98 lines
3.6 KiB
Python
98 lines
3.6 KiB
Python
"""Torch Module for Graph Isomorphism Network layer variant with edge features"""
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# pylint: disable= no-member, arguments-differ, invalid-name
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import torch as th
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import torch.nn.functional as F
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from torch import nn
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from .... import function as fn
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from ....utils import expand_as_pair
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class GINEConv(nn.Module):
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r"""Graph Isomorphism Network with Edge Features, introduced by
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`Strategies for Pre-training Graph Neural Networks <https://arxiv.org/abs/1905.12265>`__
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.. math::
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h_i^{(l+1)} = f_\Theta \left((1 + \epsilon) h_i^{l} +
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\sum_{j\in\mathcal{N}(i)}\mathrm{ReLU}(h_j^{l} + e_{j,i}^{l})\right)
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where :math:`e_{j,i}^{l}` is the edge feature.
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Parameters
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----------
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apply_func : callable module or None
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The :math:`f_\Theta` in the formula. If not None, it will be applied to
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the updated node features. The default value is None.
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init_eps : float, optional
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Initial :math:`\epsilon` value, default: ``0``.
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learn_eps : bool, optional
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If True, :math:`\epsilon` will be a learnable parameter. Default: ``False``.
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Examples
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--------
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>>> import dgl
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>>> import torch
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>>> import torch.nn as nn
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>>> from dgl.nn import GINEConv
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>>> g = dgl.graph(([0, 1, 2], [1, 1, 3]))
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>>> in_feats = 10
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>>> out_feats = 20
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>>> nfeat = torch.randn(g.num_nodes(), in_feats)
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>>> efeat = torch.randn(g.num_edges(), in_feats)
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>>> conv = GINEConv(nn.Linear(in_feats, out_feats))
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>>> res = conv(g, nfeat, efeat)
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>>> print(res.shape)
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torch.Size([4, 20])
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"""
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def __init__(self, apply_func=None, init_eps=0, learn_eps=False):
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super(GINEConv, self).__init__()
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self.apply_func = apply_func
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# to specify whether eps is trainable or not.
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if learn_eps:
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self.eps = nn.Parameter(th.FloatTensor([init_eps]))
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else:
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self.register_buffer("eps", th.FloatTensor([init_eps]))
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def message(self, edges):
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r"""User-defined Message Function"""
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return {"m": F.relu(edges.src["hn"] + edges.data["he"])}
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def forward(self, graph, node_feat, edge_feat):
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r"""Forward computation.
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Parameters
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----------
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graph : DGLGraph
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The graph.
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node_feat : torch.Tensor or pair of torch.Tensor
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If a torch.Tensor is given, it is the input feature of shape :math:`(N, D_{in})` where
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:math:`D_{in}` is size of input feature, :math:`N` is the number of nodes.
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If a pair of torch.Tensor is given, the pair must contain two tensors of shape
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:math:`(N_{in}, D_{in})` and :math:`(N_{out}, D_{in})`.
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If ``apply_func`` is not None, :math:`D_{in}` should
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fit the input feature size requirement of ``apply_func``.
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edge_feat : torch.Tensor
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Edge feature. It is a tensor of shape :math:`(E, D_{in})` where :math:`E`
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is the number of edges.
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Returns
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-------
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torch.Tensor
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The output feature of shape :math:`(N, D_{out})` where
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:math:`D_{out}` is the output feature size of ``apply_func``.
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If ``apply_func`` is None, :math:`D_{out}` should be the same
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as :math:`D_{in}`.
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"""
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with graph.local_scope():
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feat_src, feat_dst = expand_as_pair(node_feat, graph)
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graph.srcdata["hn"] = feat_src
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graph.edata["he"] = edge_feat
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graph.update_all(self.message, fn.sum("m", "neigh"))
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rst = (1 + self.eps) * feat_dst + graph.dstdata["neigh"]
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if self.apply_func is not None:
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rst = self.apply_func(rst)
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return rst
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