else {
+            ensureNodesIsMutable();
+            nodes_.addAll(other.nodes_);
+          }
+          onChanged();
+        }
+      } else {
+        if (!other.nodes_.isEmpty()) {
+          if (nodesBuilder_.isEmpty()) {
+            nodesBuilder_.dispose();
+            nodesBuilder_ = null;
+            nodes_ = other.nodes_;
+            bitField0_ = (bitField0_ & ~0x00000001);
+            nodesBuilder_ = 
+              com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders ?
+                 getNodesFieldBuilder() : null;
+          } else {
+            nodesBuilder_.addAllMessages(other.nodes_);
+          }
+        }
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.regression.rtree.protos.TreeNodeListProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.regression.rtree.protos.TreeNodeListProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+    private int bitField0_;
+
+    private java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> nodes_ =
+      java.util.Collections.emptyList();
+    private void ensureNodesIsMutable() {
+      if (!((bitField0_ & 0x00000001) != 0)) {
+        nodes_ = new java.util.ArrayList<org.tribuo.common.tree.protos.TreeNodeProto>(nodes_);
+        bitField0_ |= 0x00000001;
+       }
+    }
+
+    private com.google.protobuf.RepeatedFieldBuilderV3<
+        org.tribuo.common.tree.protos.TreeNodeProto, org.tribuo.common.tree.protos.TreeNodeProto.Builder, org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> nodesBuilder_;
+
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> getNodesList() {
+      if (nodesBuilder_ == null) {
+        return java.util.Collections.unmodifiableList(nodes_);
+      } else {
+        return nodesBuilder_.getMessageList();
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public int getNodesCount() {
+      if (nodesBuilder_ == null) {
+        return nodes_.size();
+      } else {
+        return nodesBuilder_.getCount();
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto getNodes(int index) {
+      if (nodesBuilder_ == null) {
+        return nodes_.get(index);
+      } else {
+        return nodesBuilder_.getMessage(index);
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder setNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto value) {
+      if (nodesBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureNodesIsMutable();
+        nodes_.set(index, value);
+        onChanged();
+      } else {
+        nodesBuilder_.setMessage(index, value);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder setNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto.Builder builderForValue) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.set(index, builderForValue.build());
+        onChanged();
+      } else {
+        nodesBuilder_.setMessage(index, builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder addNodes(org.tribuo.common.tree.protos.TreeNodeProto value) {
+      if (nodesBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureNodesIsMutable();
+        nodes_.add(value);
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(value);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder addNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto value) {
+      if (nodesBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureNodesIsMutable();
+        nodes_.add(index, value);
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(index, value);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder addNodes(
+        org.tribuo.common.tree.protos.TreeNodeProto.Builder builderForValue) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.add(builderForValue.build());
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder addNodes(
+        int index, org.tribuo.common.tree.protos.TreeNodeProto.Builder builderForValue) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.add(index, builderForValue.build());
+        onChanged();
+      } else {
+        nodesBuilder_.addMessage(index, builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder addAllNodes(
+        java.lang.Iterable<? extends org.tribuo.common.tree.protos.TreeNodeProto> values) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        com.google.protobuf.AbstractMessageLite.Builder.addAll(
+            values, nodes_);
+        onChanged();
+      } else {
+        nodesBuilder_.addAllMessages(values);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder clearNodes() {
+      if (nodesBuilder_ == null) {
+        nodes_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00000001);
+        onChanged();
+      } else {
+        nodesBuilder_.clear();
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public Builder removeNodes(int index) {
+      if (nodesBuilder_ == null) {
+        ensureNodesIsMutable();
+        nodes_.remove(index);
+        onChanged();
+      } else {
+        nodesBuilder_.remove(index);
+      }
+      return this;
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto.Builder getNodesBuilder(
+        int index) {
+      return getNodesFieldBuilder().getBuilder(index);
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder getNodesOrBuilder(
+        int index) {
+      if (nodesBuilder_ == null) {
+        return nodes_.get(index);  } else {
+        return nodesBuilder_.getMessageOrBuilder(index);
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public java.util.List<? extends org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+         getNodesOrBuilderList() {
+      if (nodesBuilder_ != null) {
+        return nodesBuilder_.getMessageOrBuilderList();
+      } else {
+        return java.util.Collections.unmodifiableList(nodes_);
+      }
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto.Builder addNodesBuilder() {
+      return getNodesFieldBuilder().addBuilder(
+          org.tribuo.common.tree.protos.TreeNodeProto.getDefaultInstance());
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public org.tribuo.common.tree.protos.TreeNodeProto.Builder addNodesBuilder(
+        int index) {
+      return getNodesFieldBuilder().addBuilder(
+          index, org.tribuo.common.tree.protos.TreeNodeProto.getDefaultInstance());
+    }
+    /**
+     * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+     */
+    public java.util.List<org.tribuo.common.tree.protos.TreeNodeProto.Builder> 
+         getNodesBuilderList() {
+      return getNodesFieldBuilder().getBuilderList();
+    }
+    private com.google.protobuf.RepeatedFieldBuilderV3<
+        org.tribuo.common.tree.protos.TreeNodeProto, org.tribuo.common.tree.protos.TreeNodeProto.Builder, org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+        getNodesFieldBuilder() {
+      if (nodesBuilder_ == null) {
+        nodesBuilder_ = new com.google.protobuf.RepeatedFieldBuilderV3<
+            org.tribuo.common.tree.protos.TreeNodeProto, org.tribuo.common.tree.protos.TreeNodeProto.Builder, org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder>(
+                nodes_,
+                ((bitField0_ & 0x00000001) != 0),
+                getParentForChildren(),
+                isClean());
+        nodes_ = null;
+      }
+      return nodesBuilder_;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.regression.tree.TreeNodeListProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.regression.tree.TreeNodeListProto)
+  private static final org.tribuo.regression.rtree.protos.TreeNodeListProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.regression.rtree.protos.TreeNodeListProto();
+  }
+
+  public static org.tribuo.regression.rtree.protos.TreeNodeListProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<TreeNodeListProto>
+      PARSER = new com.google.protobuf.AbstractParser<TreeNodeListProto>() {
+    @java.lang.Override
+    public TreeNodeListProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new TreeNodeListProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<TreeNodeListProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<TreeNodeListProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.regression.rtree.protos.TreeNodeListProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProtoOrBuilder.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProtoOrBuilder.java
new file mode 100644
index 000000000..f096e0a8b
--- /dev/null
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TreeNodeListProtoOrBuilder.java
@@ -0,0 +1,33 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-tree.proto
+
+package org.tribuo.regression.rtree.protos;
+
+public interface TreeNodeListProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.regression.tree.TreeNodeListProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  java.util.List<org.tribuo.common.tree.protos.TreeNodeProto> 
+      getNodesList();
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  org.tribuo.common.tree.protos.TreeNodeProto getNodes(int index);
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  int getNodesCount();
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  java.util.List<? extends org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder> 
+      getNodesOrBuilderList();
+  /**
+   * <code>repeated .tribuo.common.tree.TreeNodeProto nodes = 3;</code>
+   */
+  org.tribuo.common.tree.protos.TreeNodeProtoOrBuilder getNodesOrBuilder(
+      int index);
+}
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TribuoRegressionTree.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TribuoRegressionTree.java
new file mode 100644
index 000000000..28f0887dc
--- /dev/null
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/protos/TribuoRegressionTree.java
@@ -0,0 +1,83 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-tree.proto
+
+package org.tribuo.regression.rtree.protos;
+
+public final class TribuoRegressionTree {
+  private TribuoRegressionTree() {}
+  public static void registerAllExtensions(
+      com.google.protobuf.ExtensionRegistryLite registry) {
+  }
+
+  public static void registerAllExtensions(
+      com.google.protobuf.ExtensionRegistry registry) {
+    registerAllExtensions(
+        (com.google.protobuf.ExtensionRegistryLite) registry);
+  }
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_regression_tree_TreeNodeListProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_regression_tree_TreeNodeListProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_NodesEntry_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_NodesEntry_fieldAccessorTable;
+
+  public static com.google.protobuf.Descriptors.FileDescriptor
+      getDescriptor() {
+    return descriptor;
+  }
+  private static  com.google.protobuf.Descriptors.FileDescriptor
+      descriptor;
+  static {
+    java.lang.String[] descriptorData = {
+      "\n\034tribuo-regression-tree.proto\022\026tribuo.r" +
+      "egression.tree\032\021tribuo-core.proto\032\021tribu" +
+      "o-tree.proto\"E\n\021TreeNodeListProto\0220\n\005nod" +
+      "es\030\003 \003(\0132!.tribuo.common.tree.TreeNodePr" +
+      "oto\"\204\002\n#IndependentRegressionTreeModelPr" +
+      "oto\022-\n\010metadata\030\001 \001(\0132\033.tribuo.core.Mode" +
+      "lDataProto\022U\n\005nodes\030\002 \003(\0132F.tribuo.regre" +
+      "ssion.tree.IndependentRegressionTreeMode" +
+      "lProto.NodesEntry\032W\n\nNodesEntry\022\013\n\003key\030\001" +
+      " \001(\t\0228\n\005value\030\002 \001(\0132).tribuo.regression." +
+      "tree.TreeNodeListProto:\0028\001B&\n\"org.tribuo" +
+      ".regression.rtree.protosP\001b\006proto3"
+    };
+    descriptor = com.google.protobuf.Descriptors.FileDescriptor
+      .internalBuildGeneratedFileFrom(descriptorData,
+        new com.google.protobuf.Descriptors.FileDescriptor[] {
+          org.tribuo.protos.core.TribuoCore.getDescriptor(),
+          org.tribuo.common.tree.protos.TribuoTree.getDescriptor(),
+        });
+    internal_static_tribuo_regression_tree_TreeNodeListProto_descriptor =
+      getDescriptor().getMessageTypes().get(0);
+    internal_static_tribuo_regression_tree_TreeNodeListProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_regression_tree_TreeNodeListProto_descriptor,
+        new java.lang.String[] { "Nodes", });
+    internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor =
+      getDescriptor().getMessageTypes().get(1);
+    internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor,
+        new java.lang.String[] { "Metadata", "Nodes", });
+    internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_NodesEntry_descriptor =
+      internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_descriptor.getNestedTypes().get(0);
+    internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_NodesEntry_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_regression_tree_IndependentRegressionTreeModelProto_NodesEntry_descriptor,
+        new java.lang.String[] { "Key", "Value", });
+    org.tribuo.protos.core.TribuoCore.getDescriptor();
+    org.tribuo.common.tree.protos.TribuoTree.getDescriptor();
+  }
+
+  // @@protoc_insertion_point(outer_class_scope)
+}
diff --git a/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto b/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto
index 16cc280bd..2b7770de0 100644
--- a/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto
+++ b/Regression/RegressionTree/src/main/resources/protos/tribuo-regression-tree.proto
@@ -22,10 +22,7 @@ syntax = "proto3";
 package tribuo.regression.tree;
 
