from typing import Callable, Tuple, Union
import torch
from torch import Tensor
from torch.nn import Parameter
from torch_geometric.nn.conv import MessagePassing
from torch_geometric.nn.dense.linear import Linear
from torch_geometric.nn.inits import reset, zeros
from torch_geometric.typing import Adj, OptPairTensor, OptTensor, Size
[docs]class NNConv(MessagePassing):
r"""The continuous kernel-based convolutional operator from the
`"Neural Message Passing for Quantum Chemistry"
<https://arxiv.org/abs/1704.01212>`_ paper.
This convolution is also known as the edge-conditioned convolution from the
`"Dynamic Edge-Conditioned Filters in Convolutional Neural Networks on
Graphs" <https://arxiv.org/abs/1704.02901>`_ paper (see
:class:`torch_geometric.nn.conv.ECConv` for an alias):
.. math::
\mathbf{x}^{\prime}_i = \mathbf{\Theta} \mathbf{x}_i +
\sum_{j \in \mathcal{N}(i)} \mathbf{x}_j \cdot
h_{\mathbf{\Theta}}(\mathbf{e}_{i,j}),
where :math:`h_{\mathbf{\Theta}}` denotes a neural network, *.i.e.*
a MLP.
Args:
in_channels (int or tuple): Size of each input sample, or :obj:`-1` to
derive the size from the first input(s) to the forward method.
A tuple corresponds to the sizes of source and target
dimensionalities.
out_channels (int): Size of each output sample.
nn (torch.nn.Module): A neural network :math:`h_{\mathbf{\Theta}}` that
maps edge features :obj:`edge_attr` of shape :obj:`[-1,
num_edge_features]` to shape
:obj:`[-1, in_channels * out_channels]`, *e.g.*, defined by
:class:`torch.nn.Sequential`.
aggr (string, optional): The aggregation scheme to use
(:obj:`"add"`, :obj:`"mean"`, :obj:`"max"`).
(default: :obj:`"add"`)
root_weight (bool, optional): If set to :obj:`False`, the layer will
not add the transformed root node features to the output.
(default: :obj:`True`)
bias (bool, optional): If set to :obj:`False`, the layer will not learn
an additive bias. (default: :obj:`True`)
**kwargs (optional): Additional arguments of
:class:`torch_geometric.nn.conv.MessagePassing`.
Shapes:
- **input:**
node features :math:`(|\mathcal{V}|, F_{in})` or
:math:`((|\mathcal{V_s}|, F_{s}), (|\mathcal{V_t}|, F_{t}))`
if bipartite,
edge indices :math:`(2, |\mathcal{E}|)`,
edge features :math:`(|\mathcal{E}|, D)` *(optional)*
- **output:** node features :math:`(|\mathcal{V}|, F_{out})` or
:math:`(|\mathcal{V}_t|, F_{out})` if bipartite
"""
def __init__(self, in_channels: Union[int, Tuple[int, int]],
out_channels: int, nn: Callable, aggr: str = 'add',
root_weight: bool = True, bias: bool = True, **kwargs):
super().__init__(aggr=aggr, **kwargs)
self.in_channels = in_channels
self.out_channels = out_channels
self.nn = nn
self.root_weight = root_weight
if isinstance(in_channels, int):
in_channels = (in_channels, in_channels)
self.in_channels_l = in_channels[0]
if root_weight:
self.lin = Linear(in_channels[1], out_channels, bias=False,
weight_initializer='uniform')
if bias:
self.bias = Parameter(torch.Tensor(out_channels))
else:
self.register_parameter('bias', None)
self.reset_parameters()
[docs] def reset_parameters(self):
reset(self.nn)
if self.root_weight:
self.lin.reset_parameters()
zeros(self.bias)
[docs] def forward(self, x: Union[Tensor, OptPairTensor], edge_index: Adj,
edge_attr: OptTensor = None, size: Size = None) -> Tensor:
""""""
if isinstance(x, Tensor):
x: OptPairTensor = (x, x)
# propagate_type: (x: OptPairTensor, edge_attr: OptTensor)
out = self.propagate(edge_index, x=x, edge_attr=edge_attr, size=size)
x_r = x[1]
if x_r is not None and self.root_weight:
out += self.lin(x_r)
if self.bias is not None:
out += self.bias
return out
def message(self, x_j: Tensor, edge_attr: Tensor) -> Tensor:
weight = self.nn(edge_attr)
weight = weight.view(-1, self.in_channels_l, self.out_channels)
return torch.matmul(x_j.unsqueeze(1), weight).squeeze(1)
def __repr__(self) -> str:
return (f'{self.__class__.__name__}({self.in_channels}, '
f'{self.out_channels}, aggr={self.aggr}, nn={self.nn})')
ECConv = NNConv