Source code for torch_geometric.nn.conv.feast_conv

from typing import Union
from torch_geometric.typing import PairTensor, Adj

import torch
from torch import Tensor
from torch.nn import Parameter
import torch.nn.functional as F
from torch_sparse import SparseTensor, set_diag
from torch_geometric.nn.conv import MessagePassing
from torch_geometric.utils import remove_self_loops, add_self_loops

from ..inits import normal

[docs]class FeaStConv(MessagePassing): r"""The (translation-invariant) feature-steered convolutional operator from the `"FeaStNet: Feature-Steered Graph Convolutions for 3D Shape Analysis" <>`_ paper .. math:: \mathbf{x}^{\prime}_i = \frac{1}{|\mathcal{N}(i)|} \sum_{j \in \mathcal{N}(i)} \sum_{h=1}^H q_h(\mathbf{x}_i, \mathbf{x}_j) \mathbf{W}_h \mathbf{x}_j with :math:`q_h(\mathbf{x}_i, \mathbf{x}_j) = \mathrm{softmax}_j (\mathbf{u}_h^{\top} (\mathbf{x}_j - \mathbf{x}_i) + c_h)`, where :math:`H` denotes the number of attention heads, and :math:`\mathbf{W}_h`, :math:`\mathbf{u}_h` and :math:`c_h` are trainable parameters. Args: in_channels (int): Size of each input sample. out_channels (int): Size of each output sample. heads (int, optional): Number of attention heads :math:`H`. (default: :obj:`1`) add_self_loops (bool, optional): If set to :obj:`False`, will not add self-loops to the input graph. (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`. """ def __init__(self, in_channels: int, out_channels: int, heads: int = 1, add_self_loops: bool = True, bias: bool = True, **kwargs): super(FeaStConv, self).__init__(aggr='mean', **kwargs) self.in_channels = in_channels self.out_channels = out_channels self.heads = heads self.add_self_loops = add_self_loops self.weight = Parameter(torch.Tensor(in_channels, heads * out_channels)) self.u = Parameter(torch.Tensor(in_channels, heads)) self.c = Parameter(torch.Tensor(heads)) if bias: self.bias = Parameter(torch.Tensor(out_channels)) else: self.register_parameter('bias', None) self.reset_parameters()
[docs] def reset_parameters(self): normal(self.weight, mean=0, std=0.1) normal(self.u, mean=0, std=0.1) normal(self.c, mean=0, std=0.1) normal(self.bias, mean=0, std=0.1)
[docs] def forward(self, x: Union[Tensor, PairTensor], edge_index: Adj) -> Tensor: """""" if isinstance(x, Tensor): x: PairTensor = (x, x) if self.add_self_loops: if isinstance(edge_index, Tensor): edge_index, _ = remove_self_loops(edge_index) edge_index, _ = add_self_loops(edge_index, num_nodes=x[1].size(0)) elif isinstance(edge_index, SparseTensor): edge_index = set_diag(edge_index) # propagate_type: (x: PairTensor) out = self.propagate(edge_index, x=x, size=None) if self.bias is not None: out += self.bias return out
def message(self, x_i: Tensor, x_j: Tensor) -> Tensor: q = - x_i), self.u) + self.c # Translation invariance. q = F.softmax(q, dim=1) x_j =, self.weight).view(x_j.size(0), self.heads, -1) return (x_j * q.view(-1, self.heads, 1)).sum(dim=1) def __repr__(self): return '{}({}, {}, heads={})'.format(self.__class__.__name__, self.in_channels, self.out_channels, self.heads)