 option java_multiple_files = true;
-option java_package = "org.tribuo.regression.tree.protos";
-
-// We use any to encode polymorphism
-import "google/protobuf/any.proto";
+option java_package = "org.tribuo.regression.rtree.protos";
 
 // Import Tribuo's core protos
 import "tribuo-core.proto";
@@ -37,7 +34,7 @@ import "tribuo-tree.proto";
 Carrier for a list of tree nodes.
  */
 message TreeNodeListProto {
-  repeated TreeNodeProto nodes = 3;
+  repeated tribuo.common.tree.TreeNodeProto nodes = 3;
 }
 
 /*
diff --git a/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTJointRegressionTrainer.java b/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTJointRegressionTrainer.java
index 25dfe0235..0c8915369 100644
--- a/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTJointRegressionTrainer.java
+++ b/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTJointRegressionTrainer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -63,6 +63,7 @@ public void testDenseData() {
         Pair<Dataset<Regressor>, Dataset<Regressor>> p = RegressionDataGenerator.denseTrainTest();
         Model<Regressor> model = testJointRegressionTree(p, t);
         Helpers.testModelSerialization(model, Regressor.class);
+        Helpers.testModelProtoSerialization(model, Regressor.class, p.getB());
     }
 
     @Test
@@ -244,6 +245,7 @@ public void testThreeDenseData() {
         assertEquals(expectedDim2, llEval.r2(new Regressor(RegressionDataGenerator.secondDimensionName, Double.NaN)), 1e-6);
         assertEquals(expectedDim3, llEval.r2(new Regressor(RegressionDataGenerator.thirdDimensionName, Double.NaN)), 1e-6);
         assertEquals(expectedAve, llEval.averageR2(), 1e-6);
+        Helpers.testModelProtoSerialization(llModel, Regressor.class, p.getB());
 
         p = RegressionDataGenerator.threeDimDenseTrainTest(1.0, true);
         llModel = t.train(p.getA());
diff --git a/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTRegressionTrainer.java b/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTRegressionTrainer.java
index 0357d6289..2851376a9 100644
--- a/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTRegressionTrainer.java
+++ b/Regression/RegressionTree/src/test/java/org/tribuo/regression/rtree/TestCARTRegressionTrainer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -54,6 +54,7 @@ public static Model<Regressor> testIndependentRegressionTree(Pair<Dataset<Regres
         features = m.getTopFeatures(-1);
         Assertions.assertNotNull(features);
         Assertions.assertFalse(features.isEmpty());
+        Helpers.testModelProtoSerialization(m, Regressor.class, p.getB());
         return m;
     }
 
@@ -204,6 +205,7 @@ public void testThreeDenseData() {
         assertEquals(expectedDim2,llEval.r2(new Regressor(RegressionDataGenerator.secondDimensionName,Double.NaN)),1e-6);
         assertEquals(expectedDim3,llEval.r2(new Regressor(RegressionDataGenerator.thirdDimensionName,Double.NaN)),1e-6);
         assertEquals(expectedAve,llEval.averageR2(),1e-6);
+        Helpers.testModelProtoSerialization(llModel, Regressor.class, p.getB());
 
         p = RegressionDataGenerator.threeDimDenseTrainTest(1.0, true);
         llModel = t.train(p.getA());

From c30e70f15d0a89ff1d2bf926aadfbc23694d43a3 Mon Sep 17 00:00:00 2001
From: Adam Pocock <adam.pocock@oracle.com>
Date: Wed, 14 Sep 2022 21:45:28 -0400
Subject: [PATCH 3/7] Adding separate serialization for a dimension tuple to
 make the trees happy.

