dgl.udf.EdgeBatch.src¶
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property
EdgeBatch.
src
¶ Return a view of the source node features for the edges in the batch.
Examples
The following example uses PyTorch backend.
>>> import dgl >>> import torch
>>> # Instantiate a graph and set a node feature 'h' >>> g = dgl.graph((torch.tensor([0, 1, 1]), torch.tensor([1, 1, 0]))) >>> g.ndata['h'] = torch.ones(2, 1)
>>> # Define a UDF that retrieves the source node features for edges >>> def edge_udf(edges): >>> # edges.src['h'] is a tensor of shape (E, 1), >>> # where E is the number of edges in the batch. >>> return {'src': edges.src['h']}
>>> # Copy features from source nodes to edges >>> g.apply_edges(edge_udf) >>> g.edata['src'] tensor([[1.], [1.], [1.]])
>>> # Use edge UDF in message passing, which is equivalent to dgl.function.copy_u >>> import dgl.function as fn >>> g.update_all(edge_udf, fn.sum('src', 'h')) >>> g.ndata['h'] tensor([[1.], [2.]])