Source code for dgl.nn.pytorch.conv.cfconv

"""Torch modules for interaction blocks in SchNet"""
# pylint: disable= no-member, arguments-differ, invalid-name
import numpy as np
import torch.nn as nn

from .... import function as fn

class ShiftedSoftplus(nn.Module):
    r"""Applies the element-wise function:

    .. math::
        \text{SSP}(x) = \frac{1}{\beta} * \log(1 + \exp(\beta * x)) - \log(\text{shift})

    beta : int
        :math:`\beta` value for the mathematical formulation. Default to 1.
    shift : int
        :math:`\text{shift}` value for the mathematical formulation. Default to 2.
    def __init__(self, beta=1, shift=2, threshold=20):
        super(ShiftedSoftplus, self).__init__()

        self.shift = shift
        self.softplus = nn.Softplus(beta=beta, threshold=threshold)

    def forward(self, inputs):

        Applies the activation function.

        inputs : float32 tensor of shape (N, *)
            * denotes any number of additional dimensions.

        float32 tensor of shape (N, *)
            Result of applying the activation function to the input.
        return self.softplus(inputs) - np.log(float(self.shift))

[docs]class CFConv(nn.Module): r"""CFConv from `SchNet: A continuous-filter convolutional neural network for modeling quantum interactions <>`__ It combines node and edge features in message passing and updates node representations. .. math:: h_i^{(l+1)} = \sum_{j\in \mathcal{N}(i)} h_j^{l} \circ W^{(l)}e_ij where :math:`\circ` represents element-wise multiplication and for :math:`\text{SPP}` : .. math:: \text{SSP}(x) = \frac{1}{\beta} * \log(1 + \exp(\beta * x)) - \log(\text{shift}) Parameters ---------- node_in_feats : int Size for the input node features :math:`h_j^{(l)}`. edge_in_feats : int Size for the input edge features :math:`e_ij`. hidden_feats : int Size for the hidden representations. out_feats : int Size for the output representations :math:`h_j^{(l+1)}`. Example ------- >>> import dgl >>> import numpy as np >>> import torch as th >>> from dgl.nn import CFConv >>> g = dgl.graph(([0,1,2,3,2,5], [1,2,3,4,0,3])) >>> nfeat = th.ones(6, 10) >>> efeat = th.ones(6, 5) >>> conv = CFConv(10, 5, 3, 2) >>> res = conv(g, nfeat, efeat) >>> res tensor([[-0.1209, -0.2289], [-0.1209, -0.2289], [-0.1209, -0.2289], [-0.1135, -0.2338], [-0.1209, -0.2289], [-0.1283, -0.2240]], grad_fn=<SubBackward0>) """ def __init__(self, node_in_feats, edge_in_feats, hidden_feats, out_feats): super(CFConv, self).__init__() self.project_edge = nn.Sequential( nn.Linear(edge_in_feats, hidden_feats), ShiftedSoftplus(), nn.Linear(hidden_feats, hidden_feats), ShiftedSoftplus() ) self.project_node = nn.Linear(node_in_feats, hidden_feats) self.project_out = nn.Sequential( nn.Linear(hidden_feats, out_feats), ShiftedSoftplus() )
[docs] def forward(self, g, node_feats, edge_feats): """ Description ----------- Performs message passing and updates node representations. Parameters ---------- g : DGLGraph The graph. node_feats : torch.Tensor or pair of torch.Tensor The input node features. If a torch.Tensor is given, it represents the input node feature of shape :math:`(N, D_{in})` where :math:`D_{in}` is size of input feature, :math:`N` is the number of nodes. If a pair of torch.Tensor is given, which is the case for bipartite graph, the pair must contain two tensors of shape :math:`(N_{src}, D_{in_{src}})` and :math:`(N_{dst}, D_{in_{dst}})` separately for the source and destination nodes. edge_feats : torch.Tensor The input edge feature of shape :math:`(E, edge_in_feats)` where :math:`E` is the number of edges. Returns ------- torch.Tensor The output node feature of shape :math:`(N_{out}, out_feats)` where :math:`N_{out}` is the number of destination nodes. """ with g.local_scope(): if isinstance(node_feats, tuple): node_feats_src, _ = node_feats else: node_feats_src = node_feats g.srcdata['hv'] = self.project_node(node_feats_src) g.edata['he'] = self.project_edge(edge_feats) g.update_all(fn.u_mul_e('hv', 'he', 'm'), fn.sum('m', 'h')) return self.project_out(g.dstdata['h'])