---
 .../java/org/tribuo/regression/Regressor.java |  33 +
 .../protos/DimensionTupleProto.java           | 697 ++++++++++++++++++
 .../protos/DimensionTupleProtoOrBuilder.java  |  33 +
 .../protos/TribuoRegressionCore.java          |  55 +-
 .../protos/tribuo-regression-core.proto       |  10 +-
 5 files changed, 806 insertions(+), 22 deletions(-)
 create mode 100644 Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProto.java
 create mode 100644 Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProtoOrBuilder.java

diff --git a/Regression/Core/src/main/java/org/tribuo/regression/Regressor.java b/Regression/Core/src/main/java/org/tribuo/regression/Regressor.java
index 0ed6bde11..fad52a0af 100644
--- a/Regression/Core/src/main/java/org/tribuo/regression/Regressor.java
+++ b/Regression/Core/src/main/java/org/tribuo/regression/Regressor.java
@@ -24,6 +24,7 @@
 import org.tribuo.Output;
 import org.tribuo.OutputInfo;
 import org.tribuo.protos.core.OutputProto;
+import org.tribuo.regression.protos.DimensionTupleProto;
 import org.tribuo.regression.protos.RegressorProto;
 import org.tribuo.util.Util;
 
@@ -575,6 +576,20 @@ public DimensionTuple(String name, double value) {
             this(name,value,Double.NaN);
         }
 
+        /**
+         * Deserialization factory.
+         * @param version The serialized object version.
+         * @param className The class name.
+         * @param message The serialized data.
+         */
+        public static DimensionTuple deserializeFromProto(int version, String className, Any message) throws InvalidProtocolBufferException {
+            if (version < 0 || version > 0) {
+                throw new IllegalArgumentException("Unknown version " + version + ", this class supports at most version " + 0);
+            }
+            DimensionTupleProto proto = message.unpack(DimensionTupleProto.class);
+            return new DimensionTuple(proto.getName(),proto.getValue(),proto.getVariance());
+        }
+
         @Override
         public int size() {
             return 1;
@@ -685,6 +700,24 @@ public int hashCode() {
         public String getDimensionNamesString() {
             return name;
         }
+
+        @Override
+        public OutputProto serialize() {
+            OutputProto.Builder outputBuilder = OutputProto.newBuilder();
+
+            outputBuilder.setClassName(DimensionTuple.class.getName());
+            outputBuilder.setVersion(0);
+
+            DimensionTupleProto.Builder data = DimensionTupleProto.newBuilder();
+            data.setName(name);
+            data.setValue(value);
+            data.setVariance(variance);
+
+            outputBuilder.setSerializedData(Any.pack(data.build()));
+
+            return outputBuilder.build();
+        }
+
     }
 
