diff --git a/repeng/extract.py b/repeng/extract.py
index 4c1330a..55de4b0 100644
--- a/repeng/extract.py
+++ b/repeng/extract.py
@@ -1,4 +1,5 @@
 import dataclasses
+import os
 import typing
 import warnings
 
@@ -31,6 +32,22 @@ def train(
         dataset: list[DatasetEntry],
         **kwargs,
     ) -> "ControlVector":
+        """
+        Train a ControlVector for a given model and tokenizer using the provided dataset.
+
+        Args:
+            model (PreTrainedModel | ControlModel): The model to train against.
+            tokenizer (PreTrainedTokenizerBase): The tokenizer to tokenize the dataset.
+            dataset (list[DatasetEntry]): The dataset used for training.
+            **kwargs: Additional keyword arguments.
+                max_batch_size (int, optional): The maximum batch size for training.
+                    Defaults to 32. Try reducing this if you're running out of memory.
+                method (str, optional): The training method to use. Can be either
+                    "pca_diff" or "pca_center". Defaults to "pca_diff".
+
+        Returns:
+            ControlVector: The trained vector.
+        """
         dirs = read_representations(
             model,
             tokenizer,
@@ -39,7 +56,7 @@ def train(
         )
         return cls(model_type=model.config.model_type, directions=dirs)
 
-    def export_gguf(self, path: str):
+    def export_gguf(self, path: os.PathLike[str] | str):
         """
         Export a trained ControlVector to a llama.cpp .gguf file.
         Note: This file can't be used with llama.cpp yet. WIP!
@@ -62,6 +79,39 @@ def export_gguf(self, path: str):
         writer.write_tensors_to_file()
         writer.close()
 
+    @classmethod
+    def import_gguf(cls, path: os.PathLike[str] | str) -> "ControlVector":
+        reader = gguf.GGUFReader(path)
+
+        archf = reader.get_field("general.architecture")
+        if not archf or not len(archf.parts):
+            warnings.warn(".gguf file missing architecture field")
+        else:
+            arch = str(bytes(archf.parts[-1]), encoding="utf-8", errors="replace")
+            if arch != "controlvector":
+                warnings.warn(
+                    f".gguf file with architecture {arch!r} does not appear to be a control vector!"
+                )
+
+        modelf = reader.get_field("controlvector.model_hint")
+        if not modelf or not len(modelf.parts):
+            raise ValueError(".gguf file missing controlvector.model_hint field")
+        model_hint = str(bytes(modelf.parts[-1]), encoding="utf-8")
+
+        directions = {}
+        for tensor in reader.tensors:
+            if not tensor.name.startswith("direction."):
+                continue
+            try:
+                layer = int(tensor.name.split(".")[1])
+            except:
+                raise ValueError(
+                    f".gguf file has invalid direction field name: {tensor.name}"
+                )
+            directions[layer] = tensor.data
+
+        return cls(model_type=model_hint, directions=directions)
+
     def _helper_combine(
         self, other: "ControlVector", other_coeff: float
     ) -> "ControlVector":
@@ -82,6 +132,19 @@ def _helper_combine(
                 directions[layer] = other_layer
         return ControlVector(model_type=model_type, directions=directions)
 
+    def __eq__(self, other: "ControlVector") -> bool:
+        if self is other:
+            return True
+
+        if self.model_type != other.model_type:
+            return False
+        if self.directions.keys() != other.directions.keys():
+            return False
+        for k in self.directions.keys():
+            if (self.directions[k] != other.directions[k]).any():
+                return False
+        return True
+
     def __add__(self, other: "ControlVector") -> "ControlVector":
         if not isinstance(other, ControlVector):
             raise TypeError(
@@ -121,11 +184,11 @@ def read_representations(
     inputs: list[DatasetEntry],
     hidden_layers: typing.Iterable[int] | None = None,
     batch_size: int = 32,
+    method: typing.Literal["pca_diff", "pca_center", "umap"] = "pca_diff",
 ) -> dict[int, np.ndarray]:
     """
     Extract the representations based on the contrast dataset.
     """
-
     if not hidden_layers:
         hidden_layers = range(-1, -model.config.num_hidden_layers, -1)
 
@@ -140,31 +203,39 @@ def read_representations(
         model, tokenizer, train_strs, hidden_layers, batch_size
     )
 
