Add options to extract_subgraph() to bypass renumbering and adding …

…edge_data, exclude internal `_WEIGHT_` column from `edge_property_names`, added `num_vertices_with_properties` attr (#2419)

Add options to `extract_subgraph()` to bypass renumbering and adding edge_data, exclude internal `_WEIGHT_` column from `edge_property_names`.

Also added a new attribute `num_vertices_with_properties` which returns the number of vertices with properties, which is different than the number of vertices, since vertices can be added via `add_edge_data()`.  This is needed for GNN use cases which need to know how many verts have properties which can be accessed (this corresponds to the number of rows in the internal vertex prop data table).

Added unit tests to verify new `extract_subgraph()` options work, the new `num_vertices_with_properties` attribute, and `_WEIGHT_` columns names aren't included, for both SG and MG versions.

closes #2418 
closes #2410

Authors:
  - Rick Ratzel (https://github.com/rlratzel)

Approvers:
  - Alex Barghi (https://github.com/alexbarghi-nv)
  - Erik Welch (https://github.com/eriknw)
  - Brad Rees (https://github.com/BradReesWork)

URL: #2419

python/cugraph/cugraph/dask/structure/mg_property_graph.py

@@ -126,6 +126,7 @@ def __init__(self, num_workers=None):
 
         # Cached property values
         self.__num_vertices = None
+        self.__num_vertices_with_properties = None
 
         # number of gpu's to use
         if num_workers is None:
@@ -145,6 +146,18 @@ def num_vertices(self):
                 self.__num_vertices = vert_count.compute()
         return self.__num_vertices
 
+    @property
+    def num_vertices_with_properties(self):
+        if self.__num_vertices_with_properties is not None:
+            return self.__num_vertices_with_properties
+
+        if self.__vertex_prop_dataframe is not None:
+            self.__num_vertices_with_properties = \
+                len(self.__vertex_prop_dataframe)
+            return self.__num_vertices_with_properties
+
+        return 0
+
     @property
     def num_edges(self):
         if self.__edge_prop_dataframe is not None:
@@ -156,7 +169,8 @@ def num_edges(self):
     def edges(self):
         if self.__edge_prop_dataframe is not None:
             return self.__edge_prop_dataframe[[self.src_col_name,
-                                               self.dst_col_name]]
+                                               self.dst_col_name,
+                                               self.edge_id_col_name]]
         return None
 
     @property
@@ -176,6 +190,8 @@ def edge_property_names(self):
             props.remove(self.dst_col_name)
             props.remove(self.edge_id_col_name)
             props.remove(self.type_col_name)  # should "type" be removed?
+            if self.weight_col_name in props:
+                props.remove(self.weight_col_name)
             return props
         return []
 
@@ -260,9 +276,10 @@ def add_vertex_data(self,
                                  "found in dataframe: "
                                  f"{list(invalid_columns)}")
 
-        # Clear the cached value for num_vertices since more could be added in
-        # this method.
+        # Clear the cached values related to the number of vertices since more
+        # could be added in this method.
         self.__num_vertices = None
+        self.__num_vertices_with_properties = None
 
         # Initialize the __vertex_prop_dataframe if necessary using the same
         # type as the incoming dataframe.
@@ -373,7 +390,7 @@ def add_edge_data(self,
                                  f"{list(invalid_columns)}")
 