     private class RegressorIterator implements Iterator<DimensionTuple> {
diff --git a/Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProto.java b/Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProto.java
new file mode 100644
index 000000000..0751320ae
--- /dev/null
+++ b/Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProto.java
@@ -0,0 +1,697 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-core.proto
+
+package org.tribuo.regression.protos;
+
+/**
+ * <pre>
+ *Regressor.DimensionTuple proto
+ * </pre>
+ *
+ * Protobuf type {@code tribuo.regression.DimensionTupleProto}
+ */
+public final class DimensionTupleProto extends
+    com.google.protobuf.GeneratedMessageV3 implements
+    // @@protoc_insertion_point(message_implements:tribuo.regression.DimensionTupleProto)
+    DimensionTupleProtoOrBuilder {
+private static final long serialVersionUID = 0L;
+  // Use DimensionTupleProto.newBuilder() to construct.
+  private DimensionTupleProto(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+  private DimensionTupleProto() {
+    name_ = "";
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(
+      UnusedPrivateParameter unused) {
+    return new DimensionTupleProto();
+  }
+
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet
+  getUnknownFields() {
+    return this.unknownFields;
+  }
+  private DimensionTupleProto(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 10: {
+            java.lang.String s = input.readStringRequireUtf8();
+
+            name_ = s;
+            break;
+          }
+          case 17: {
+
+            value_ = input.readDouble();
+            break;
+          }
+          case 25: {
+
+            variance_ = input.readDouble();
+            break;
+          }
+          default: {
+            if (!parseUnknownField(
+                input, unknownFields, extensionRegistry, tag)) {
+              done = true;
+            }
+            break;
+          }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(
+          e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+  public static final com.google.protobuf.Descriptors.Descriptor
+      getDescriptor() {
+    return org.tribuo.regression.protos.TribuoRegressionCore.internal_static_tribuo_regression_DimensionTupleProto_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return org.tribuo.regression.protos.TribuoRegressionCore.internal_static_tribuo_regression_DimensionTupleProto_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            org.tribuo.regression.protos.DimensionTupleProto.class, org.tribuo.regression.protos.DimensionTupleProto.Builder.class);
+  }
+
+  public static final int NAME_FIELD_NUMBER = 1;
+  private volatile java.lang.Object name_;
+  /**
+   * <code>string name = 1;</code>
+   * @return The name.
+   */
+  @java.lang.Override
+  public java.lang.String getName() {
+    java.lang.Object ref = name_;
+    if (ref instanceof java.lang.String) {
+      return (java.lang.String) ref;
+    } else {
+      com.google.protobuf.ByteString bs = 
+          (com.google.protobuf.ByteString) ref;
+      java.lang.String s = bs.toStringUtf8();
+      name_ = s;
+      return s;
+    }
+  }
+  /**
+   * <code>string name = 1;</code>
+   * @return The bytes for name.
+   */
+  @java.lang.Override
+  public com.google.protobuf.ByteString
+      getNameBytes() {
+    java.lang.Object ref = name_;
+    if (ref instanceof java.lang.String) {
+      com.google.protobuf.ByteString b = 
+          com.google.protobuf.ByteString.copyFromUtf8(
+              (java.lang.String) ref);
+      name_ = b;
+      return b;
+    } else {
+      return (com.google.protobuf.ByteString) ref;
+    }
+  }
+
+  public static final int VALUE_FIELD_NUMBER = 2;
+  private double value_;
+  /**
+   * <code>double value = 2;</code>
+   * @return The value.
+   */
+  @java.lang.Override
+  public double getValue() {
+    return value_;
+  }
+
+  public static final int VARIANCE_FIELD_NUMBER = 3;
+  private double variance_;
+  /**
+   * <code>double variance = 3;</code>
+   * @return The variance.
+   */
+  @java.lang.Override
+  public double getVariance() {
+    return variance_;
+  }
+
+  private byte memoizedIsInitialized = -1;
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output)
+                      throws java.io.IOException {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
+      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(value_) != 0) {
+      output.writeDouble(2, value_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(variance_) != 0) {
+      output.writeDouble(3, variance_);
+    }
+    unknownFields.writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
+      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(value_) != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeDoubleSize(2, value_);
+    }
+    if (java.lang.Double.doubleToRawLongBits(variance_) != 0) {
+      size += com.google.protobuf.CodedOutputStream
+        .computeDoubleSize(3, variance_);
+    }
+    size += unknownFields.getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+     return true;
+    }
+    if (!(obj instanceof org.tribuo.regression.protos.DimensionTupleProto)) {
+      return super.equals(obj);
+    }
+    org.tribuo.regression.protos.DimensionTupleProto other = (org.tribuo.regression.protos.DimensionTupleProto) obj;
+
+    if (!getName()
+        .equals(other.getName())) return false;
+    if (java.lang.Double.doubleToLongBits(getValue())
+        != java.lang.Double.doubleToLongBits(
+            other.getValue())) return false;
+    if (java.lang.Double.doubleToLongBits(getVariance())
+        != java.lang.Double.doubleToLongBits(
+            other.getVariance())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + NAME_FIELD_NUMBER;
+    hash = (53 * hash) + getName().hashCode();
+    hash = (37 * hash) + VALUE_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashLong(
+        java.lang.Double.doubleToLongBits(getValue()));
+    hash = (37 * hash) + VARIANCE_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashLong(
+        java.lang.Double.doubleToLongBits(getVariance()));
+    hash = (29 * hash) + unknownFields.hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      java.nio.ByteBuffer data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      java.nio.ByteBuffer data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      byte[] data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseDelimitedFrom(java.io.InputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseDelimitedFrom(
+      java.io.InputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseDelimitedWithIOException(PARSER, input, extensionRegistry);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      com.google.protobuf.CodedInputStream input)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input);
+  }
+  public static org.tribuo.regression.protos.DimensionTupleProto parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3
+        .parseWithIOException(PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() { return newBuilder(); }
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+  public static Builder newBuilder(org.tribuo.regression.protos.DimensionTupleProto prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE
+        ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(
+      com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   * <pre>
+   *Regressor.DimensionTuple proto
+   * </pre>
+   *
+   * Protobuf type {@code tribuo.regression.DimensionTupleProto}
+   */
+  public static final class Builder extends
+      com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
+      // @@protoc_insertion_point(builder_implements:tribuo.regression.DimensionTupleProto)
+      org.tribuo.regression.protos.DimensionTupleProtoOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor
+        getDescriptor() {
+      return org.tribuo.regression.protos.TribuoRegressionCore.internal_static_tribuo_regression_DimensionTupleProto_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return org.tribuo.regression.protos.TribuoRegressionCore.internal_static_tribuo_regression_DimensionTupleProto_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              org.tribuo.regression.protos.DimensionTupleProto.class, org.tribuo.regression.protos.DimensionTupleProto.Builder.class);
+    }
+
+    // Construct using org.tribuo.regression.protos.DimensionTupleProto.newBuilder()
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
+
+    private Builder(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+      maybeForceBuilderInitialization();
+    }
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3
+              .alwaysUseFieldBuilders) {
+      }
+    }
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      name_ = "";
+
+      value_ = 0D;
+
+      variance_ = 0D;
+
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor
+        getDescriptorForType() {
+      return org.tribuo.regression.protos.TribuoRegressionCore.internal_static_tribuo_regression_DimensionTupleProto_descriptor;
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.protos.DimensionTupleProto getDefaultInstanceForType() {
+      return org.tribuo.regression.protos.DimensionTupleProto.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.protos.DimensionTupleProto build() {
+      org.tribuo.regression.protos.DimensionTupleProto result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public org.tribuo.regression.protos.DimensionTupleProto buildPartial() {
+      org.tribuo.regression.protos.DimensionTupleProto result = new org.tribuo.regression.protos.DimensionTupleProto(this);
+      result.name_ = name_;
+      result.value_ = value_;
+      result.variance_ = variance_;
+      onBuilt();
+      return result;
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.setField(field, value);
+    }
+    @java.lang.Override
+    public Builder clearField(
+        com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+    @java.lang.Override
+    public Builder clearOneof(
+        com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field,
+        java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof org.tribuo.regression.protos.DimensionTupleProto) {
+        return mergeFrom((org.tribuo.regression.protos.DimensionTupleProto)other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(org.tribuo.regression.protos.DimensionTupleProto other) {
+      if (other == org.tribuo.regression.protos.DimensionTupleProto.getDefaultInstance()) return this;
+      if (!other.getName().isEmpty()) {
+        name_ = other.name_;
+        onChanged();
+      }
+      if (other.getValue() != 0D) {
+        setValue(other.getValue());
+      }
+      if (other.getVariance() != 0D) {
+        setVariance(other.getVariance());
+      }
+      this.mergeUnknownFields(other.unknownFields);
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      org.tribuo.regression.protos.DimensionTupleProto parsedMessage = null;
+      try {
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (org.tribuo.regression.protos.DimensionTupleProto) e.getUnfinishedMessage();
+        throw e.unwrapIOException();
+      } finally {
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
+      return this;
+    }
+
+    private java.lang.Object name_ = "";
+    /**
+     * <code>string name = 1;</code>
+     * @return The name.
+     */
+    public java.lang.String getName() {
+      java.lang.Object ref = name_;
+      if (!(ref instanceof java.lang.String)) {
+        com.google.protobuf.ByteString bs =
+            (com.google.protobuf.ByteString) ref;
+        java.lang.String s = bs.toStringUtf8();
+        name_ = s;
+        return s;
+      } else {
+        return (java.lang.String) ref;
+      }
+    }
+    /**
+     * <code>string name = 1;</code>
+     * @return The bytes for name.
+     */
+    public com.google.protobuf.ByteString
+        getNameBytes() {
+      java.lang.Object ref = name_;
+      if (ref instanceof String) {
+        com.google.protobuf.ByteString b = 
+            com.google.protobuf.ByteString.copyFromUtf8(
