dgl.distributed.edge_split

dgl.distributed.edge_split(edges, partition_book=None, rank=None, force_even=True)[source]

Split edges and return a subset for the local rank.

This function splits the input edges based on the partition book and returns a subset of edges for the local rank. This method is used for dividing workloads for distributed training.

The input edges can be stored as a vector of masks. The length of the vector is the same as the number of edges in a graph; 1 indicates that the edge in the corresponding location exists.

There are two strategies to split the edges. By default, it splits the edges in a way to maximize data locality. That is, all edges that belong to a process are returned. If force_even is set to true, the edges are split evenly so that each process gets almost the same number of edges.

When force_even is True, the data locality is still preserved if a graph is partitioned with Metis and the node/edge IDs are shuffled. In this case, majority of the nodes returned for a process are the ones that belong to the process. If node/edge IDs are not shuffled, data locality is not guaranteed.

Parameters
  • edges (1D tensor or DistTensor) – A boolean mask vector that indicates input edges.

  • partition_book (GraphPartitionBook) – The graph partition book

  • rank (int) – The rank of a process. If not given, the rank of the current process is used.

  • force_even (bool) – Force the edges are split evenly.

Returns

The vector of edge Ids that belong to the rank.

Return type

1D-tensor