dmlc--dgl
Zihao Ye
af61e2fbb4
* init gat * fix * gin * 7 nn modules * rename & lint * upd * upd * fix lint * upd test * upd * lint * shape check * upd * lint * address comments * update tensorflow Co-authored-by: Quan Gan <coin2028@hotmail.com> Co-authored-by: Jinjing Zhou <VoVAllen@users.noreply.github.com> Co-authored-by: Minjie Wang <wmjlyjemaine@gmail.com>
83 行
3.1 KiB
Python
83 行
3.1 KiB
Python
"""Torch Module for Graph Isomorphism Network layer"""
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# pylint: disable= no-member, arguments-differ, invalid-name
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import torch as th
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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 GINConv(nn.Module):
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r"""Graph Isomorphism Network layer from paper `How Powerful are Graph
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Neural Networks? <https://arxiv.org/pdf/1810.00826.pdf>`__.
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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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\mathrm{aggregate}\left(\left\{h_j^{l}, j\in\mathcal{N}(i)
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\right\}\right)\right)
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Parameters
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----------
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apply_func : callable activation function/layer or None
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If not None, apply this function to the updated node feature,
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the :math:`f_\Theta` in the formula.
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aggregator_type : str
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Aggregator type to use (``sum``, ``max`` or ``mean``).
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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.
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"""
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def __init__(self,
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apply_func,
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aggregator_type,
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init_eps=0,
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learn_eps=False):
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super(GINConv, self).__init__()
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self.apply_func = apply_func
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if aggregator_type == 'sum':
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self._reducer = fn.sum
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elif aggregator_type == 'max':
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self._reducer = fn.max
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elif aggregator_type == 'mean':
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self._reducer = fn.mean
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else:
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raise KeyError('Aggregator type {} not recognized.'.format(aggregator_type))
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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 = th.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 forward(self, graph, feat):
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r"""Compute Graph Isomorphism Network layer.
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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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feat : torch.Tensor or pair of torch.Tensor
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If a torch.Tensor is given, 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 dimensionality requirement of ``apply_func``.
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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 dimensionality of ``apply_func``.
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If ``apply_func`` is None, :math:`D_{out}` should be the same
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as input dimensionality.
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"""
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graph = graph.local_var()
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feat_src, feat_dst = expand_as_pair(feat)
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graph.srcdata['h'] = feat_src
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graph.update_all(fn.copy_u('h', 'm'), self._reducer('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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