+                (java.lang.String) ref);
+        name_ = b;
+        return b;
+      } else {
+        return (com.google.protobuf.ByteString) ref;
+      }
+    }
+    /**
+     * <code>string name = 1;</code>
+     * @param value The name to set.
+     * @return This builder for chaining.
+     */
+    public Builder setName(
+        java.lang.String value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  
+      name_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>string name = 1;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearName() {
+      
+      name_ = getDefaultInstance().getName();
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>string name = 1;</code>
+     * @param value The bytes for name to set.
+     * @return This builder for chaining.
+     */
+    public Builder setNameBytes(
+        com.google.protobuf.ByteString value) {
+      if (value == null) {
+    throw new NullPointerException();
+  }
+  checkByteStringIsUtf8(value);
+      
+      name_ = value;
+      onChanged();
+      return this;
+    }
+
+    private double value_ ;
+    /**
+     * <code>double value = 2;</code>
+     * @return The value.
+     */
+    @java.lang.Override
+    public double getValue() {
+      return value_;
+    }
+    /**
+     * <code>double value = 2;</code>
+     * @param value The value to set.
+     * @return This builder for chaining.
+     */
+    public Builder setValue(double value) {
+      
+      value_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>double value = 2;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearValue() {
+      
+      value_ = 0D;
+      onChanged();
+      return this;
+    }
+
+    private double variance_ ;
+    /**
+     * <code>double variance = 3;</code>
+     * @return The variance.
+     */
+    @java.lang.Override
+    public double getVariance() {
+      return variance_;
+    }
+    /**
+     * <code>double variance = 3;</code>
+     * @param value The variance to set.
+     * @return This builder for chaining.
+     */
+    public Builder setVariance(double value) {
+      
+      variance_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     * <code>double variance = 3;</code>
+     * @return This builder for chaining.
+     */
+    public Builder clearVariance() {
+      
+      variance_ = 0D;
+      onChanged();
+      return this;
+    }
+    @java.lang.Override
+    public final Builder setUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+
+    // @@protoc_insertion_point(builder_scope:tribuo.regression.DimensionTupleProto)
+  }
+
+  // @@protoc_insertion_point(class_scope:tribuo.regression.DimensionTupleProto)
+  private static final org.tribuo.regression.protos.DimensionTupleProto DEFAULT_INSTANCE;
+  static {
+    DEFAULT_INSTANCE = new org.tribuo.regression.protos.DimensionTupleProto();
+  }
+
+  public static org.tribuo.regression.protos.DimensionTupleProto getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<DimensionTupleProto>
+      PARSER = new com.google.protobuf.AbstractParser<DimensionTupleProto>() {
+    @java.lang.Override
+    public DimensionTupleProto parsePartialFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return new DimensionTupleProto(input, extensionRegistry);
+    }
+  };
+
+  public static com.google.protobuf.Parser<DimensionTupleProto> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<DimensionTupleProto> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public org.tribuo.regression.protos.DimensionTupleProto getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+
+}
+
diff --git a/Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProtoOrBuilder.java b/Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProtoOrBuilder.java
new file mode 100644
index 000000000..535f00ded
--- /dev/null
+++ b/Regression/Core/src/main/java/org/tribuo/regression/protos/DimensionTupleProtoOrBuilder.java
@@ -0,0 +1,33 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: tribuo-regression-core.proto
+
+package org.tribuo.regression.protos;
+
+public interface DimensionTupleProtoOrBuilder extends
+    // @@protoc_insertion_point(interface_extends:tribuo.regression.DimensionTupleProto)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   * <code>string name = 1;</code>
+   * @return The name.
+   */
+  java.lang.String getName();
+  /**
+   * <code>string name = 1;</code>
+   * @return The bytes for name.
+   */
+  com.google.protobuf.ByteString
+      getNameBytes();
+
+  /**
+   * <code>double value = 2;</code>
+   * @return The value.
+   */
+  double getValue();
+
+  /**
+   * <code>double variance = 3;</code>
+   * @return The variance.
+   */
+  double getVariance();
+}
diff --git a/Regression/Core/src/main/java/org/tribuo/regression/protos/TribuoRegressionCore.java b/Regression/Core/src/main/java/org/tribuo/regression/protos/TribuoRegressionCore.java
index a244784c0..bc116a996 100644
--- a/Regression/Core/src/main/java/org/tribuo/regression/protos/TribuoRegressionCore.java
+++ b/Regression/Core/src/main/java/org/tribuo/regression/protos/TribuoRegressionCore.java
@@ -19,6 +19,11 @@ public static void registerAllExtensions(
   static final 
     com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
       internal_static_tribuo_regression_RegressorProto_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+    internal_static_tribuo_regression_DimensionTupleProto_descriptor;
+  static final 
+    com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_tribuo_regression_DimensionTupleProto_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
     internal_static_tribuo_regression_RegressionFactoryProto_descriptor;
   static final 
@@ -51,23 +56,25 @@ public static void registerAllExtensions(
       "\n\034tribuo-regression-core.proto\022\021tribuo.r" +
       "egression\032\021tribuo-core.proto\"?\n\016Regresso" +
       "rProto\022\014\n\004name\030\001 \003(\t\022\r\n\005value\030\002 \003(\001\022\020\n\010v" +
-      "ariance\030\003 \003(\001\"+\n\026RegressionFactoryProto\022" +
-      "\021\n\tsplitChar\030\001 \001(\t\"\242\001\n\032MutableRegression" +
-      "InfoProto\022\r\n\005label\030\001 \003(\t\022\r\n\005count\030\002 \003(\003\022" +
-      "\013\n\003max\030\003 \003(\001\022\013\n\003min\030\004 \003(\001\022\014\n\004mean\030\005 \003(\001\022" +
-      "\022\n\nsumSquares\030\006 \003(\001\022\024\n\014unknownCount\030\007 \001(" +
-      "\005\022\024\n\014overallCount\030\010 \001(\003\"\260\001\n\034ImmutableReg" +
-      "ressionInfoProto\022\r\n\005label\030\001 \003(\t\022\r\n\005count" +
-      "\030\002 \003(\003\022\n\n\002id\030\003 \003(\005\022\013\n\003max\030\004 \003(\001\022\013\n\003min\030\005" +
-      " \003(\001\022\014\n\004mean\030\006 \003(\001\022\022\n\nsumSquares\030\007 \003(\001\022\024" +
-      "\n\014unknownCount\030\010 \001(\005\022\024\n\014overallCount\030\t \001" +
-      "(\003\"\321\001\n\031DummyRegressionModelProto\022-\n\010meta" +
-      "data\030\001 \001(\0132\033.tribuo.core.ModelDataProto\022" +
-      "\022\n\ndummy_type\030\002 \001(\t\022(\n\006output\030\003 \001(\0132\030.tr" +
-      "ibuo.core.OutputProto\022\014\n\004seed\030\004 \001(\003\022\r\n\005m" +
-      "eans\030\005 \003(\001\022\021\n\tvariances\030\006 \003(\001\022\027\n\017dimensi" +
-      "on_names\030\007 \003(\tB \n\034org.tribuo.regression." +
-      "protosP\001b\006proto3"
+      "ariance\030\003 \003(\001\"D\n\023DimensionTupleProto\022\014\n\004" +
+      "name\030\001 \001(\t\022\r\n\005value\030\002 \001(\001\022\020\n\010variance\030\003 " +
+      "\001(\001\"+\n\026RegressionFactoryProto\022\021\n\tsplitCh" +
+      "ar\030\001 \001(\t\"\242\001\n\032MutableRegressionInfoProto\022" +
+      "\r\n\005label\030\001 \003(\t\022\r\n\005count\030\002 \003(\003\022\013\n\003max\030\003 \003" +
+      "(\001\022\013\n\003min\030\004 \003(\001\022\014\n\004mean\030\005 \003(\001\022\022\n\nsumSqua" +
+      "res\030\006 \003(\001\022\024\n\014unknownCount\030\007 \001(\005\022\024\n\014overa" +
+      "llCount\030\010 \001(\003\"\260\001\n\034ImmutableRegressionInf" +
+      "oProto\022\r\n\005label\030\001 \003(\t\022\r\n\005count\030\002 \003(\003\022\n\n\002" +
+      "id\030\003 \003(\005\022\013\n\003max\030\004 \003(\001\022\013\n\003min\030\005 \003(\001\022\014\n\004me" +
+      "an\030\006 \003(\001\022\022\n\nsumSquares\030\007 \003(\001\022\024\n\014unknownC" +
+      "ount\030\010 \001(\005\022\024\n\014overallCount\030\t \001(\003\"\321\001\n\031Dum" +
+      "myRegressionModelProto\022-\n\010metadata\030\001 \001(\013" +
+      "2\033.tribuo.core.ModelDataProto\022\022\n\ndummy_t" +
+      "ype\030\002 \001(\t\022(\n\006output\030\003 \001(\0132\030.tribuo.core." +
+      "OutputProto\022\014\n\004seed\030\004 \001(\003\022\r\n\005means\030\005 \003(\001" +
+      "\022\021\n\tvariances\030\006 \003(\001\022\027\n\017dimension_names\030\007" +
+      " \003(\tB \n\034org.tribuo.regression.protosP\001b\006" +
+      "proto3"
     };
     descriptor = com.google.protobuf.Descriptors.FileDescriptor
       .internalBuildGeneratedFileFrom(descriptorData,
@@ -80,26 +87,32 @@ public static void registerAllExtensions(
       com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_tribuo_regression_RegressorProto_descriptor,
         new java.lang.String[] { "Name", "Value", "Variance", });
-    internal_static_tribuo_regression_RegressionFactoryProto_descriptor =
+    internal_static_tribuo_regression_DimensionTupleProto_descriptor =
       getDescriptor().getMessageTypes().get(1);
+    internal_static_tribuo_regression_DimensionTupleProto_fieldAccessorTable = new
+      com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+        internal_static_tribuo_regression_DimensionTupleProto_descriptor,
+        new java.lang.String[] { "Name", "Value", "Variance", });
+    internal_static_tribuo_regression_RegressionFactoryProto_descriptor =
+      getDescriptor().getMessageTypes().get(2);
     internal_static_tribuo_regression_RegressionFactoryProto_fieldAccessorTable = new
       com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_tribuo_regression_RegressionFactoryProto_descriptor,
         new java.lang.String[] { "SplitChar", });
     internal_static_tribuo_regression_MutableRegressionInfoProto_descriptor =
-      getDescriptor().getMessageTypes().get(2);
+      getDescriptor().getMessageTypes().get(3);
     internal_static_tribuo_regression_MutableRegressionInfoProto_fieldAccessorTable = new
       com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_tribuo_regression_MutableRegressionInfoProto_descriptor,
         new java.lang.String[] { "Label", "Count", "Max", "Min", "Mean", "SumSquares", "UnknownCount", "OverallCount", });
     internal_static_tribuo_regression_ImmutableRegressionInfoProto_descriptor =
-      getDescriptor().getMessageTypes().get(3);
+      getDescriptor().getMessageTypes().get(4);
     internal_static_tribuo_regression_ImmutableRegressionInfoProto_fieldAccessorTable = new
       com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_tribuo_regression_ImmutableRegressionInfoProto_descriptor,
         new java.lang.String[] { "Label", "Count", "Id", "Max", "Min", "Mean", "SumSquares", "UnknownCount", "OverallCount", });
     internal_static_tribuo_regression_DummyRegressionModelProto_descriptor =
-      getDescriptor().getMessageTypes().get(4);
+      getDescriptor().getMessageTypes().get(5);
     internal_static_tribuo_regression_DummyRegressionModelProto_fieldAccessorTable = new
       com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
         internal_static_tribuo_regression_DummyRegressionModelProto_descriptor,
diff --git a/Regression/Core/src/main/resources/protos/tribuo-regression-core.proto b/Regression/Core/src/main/resources/protos/tribuo-regression-core.proto
index b8111ca1b..b2ae6baa7 100644
--- a/Regression/Core/src/main/resources/protos/tribuo-regression-core.proto
+++ b/Regression/Core/src/main/resources/protos/tribuo-regression-core.proto
@@ -27,7 +27,6 @@ option java_package = "org.tribuo.regression.protos";
 // Import Tribuo's core protos
 import "tribuo-core.proto";
 