         # Clear the cached value for num_vertices since more could be added in
-        # this method.
+        # this method. This method cannot affect num_vertices_with_properties
         self.__num_vertices = None
 
         default_edge_columns = [self.src_col_name,
@@ -467,7 +484,9 @@ def extract_subgraph(self,
                          selection=None,
                          edge_weight_property=None,
                          default_edge_weight=None,
-                         allow_multi_edges=False
+                         allow_multi_edges=False,
+                         renumber_graph=True,
+                         add_edge_data=True
                          ):
         """
         Return a subgraph of the overall PropertyGraph containing vertices
@@ -495,7 +514,13 @@ def extract_subgraph(self,
         allow_multi_edges : bool
             If True, multiple edges should be used to create the return Graph,
             otherwise multiple edges will be detected and an exception raised.
-
+        renumber_graph : bool (default is True)
+            If True, return a Graph that has been renumbered for use by graph
+            algorithms. If False, the returned graph will need to be manually
+            renumbered prior to calling graph algos.
+        add_edge_data : bool (default is True)
+            If True, add meta data about the edges contained in the extracted
+            graph which are required for future calls to annotate_dataframe().
         Returns
         -------
         A Graph instance of the same type as create_using containing only the
@@ -556,7 +581,9 @@ def extract_subgraph(self,
             create_using=create_using,
             edge_weight_property=edge_weight_property,
             default_edge_weight=default_edge_weight,
-            allow_multi_edges=allow_multi_edges)
+            allow_multi_edges=allow_multi_edges,
+            renumber_graph=renumber_graph,
+            add_edge_data=add_edge_data)
 
     def annotate_dataframe(self, df, G, edge_vertex_col_names):
         raise NotImplementedError()
@@ -566,7 +593,9 @@ def edge_props_to_graph(self,
                             create_using,
                             edge_weight_property=None,
                             default_edge_weight=None,
-                            allow_multi_edges=False):
+                            allow_multi_edges=False,
+                            renumber_graph=True,
+                            add_edge_data=True):
         """
         Create and return a Graph from the edges in edge_prop_df.
         """
@@ -594,10 +623,8 @@ def edge_props_to_graph(self,
         # If a default_edge_weight was specified but an edge_weight_property
         # was not, a new edge weight column must be added.
         elif default_edge_weight:
-            edge_attr = self.__gen_unique_name(edge_prop_df.columns,
-                                               prefix=self.weight_col_name)
+            edge_attr = self.weight_col_name
             edge_prop_df[edge_attr] = default_edge_weight
-
         else:
             edge_attr = None
 
@@ -630,18 +657,43 @@ def edge_props_to_graph(self,
                 msg = "default Graph graph type"
             raise RuntimeError("query resulted in duplicate edges which "
                                f"cannot be represented with the {msg}")
-        G.from_dask_cudf_edgelist(
-                                   edge_prop_df,
-                                   source=self.src_col_name,
-                                   destination=self.dst_col_name,
-                                   edge_attr=edge_attr, renumber=True)
-        # Set the edge_data on the resulting Graph to a DataFrame containing
-        # the edges and the edge ID for each. Edge IDs are needed for future
-        # calls to annotate_dataframe() in order to associate edges with their
-        # properties, since the PG can contain multiple edges between vertrices
-        # with different properties.
-        G.edge_data = self.__create_property_lookup_table(edge_prop_df)
-        # FIXME: also add vertex_data
+
+        # FIXME: MNMG Graphs required renumber to be True due to requirements
+        # on legacy code that needed segment offsets, partition offsets,
+        # etc. which were previously computed during the "legacy" C
+        # renumbering.  The workaround is to pass renumber=True, then manually
+        # call G.compute_renumber_edge_list(legacy_renum_only=True) to compute
+        # the required meta-data without changing vertex IDs.
+        if renumber_graph is False:
+            renumber = True
+        else:
+            renumber = renumber_graph
+
+        col_names = [self.src_col_name, self.dst_col_name]
+        if edge_attr is not None:
+            col_names.append(edge_attr)
+
+        G.from_dask_cudf_edgelist(edge_prop_df[col_names],
+                                  source=self.src_col_name,
+                                  destination=self.dst_col_name,
+                                  edge_attr=edge_attr,
+                                  renumber=renumber)
+        # FIXME: see FIXME above - to generate the edgelist,
+        # compute_renumber_edge_list() must be called, but legacy mode needs to
+        # be used based on if renumbering was to be done or not.
+        if renumber_graph is False:
+            G.compute_renumber_edge_list(legacy_renum_only=True)
+        else:
+            G.compute_renumber_edge_list(legacy_renum_only=False)
+
+        if add_edge_data:
+            # Set the edge_data on the resulting Graph to a DataFrame
+            # containing the edges and the edge ID for each. Edge IDs are
+            # needed for future calls to annotate_dataframe() in order to
+            # associate edges with their properties, since the PG can contain
+            # multiple edges between vertrices with different properties.
+            # FIXME: also add vertex_data
+            G.edge_data = self.__create_property_lookup_table(edge_prop_df)
 