-    # get differences between (positive, negative) pairs
-    relative_layer_hiddens = {}
-    for layer in hidden_layers:
-        relative_layer_hiddens[layer] = (
-            layer_hiddens[layer][::2] - layer_hiddens[layer][1::2]
-        )
-
     # get directions for each layer using PCA
     directions: dict[int, np.ndarray] = {}
     for layer in tqdm.tqdm(hidden_layers):
-        assert layer_hiddens[layer].shape[0] == len(inputs) * 2
-
-        # fit layer directions
-        train = np.vstack(
-            relative_layer_hiddens[layer]
-            - relative_layer_hiddens[layer].mean(axis=0, keepdims=True)
-        )
-        pca_model = PCA(n_components=1, whiten=False).fit(train)
-        # shape (n_features,)
-        directions[layer] = pca_model.components_.astype(np.float32).squeeze(axis=0)
+        h = layer_hiddens[layer]
+        assert h.shape[0] == len(inputs) * 2
+
+        if method == "pca_diff":
+            train = h[::2] - h[1::2]
+        elif method == "pca_center":
+            center = (h[::2] + h[1::2]) / 2
+            train = h
+            train[::2] -= center
+            train[1::2] -= center
+        elif method == "umap":
+            train = h
+        else:
+            raise ValueError("unknown method " + method)
+
+        if method != "umap":
+            # shape (1, n_features)
+            pca_model = PCA(n_components=1, whiten=False).fit(train)
+            # shape (n_features,)
+            directions[layer] = pca_model.components_.astype(np.float32).squeeze(axis=0)
+        else:
+            # still experimental so don't want to add this as a real dependency yet
+            import umap  # type: ignore
+
+            umap_model = umap.UMAP(n_components=1)
+            embedding = umap_model.fit_transform(train).astype(np.float32)
+            directions[layer] = np.sum(train * embedding, axis=0) / np.sum(embedding)
 
         # calculate sign
-        projected_hiddens = project_onto_direction(
-            layer_hiddens[layer], directions[layer]
-        )
+        projected_hiddens = project_onto_direction(h, directions[layer])
 
         # order is [positive, negative, positive, negative, ...]
         positive_smaller_mean = np.mean(
diff --git a/repeng/tests.py b/repeng/tests.py
index 233e28f..b0441fc 100644
--- a/repeng/tests.py
+++ b/repeng/tests.py
@@ -1,22 +1,143 @@
 import functools
 import json
 import pathlib
+import tempfile
 
-import torch
 from transformers import AutoModelForCausalLM, AutoTokenizer, PreTrainedTokenizerBase
 
 from . import ControlModel, ControlVector, DatasetEntry
+from .control import model_layer_list
+
+
+def test_layer_list():
+    _, gpt2 = load_gpt2_model()
+    assert len(model_layer_list(gpt2)) == 12
+    _, lts = load_llama_tinystories_model()
+    assert len(model_layer_list(lts)) == 4
+
+
+def test_round_trip_gguf():
+    tokenizer, model = load_llama_tinystories_model()
+    suffixes = load_suffixes()[:50]  # truncate to train vector faster
+    happy_dataset = make_dataset(
+        "She saw a {persona}",
+        ["mushroom"],
+        ["cat"],
+        suffixes,
+    )
+    mushroom_cat_vector = ControlVector.train(
+        model, tokenizer, happy_dataset, method="pca_center"
+    )
+
+    with tempfile.NamedTemporaryFile("wb") as f:
+        mushroom_cat_vector.export_gguf(f.name)
+        read = ControlVector.import_gguf(f.name)
+        # no need to use allclose because we're just dumping exact bytes, no rounding
+        assert mushroom_cat_vector == read
+
+
+def test_train_gpt2():
+    tokenizer, model = load_gpt2_model()
+    suffixes = load_suffixes()[:50]  # truncate to train vector faster
+    happy_dataset = make_dataset(
+        "You are feeling extremely {persona}.",
+        ["happy", "joyful"],
+        ["sad", "miserable"],
+        suffixes,
+    )
+    happy_vector = ControlVector.train(
+        model, tokenizer, happy_dataset, method="pca_center"
+    )
+
+    def gen(vector: ControlVector | None, strength_coeff: float | None = None):
+        return model_generate(
+            "You are feeling", model, tokenizer, vector, strength_coeff
+        )
+
+    baseline = gen(None)
+    happy = gen(20 * happy_vector)
+    sad = gen(-50 * happy_vector)
+
+    print("baseline:", baseline)
+    print("   happy:", happy)
+    print("     sad:", sad)
+
+    assert baseline == "You are feeling a little bit of an anxiety"
+    # these should be identical
+    assert baseline == gen(happy_vector, 0.0)
+    assert baseline == gen(happy_vector * 0.0)
+    assert baseline == gen(happy_vector - happy_vector)
+
+    assert happy == "You are feeling great and happy. I'm"
+    # these should be identical
+    assert happy == gen(happy_vector, 20.0)
+    assert happy == gen(happy_vector * 20)
+    assert happy == gen(-(happy_vector * -20))
+
+    assert sad == "You are feeling the worst,\n—("
+
+
+def test_train_llama_tinystories():
+    tokenizer, model = load_llama_tinystories_model()
+    suffixes = load_suffixes()[:50]  # truncate to train vector faster
+    happy_dataset = make_dataset(
+        "She saw a {persona}",
+        ["mushroom"],
+        ["cat"],
+        suffixes,
+    )
+    mushroom_cat_vector = ControlVector.train(
+        model, tokenizer, happy_dataset, method="pca_center"
+    )
+
+    prompt = "Once upon a time, a little girl named Lily saw a"
+
+    def gen(vector: ControlVector | None, strength_coeff: float | None = None):
+        return model_generate(
+            prompt,
+            model,
+            tokenizer,
+            vector,
+            strength_coeff,
+            max_new_tokens=3,
+        )
+
+    baseline = gen(None).removeprefix("<s> ")
+    mushroom = gen(100 * mushroom_cat_vector).removeprefix("<s> ")
+    cat = gen(-100 * mushroom_cat_vector).removeprefix("<s> ")
+
+    print("baseline:", baseline)
+    print("mushroom:", mushroom)
+    print("     cat:", cat)
+
+    assert baseline.removeprefix(prompt) == " big, red"
+    assert mushroom.removeprefix(prompt) == " small plant."
+    assert cat.removeprefix(prompt) == " cat Bud guitar"
+
+
+################################################################################
+# Helpers
+################################################################################
+
+
+@functools.lru_cache(maxsize=1)
+def load_gpt2_model() -> tuple[PreTrainedTokenizerBase, ControlModel]:
+    return load_model("openai-community/gpt2", list(range(-2, -8, -1)))
 