-
 /*
 Regressor proto
  */
@@ -37,6 +36,15 @@ message RegressorProto {
   repeated double variance = 3;
 }
 
+/*
+Regressor.DimensionTuple proto
+ */
+message DimensionTupleProto {
+  string name = 1;
+  double value = 2;
+  double variance = 3;
+}
+
 /*
 RegressionFactory proto
  */

From f9d09ea7180b0292b6a157ef970d62d3bfc8d82e Mon Sep 17 00:00:00 2001
From: Adam Pocock <adam.pocock@oracle.com>
Date: Wed, 14 Sep 2022 21:45:50 -0400
Subject: [PATCH 4/7] Adding full tree serialization and more tests.

---
 .../tribuo/classification/dtree/TestCART.java |  18 ++-
 .../common/tree/AbstractCARTTrainer.java      |   6 +-
 .../org/tribuo/common/tree/SplitNode.java     |   3 +
 .../org/tribuo/common/tree/TreeModel.java     | 107 ++++++++++++++----
 .../rtree/IndependentRegressionTreeModel.java |   3 +-
 5 files changed, 110 insertions(+), 27 deletions(-)

diff --git a/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java b/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java
index 347491aaa..7ada19600 100644
--- a/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java
+++ b/Classification/DecisionTree/src/test/java/org/tribuo/classification/dtree/TestCART.java
@@ -44,7 +44,7 @@ public class TestCART {
     private static final CARTClassificationTrainer randomt = new CARTClassificationTrainer(5,2, 0.0f,1.0f, true,
             new GiniIndex(), Trainer.DEFAULT_SEED);
 
-    public static Model<Label> testCART(Pair<Dataset<Label>,Dataset<Label>> p, CARTClassificationTrainer trainer) {
+    public static TreeModel<Label> testCART(Pair<Dataset<Label>,Dataset<Label>> p, CARTClassificationTrainer trainer) {
         TreeModel<Label> m = trainer.train(p.getA());
         LabelEvaluator e = new LabelEvaluator();
         LabelEvaluation evaluation = e.evaluate(m,p.getB());
@@ -81,7 +81,7 @@ public void testRandomSingleClassTraining() {
         runSingleClassTraining(randomt);
     }
 
-    public Model<Label> runDenseData(CARTClassificationTrainer trainer) {
+    public static TreeModel<Label> runDenseData(CARTClassificationTrainer trainer) {
         Pair<Dataset<Label>,Dataset<Label>> p = LabelledDataGenerator.denseTrainTest();
         return testCART(p, trainer);
     }
@@ -92,6 +92,20 @@ public void testDenseData() {
         Helpers.testModelSerialization(model,Label.class);
     }
 
+    @Test
+    public void testDecisionStump() {
+        CARTClassificationTrainer stumpTrainer = new CARTClassificationTrainer(1);
+        TreeModel<Label> model = runDenseData(stumpTrainer);
+        assertEquals(3,model.countNodes(model.getRoot()));
+    }
+
+    @Test
+    public void testMajorityPrediction() {
+        CARTClassificationTrainer stumpTrainer = new CARTClassificationTrainer(0);
+        TreeModel<Label> model = runDenseData(stumpTrainer);
+        assertEquals(1,model.countNodes(model.getRoot()));
+    }
+
     @Test
     public void testRandomDenseData() {
         runDenseData(randomt);
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/AbstractCARTTrainer.java b/Common/Trees/src/main/java/org/tribuo/common/tree/AbstractCARTTrainer.java
index ef3f5e66f..35b5ac0be 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/AbstractCARTTrainer.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/AbstractCARTTrainer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -126,8 +126,8 @@ public synchronized void postConfig() {
             throw new IllegalArgumentException("minImpurityDecrease must be greater than or equal to 0");
         }
 
