What is the block?

fanaev · May 9, 2022, 12:38am

Hello, may anyone explain what the block is? I have met them in example/pinsage and I can’t understand how does they work

Rhett-Ying · May 9, 2022, 2:41am

A block is a graph consisting of two sets of nodes: the source nodes and destination nodes. The source and destination nodes can have multiple node types. All the edges connect from source nodes to destination nodes.

Please refer to below links for more details:
https://docs.dgl.ai/generated/dgl.to_block.html#dgl-to-block
https://docs.dgl.ai/generated/dgl.create_block.html#dgl.create_block

github.com

dmlc/dgl/blob/34981bd676bc3429ab2ad4c26a27e7e76ee3e0b3/python/dgl/heterograph.py#L6371

      
        
                Returns
                -------
                str
                """
                if ids is None:
                    return '+'.join(sorted(names))
                else:
                    selected = sorted([names[i] for i in ids])
                    return '+'.join(selected)
            
            
class DGLBlock(DGLHeteroGraph):
                """Subclass that signifies the graph is a block created from
                :func:`dgl.to_block`.
                """
                # (BarclayII) I'm making a subclass because I don't want to make another version of
                # serialization that contains the is_block flag.
                is_block = True
            
            
    def __repr__(self):
                    if len(self.srctypes) == 1 and len(self.dsttypes) == 1 and len(self.etypes) == 1:
                        ret = 'Block(num_src_nodes={srcnode}, num_dst_nodes={dstnode}, num_edges={edge})'

minjie · May 9, 2022, 6:09am

Also check out this tutorial: Introduction of Neighbor Sampling for GNN Training — DGL 0.8.1 documentation . There is an animation to illustrate what is a DGLBlock (also called message flow graph). Hope this will help!

system · June 8, 2022, 6:10am

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