 
 @functools.lru_cache(maxsize=1)
-def load_model() -> tuple[PreTrainedTokenizerBase, ControlModel]:
-    model_name = "openai-community/gpt2"
+def load_llama_tinystories_model() -> tuple[PreTrainedTokenizerBase, ControlModel]:
+    return load_model("Mxode/TinyStories-LLaMA2-25M-256h-4l-GQA", [2, 3])
 
+
+def load_model(
+    model_name: str, layers: list[int]
+) -> tuple[PreTrainedTokenizerBase, ControlModel]:
     tokenizer = AutoTokenizer.from_pretrained(model_name)
     tokenizer.pad_token_id = tokenizer.eos_token_id
     model = AutoModelForCausalLM.from_pretrained(model_name)
     model = model.to("cpu")
-    return (tokenizer, ControlModel(model, list(range(-2, -8, -1))))
+    return (tokenizer, ControlModel(model, layers))
 
 
 def model_generate(
@@ -25,7 +146,7 @@ def model_generate(
     tokenizer: PreTrainedTokenizerBase,
     vector: ControlVector | None,
     strength_coeff: float | None = None,
-    max_new_tokens: int = 20,
+    max_new_tokens: int = 6,
 ) -> str:
     input_ids = tokenizer(input, return_tensors="pt").to(model.device)
     if vector is not None and strength_coeff is not None:
@@ -57,8 +178,8 @@ def make_dataset(
         ):
             dataset.append(
                 DatasetEntry(
-                    positive=template.format(persona=negative_persona) + f" {suffix}",
-                    negative=template.format(persona=positive_persona) + f" {suffix}",
+                    positive=template.format(persona=positive_persona) + f" {suffix}",
+                    negative=template.format(persona=negative_persona) + f" {suffix}",
                 )
             )
     return dataset
@@ -76,45 +197,3 @@ def project_root() -> pathlib.Path:
         if (parent / "pyproject.toml").exists():
             return parent
     raise RuntimeError("couldn't find project root")
-
-
-def test_train():
-    tokenizer, model = load_model()
-    suffixes = load_suffixes()[:50]  # truncate to train vector faster
-    happy_dataset = make_dataset(
-        "*I am a {persona} person making statements about the world.*",
-        ["happy", "joyful"],
-        ["sad", "miserable"],
-        suffixes,
-    )
-    happy_vector = ControlVector.train(model, tokenizer, happy_dataset)
-
-    baseline = model_generate("I am", model, tokenizer, None)
-    print("baseline:", baseline)
-    assert (
-        baseline
-        == "I am not a fan of the idea that you can't have an open source project without having some kind or"
-    )
-    # these should be identical
-    assert baseline == model_generate("I am", model, tokenizer, happy_vector, 0.0)
-    assert baseline == model_generate("I am", model, tokenizer, happy_vector * 0.0)
-    assert baseline == model_generate(
-        "I am", model, tokenizer, happy_vector - happy_vector
-    )
-
-    happy = model_generate("I am", model, tokenizer, 10 * happy_vector)
-    print("happy:", happy)
-    assert (
-        happy
-        == "I am also excited to announce that we will be hosting a special event on the first day of our new year"
-    )
-    # should be identical
-    assert happy == model_generate("I am", model, tokenizer, happy_vector * 10)
-    assert happy == model_generate("I am", model, tokenizer, -(happy_vector * -10))
-
-    sad = model_generate("I am", model, tokenizer, -15 * happy_vector)
-    print("sad:", sad)
-    assert (
-        sad
-        == "I am a fucking idiot. I'm not even trying to get you out of here, but if it's"
-    )