-        if (maxDepth < 1) {
-            throw new IllegalArgumentException("maxDepth must be greater than or equal to 1");
+        if (maxDepth < 0) {
+            throw new IllegalArgumentException("maxDepth must be non-negative");
         }
 
         if (minChildWeight <= 0.0f) {
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java b/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
index 2ad55a1a2..4d0a3904b 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
@@ -223,6 +223,9 @@ boolean canBuild() {
         }
 
         SplitNode<T> build() {
+            if (!canBuild()) {
+                throw new IllegalStateException("Not ready to build this split node, missing the children pointers");
+            }
             return new SplitNode<>(splitValue,splitFeature,impurity,greaterThan,lessThanOrEqual);
         }
 
diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
index e7a029188..a153453b1 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
@@ -32,14 +32,13 @@
 import org.tribuo.common.tree.protos.TreeModelProto;
 import org.tribuo.common.tree.protos.TreeNodeProto;
 import org.tribuo.impl.ModelDataCarrier;
-import org.tribuo.math.la.DenseSparseMatrix;
 import org.tribuo.math.la.SparseVector;
-import org.tribuo.math.la.Tensor;
 import org.tribuo.protos.core.ModelProto;
 import org.tribuo.provenance.ModelProvenance;
 
 import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -129,15 +128,14 @@ private static Node<?> deserializeNodeProto(TreeNodeProto proto) throws InvalidP
         int version = proto.getVersion();
         String className = proto.getClassName();
         Any message = proto.getSerializedData();
-        String type = message.getTypeUrl();
-        if (type.equals(SplitNodeProto.getDescriptor().getFullName())) {
+        if (message.is(SplitNodeProto.class)) {
             SplitNodeProto splitProto = message.unpack(SplitNodeProto.class);
             return new SplitNode.SplitNodeBuilder<>(splitProto);
-        } else if (type.equals(LeafNodeProto.getDescriptor().getFullName())) {
+        } else if (message.is(LeafNodeProto.class)) {
             LeafNodeProto leafProto = message.unpack(LeafNodeProto.class);
             return new LeafNode.LeafNodeBuilder<>(leafProto);
         } else {
-            throw new IllegalStateException("Invalid protobuf, expected leaf or split node, found " + type);
+            throw new IllegalStateException("Invalid protobuf, expected leaf or split node, found " + message.getTypeUrl());
         }
     }
 
@@ -165,34 +163,42 @@ protected static <U extends Output<U>> List<Node<U>> deserializeFromProtos(List<
         }
 
         while (!nodeQueue.isEmpty()) {
-            Node<U> node = nodeQueue.poll();
-            int parentIdx = -1;
+            Node<U> nodeBuilder = nodeQueue.poll();
+            int curIdx = -1;
             Node<U> parent = null;
             Node<U> builtNode = null;
-            if (node instanceof LeafNode.LeafNodeBuilder) {
+            if (nodeBuilder instanceof LeafNode.LeafNodeBuilder) {
                 // build leaf node
-                LeafNode.LeafNodeBuilder<U> builder = (LeafNode.LeafNodeBuilder<U>) node;
+                LeafNode.LeafNodeBuilder<U> builder = (LeafNode.LeafNodeBuilder<U>) nodeBuilder;
                 LeafNode<U> leaf = builder.build();
                 nodes.set(builder.getCurIdx(), leaf);
                 builtNode = leaf;
+                curIdx = builder.getCurIdx();
                 // update parent
-                parentIdx = builder.getParentIdx();
-                parent = nodes.get(parentIdx);
-            } else if (node instanceof SplitNode.SplitNodeBuilder) {
-                SplitNode.SplitNodeBuilder<U> builder = (SplitNode.SplitNodeBuilder<U>) node;
+                int parentIdx = builder.getParentIdx();
+                if (parentIdx != -1) {
+                    parent = nodes.get(parentIdx);
+                }
+            } else if (nodeBuilder instanceof SplitNode.SplitNodeBuilder) {
+                // build split node now the childred are ready
+                SplitNode.SplitNodeBuilder<U> builder = (SplitNode.SplitNodeBuilder<U>) nodeBuilder;
                 SplitNode<U> split = builder.build();
                 nodes.set(builder.getCurIdx(), split);
                 builtNode = split;
-                parentIdx = builder.getParentIdx();
+                curIdx = builder.getCurIdx();
+                // update parent
+                int parentIdx = builder.getParentIdx();
                 if (parentIdx != -1) {
                     parent = nodes.get(parentIdx);
                 }
+            } else {
+                throw new IllegalStateException("Invalid protobuf, found a constructed node was added to the build queue, found " + nodeBuilder.getClass());
             }
             if (parent instanceof SplitNode.SplitNodeBuilder) {
                 SplitNode.SplitNodeBuilder<U> splitBuilder = (SplitNode.SplitNodeBuilder<U>) parent;
-                if (parentIdx == splitBuilder.getGreaterThanIdx()) {
+                if (curIdx == splitBuilder.getGreaterThanIdx()) {
                     splitBuilder.setGreaterThan(builtNode);
-                } else if (parentIdx == splitBuilder.getLessThanOrEqualIdx()) {
+                } else if (curIdx == splitBuilder.getLessThanOrEqualIdx()) {
                     splitBuilder.setLessThanOrEqualIdx(builtNode);
                 } else {
                     throw new IllegalStateException("Invalid protobuf, found a child node which didn't map into a parent");
@@ -211,7 +217,7 @@ protected static <U extends Output<U>> List<Node<U>> deserializeFromProtos(List<
                 throw new IllegalStateException("Invalid protobuf, found unbuilt node, " + node);
             } else if (node instanceof LeafNode) {
                 U cur = ((LeafNode<U>) node).getOutput();
-                if (!cur.getClass().equals(outputClass)) {
+                if (!outputClass.isAssignableFrom(cur.getClass())) {
                     throw new IllegalStateException("Invalid protobuf, node output did not match output domain, found " + cur.getClass() + ", expected " + outputClass);
                 }
             }
@@ -411,6 +417,32 @@ public Set<String> getFeatures() {
         return features;
     }
 
+    /**
+     * Counts the number of nodes in the tree rooted at the supplied node, including that node.
+     * @param root The tree root.
+     * @return The number of nodes.
+     */
+    public int countNodes(Node<T> root) {
+        Queue<Node<T>> nodeQueue = new LinkedList<>();
+
+        int counter = 0;
+        nodeQueue.offer(root);
+
+        while (!nodeQueue.isEmpty()) {
+            Node<T> node = nodeQueue.poll();
+            if (node != null) {
+                counter++;
+                if (!node.isLeaf()) {
+                    SplitNode<T> splitNode = (SplitNode<T>) node;
+                    nodeQueue.offer(splitNode.getGreaterThan());
+                    nodeQueue.offer(splitNode.getLessThanOrEqual());
+                }
+            }
+        }
+
+        return counter;
+    }
+
     @Override
     public String toString() {
         return "TreeModel(description="+provenance.toString()+",\n\t\ttree="+root.toString()+")";
@@ -441,9 +473,44 @@ public ModelProto serialize() {
     }
 
     protected List<TreeNodeProto> serializeToNodes(Node<T> root) {
-        List<TreeNodeProto> protos = new ArrayList<>();
+        int numNodes = countNodes(root);
+        TreeNodeProto[] protos = new TreeNodeProto[numNodes];
 