         return G
 
@@ -684,18 +736,6 @@ def __get_all_vertices_series(self):
             vert_sers.append(epd[self.dst_col_name])
         return vert_sers
 
-    @staticmethod
-    def __gen_unique_name(current_names, prefix="col"):
-        """
-        Helper function to generate a currently unused name.
-        """
-        name = prefix
-        counter = 2
-        while name in current_names:
-            name = f"{prefix}{counter}"
-            counter += 1
-        return name
-
     @staticmethod
     def __get_new_column_dtypes(from_df, to_df):
         """

python/cugraph/cugraph/structure/property_graph.py

@@ -135,6 +135,7 @@ def __init__(self):
 
         # Cached property values
         self.__num_vertices = None
+        self.__num_vertices_with_properties = None
 
     # PropertyGraph read-only attributes
     @property
@@ -152,6 +153,18 @@ def num_vertices(self):
 
         return self.__num_vertices
 
+    @property
+    def num_vertices_with_properties(self):
+        if self.__num_vertices_with_properties is not None:
+            return self.__num_vertices_with_properties
+
+        if self.__vertex_prop_dataframe is not None:
+            self.__num_vertices_with_properties = \
+                len(self.__vertex_prop_dataframe)
+            return self.__num_vertices_with_properties
+
+        return 0
+
     @property
     def num_edges(self):
         if self.__edge_prop_dataframe is not None:
@@ -183,6 +196,8 @@ def edge_property_names(self):
             props.remove(self.dst_col_name)
             props.remove(self.edge_id_col_name)
             props.remove(self.type_col_name)  # should "type" be removed?
+            if self.weight_col_name in props:
+                props.remove(self.weight_col_name)
             return props
         return []
 
@@ -278,9 +293,10 @@ def add_vertex_data(self,
                                 "the PropertyGraph was already initialized "
                                 f"using type {self.__dataframe_type}")
 
-        # Clear the cached value for num_vertices since more could be added in
-        # this method.
+        # Clear the cached values related to the number of vertices since more
+        # could be added in this method.
         self.__num_vertices = None
+        self.__num_vertices_with_properties = None
 
         # Initialize the __vertex_prop_dataframe if necessary using the same
         # type as the incoming dataframe.
@@ -400,7 +416,7 @@ def add_edge_data(self,
                                 f"using type {self.__dataframe_type}")
 
         # Clear the cached value for num_vertices since more could be added in
-        # this method.
+        # this method. This method cannot affect num_vertices_with_properties
         self.__num_vertices = None
 
         default_edge_columns = [self.src_col_name,
@@ -551,7 +567,9 @@ def extract_subgraph(self,
                          selection=None,
                          edge_weight_property=None,
                          default_edge_weight=None,
-                         allow_multi_edges=False
+                         allow_multi_edges=False,
+                         renumber_graph=True,
+                         add_edge_data=True
                          ):
         """
         Return a subgraph of the overall PropertyGraph containing vertices
@@ -579,6 +597,13 @@ def extract_subgraph(self,
         allow_multi_edges : bool
             If True, multiple edges should be used to create the return Graph,
             otherwise multiple edges will be detected and an exception raised.
+        renumber_graph : bool (default is True)
+            If True, return a Graph that has been renumbered for use by graph
+            algorithms. If False, the returned graph will need to be manually
+            renumbered prior to calling graph algos.
+        add_edge_data : bool (default is True)
+            If True, add meta data about the edges contained in the extracted
+            graph which are required for future calls to annotate_dataframe().
 
