[BUG] Use the Correct WG Communicator (#4548)

cuGraph-PyG's WholeFeatureStore currently uses the local communicator, when it should be using the global communicator, as was originally intended.  This PR modifies the feature store so it correctly calls `get_global_node_communicator()`.

This also fixes another bug where torch.int32 was used to store the number of edges in the graph, which resulted in an overflow error when the number of edges exceeded that datatype's maximum value.  The datatype is now correctly set to int64.

Authors:
  - Alex Barghi (https://github.com/alexbarghi-nv)

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

URL: #4548

python/cugraph-pyg/cugraph_pyg/data/feature_store.py

@@ -169,7 +169,7 @@ def __init__(self, memory_type="distributed", location="cpu"):
 
         self.__features = {}
 
-        self.__wg_comm = wgth.get_local_node_communicator()
+        self.__wg_comm = wgth.get_global_communicator()
         self.__wg_type = memory_type
         self.__wg_location = location
 

python/cugraph-pyg/cugraph_pyg/data/graph_store.py

@@ -271,7 +271,7 @@ def __get_edgelist(self):
             torch.tensor(
                 [self.__edge_indices[et].shape[1] for et in sorted_keys],
                 device="cuda",
-                dtype=torch.int32,
+                dtype=torch.int64,
             )
         )