-        return protos;
+        int counter = 0;
+        Queue<SerializationState<T>> nodeQueue = new ArrayDeque<>();
+        nodeQueue.offer(new SerializationState<>(-1,counter,root));
+        while (!nodeQueue.isEmpty()) {
+            SerializationState<T> state = nodeQueue.poll();
+            if (state.node instanceof SplitNode) {
+                SplitNode<T> node = (SplitNode<T>) state.node;
+                int greaterIdx = ++counter;
+                int lessIdx = ++counter;
+                TreeNodeProto proto = node.serialize(state.parentIdx, state.curIdx, greaterIdx, lessIdx);
+                protos[state.curIdx] = proto;
+                nodeQueue.offer(new SerializationState<>(state.curIdx, greaterIdx, node.getGreaterThan()));
+                nodeQueue.offer(new SerializationState<>(state.curIdx, lessIdx, node.getLessThanOrEqual()));
+            } else if (state.node instanceof LeafNode) {
+                LeafNode<T> node = (LeafNode<T>) state.node;
+                TreeNodeProto proto = node.serialize(state.parentIdx, state.curIdx);
+                protos[state.curIdx] = proto;
+            } else {
+                throw new IllegalStateException("Invalid tree structure, contained a node which wasn't a SplitNode or a LeafNode, found " + state.node.getClass());
+            }
+        }
+
+        return Arrays.asList(protos);
+    }
+
+    private static final class SerializationState<T extends Output<T>> {
+        final int parentIdx;
+        final int curIdx;
+        final Node<T> node;
+
+        SerializationState(int parentIdx, int curIdx, Node<T> node) {
+            this.parentIdx = parentIdx;
+            this.curIdx = curIdx;
+            this.node = node;
+        }
     }
 
     static abstract class NodeBuilder {
diff --git a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java
index 03f12a598..acdd3b866 100644
--- a/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java
+++ b/Regression/RegressionTree/src/main/java/org/tribuo/regression/rtree/IndependentRegressionTreeModel.java
@@ -29,7 +29,6 @@
 import org.tribuo.common.tree.Node;
 import org.tribuo.common.tree.SplitNode;
 import org.tribuo.common.tree.TreeModel;
-import org.tribuo.common.tree.protos.TreeModelProto;
 import org.tribuo.common.tree.protos.TreeNodeProto;
 import org.tribuo.impl.ModelDataCarrier;
 import org.tribuo.math.la.SparseVector;
@@ -376,7 +375,7 @@ public ModelProto serialize() {
 
         ModelProto.Builder builder = ModelProto.newBuilder();
         builder.setSerializedData(Any.pack(modelBuilder.build()));
-        builder.setClassName(TreeModel.class.getName());
+        builder.setClassName(IndependentRegressionTreeModel.class.getName());
         builder.setVersion(CURRENT_VERSION);
 
         return builder.build();

From 045f5743511882bfa8d23e89dedabbc08991d29d Mon Sep 17 00:00:00 2001
From: Philip Ogren <philip.ogren@oracle.com>
Date: Mon, 3 Oct 2022 10:47:34 -0600
Subject: [PATCH 5/7] change name from SplitNode.setLessThanOrEqualIdx to
 setLessThanOrEqual

---
 .../Trees/src/main/java/org/tribuo/common/tree/SplitNode.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java b/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
index 4d0a3904b..b126fb501 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/SplitNode.java
@@ -237,7 +237,7 @@ void setGreaterThan(Node<T> greaterThan) {
             }
         }
 
-        void setLessThanOrEqualIdx(Node<T> lessThanOrEqual) {
+        void setLessThanOrEqual(Node<T> lessThanOrEqual) {
             if (this.lessThanOrEqual == null) {
                 this.lessThanOrEqual = lessThanOrEqual;
             } else {

From 8734bc2527d3275729cd01466a40ad2d776959d6 Mon Sep 17 00:00:00 2001
From: Philip Ogren <philip.ogren@oracle.com>
Date: Mon, 3 Oct 2022 10:49:37 -0600
Subject: [PATCH 6/7] added comments to TreeModel.deserializeFromProtos

---
 .../java/org/tribuo/common/tree/TreeModel.java     | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
index a153453b1..480848ed2 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
@@ -140,7 +140,17 @@ private static Node<?> deserializeNodeProto(TreeNodeProto proto) throws InvalidP
     }
 
     /**
-     * Deserializes a list of node protos into a list of nodes, with the root in the first element.
+     * We will start off with a list of node builders that we will replace item-by-item with the nodes
+     * that they built.  We will start with the leaf nodes and add split nodes as they become ready
+     * to build.  In this way we will travel up the tree and only attempt to build split nodes when
+     * both of their child nodes are available.  It may seem a bit tortured to do it this way, but this
+     * approach preserves the immutability of the built nodes (the split nodes in particular).  The split node
+     * builder only knows the index of its children when it is deserialized but must be given the actual
+     * nodes before their build method can be called.  Note that we only add split node builders to the queue
+     * once they can be built because both children have been created and provided to the builder.
+     * <p>
+     * This approach should traverse the entire tree in the correct order but we check at the end of the method
+     * that everything looks good.  
      * @param nodeProtos The node protos to deserialize.
      * @return The nodes.
      * @throws InvalidProtocolBufferException If an unexpected proto is found.
@@ -199,7 +209,7 @@ protected static <U extends Output<U>> List<Node<U>> deserializeFromProtos(List<
                 if (curIdx == splitBuilder.getGreaterThanIdx()) {
                     splitBuilder.setGreaterThan(builtNode);
                 } else if (curIdx == splitBuilder.getLessThanOrEqualIdx()) {
-                    splitBuilder.setLessThanOrEqualIdx(builtNode);
+                    splitBuilder.setLessThanOrEqual(builtNode);
                 } else {
                     throw new IllegalStateException("Invalid protobuf, found a child node which didn't map into a parent");
                 }

From 5ea3a7fff4b72a9751140b9597d4f81d93a8287d Mon Sep 17 00:00:00 2001
From: Adam Pocock <adam.pocock@oracle.com>
Date: Mon, 3 Oct 2022 13:10:10 -0400
Subject: [PATCH 7/7] Update TreeModel.java

Fix typo
---
 .../Trees/src/main/java/org/tribuo/common/tree/TreeModel.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
index 480848ed2..73b3762ac 100644
--- a/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
+++ b/Common/Trees/src/main/java/org/tribuo/common/tree/TreeModel.java
@@ -190,7 +190,7 @@ protected static <U extends Output<U>> List<Node<U>> deserializeFromProtos(List<
                     parent = nodes.get(parentIdx);
                 }
             } else if (nodeBuilder instanceof SplitNode.SplitNodeBuilder) {
-                // build split node now the childred are ready
+                // build split node now the children are ready
                 SplitNode.SplitNodeBuilder<U> builder = (SplitNode.SplitNodeBuilder<U>) nodeBuilder;
                 SplitNode<U> split = builder.build();
                 nodes.set(builder.getCurIdx(), split);