         Returns
         -------
@@ -641,7 +666,9 @@ def extract_subgraph(self,
             create_using=create_using,
             edge_weight_property=edge_weight_property,
             default_edge_weight=default_edge_weight,
-            allow_multi_edges=allow_multi_edges)
+            allow_multi_edges=allow_multi_edges,
+            renumber_graph=renumber_graph,
+            add_edge_data=add_edge_data)
 
     def annotate_dataframe(self, df, G, edge_vertex_col_names):
         """
@@ -713,7 +740,9 @@ def edge_props_to_graph(self,
                             create_using,
                             edge_weight_property=None,
                             default_edge_weight=None,
-                            allow_multi_edges=False):
+                            allow_multi_edges=False,
+                            renumber_graph=True,
+                            add_edge_data=True):
         """
         Create and return a Graph from the edges in edge_prop_df.
         """
@@ -742,10 +771,8 @@ def edge_props_to_graph(self,
         # If a default_edge_weight was specified but an edge_weight_property
         # was not, a new edge weight column must be added.
         elif default_edge_weight:
-            edge_attr = self.__gen_unique_name(edge_prop_df.columns,
-                                               prefix=self.weight_col_name)
+            edge_attr = self.weight_col_name
             edge_prop_df[edge_attr] = default_edge_weight
-
         else:
             edge_attr = None
 
@@ -782,20 +809,21 @@ def edge_props_to_graph(self,
         create_args = {"source": self.src_col_name,
                        "destination": self.dst_col_name,
                        "edge_attr": edge_attr,
-                       "renumber": True,
+                       "renumber": renumber_graph,
                        }
         if type(edge_prop_df) is cudf.DataFrame:
             G.from_cudf_edgelist(edge_prop_df, **create_args)
         else:
             G.from_pandas_edgelist(edge_prop_df, **create_args)
 
-        # Set the edge_data on the resulting Graph to a DataFrame containing
-        # the edges and the edge ID for each. Edge IDs are needed for future
-        # calls to annotate_dataframe() in order to associate edges with their
-        # properties, since the PG can contain multiple edges between vertrices
-        # with different properties.
-        G.edge_data = self.__create_property_lookup_table(edge_prop_df)
-        # FIXME: also add vertex_data
+        if add_edge_data:
+            # Set the edge_data on the resulting Graph to a DataFrame
+            # containing the edges and the edge ID for each. Edge IDs are
+            # needed for future calls to annotate_dataframe() in order to
+            # associate edges with their properties, since the PG can contain
+            # multiple edges between vertrices with different properties.
+            # FIXME: also add vertex_data
+            G.edge_data = self.__create_property_lookup_table(edge_prop_df)
 
         return G
 
@@ -862,18 +890,6 @@ def __get_all_vertices_series(self):
             vert_sers.append(epd[self.dst_col_name])
         return vert_sers
 
-    @staticmethod
-    def __gen_unique_name(current_names, prefix="col"):
-        """
-        Helper function to generate a currently unused name.
-        """
-        name = prefix
-        counter = 2
-        while name in current_names:
-            name = f"{prefix}{counter}"
-            counter += 1
-        return name
-
     @staticmethod
     def __get_new_column_dtypes(from_df, to_df):
         """

python/cugraph/cugraph/tests/conftest.py

@@ -58,10 +58,7 @@ def dask_client():
     yield client
 
     Comms.destroy()
-    # Shut down the connected scheduler and workers
-    # therefore we will no longer rely on killing the dask cluster ID
-    # for MNMG runs
-    client.shutdown()
+    client.close()
     if cluster:
         cluster.close()
     print("\ndask_client fixture: client.close() called")