Source code for cogdl.models.nn.gtn

import math

import torch
import torch.nn as nn
import torch.nn.functional as F

from torch_sparse import spspmm

from .. import BaseModel
from cogdl.layers import GCNLayer
from cogdl.utils import remove_self_loops, coalesce

class GTConv(nn.Module):
    def __init__(self, in_channels, out_channels, num_nodes):
        super(GTConv, self).__init__()
        self.in_channels = in_channels
        self.out_channels = out_channels
        self.weight = nn.Parameter(torch.Tensor(out_channels, in_channels))
        self.bias = None
        self.scale = nn.Parameter(torch.Tensor([0.1]), requires_grad=False)
        self.num_nodes = num_nodes

    def reset_parameters(self):
        nn.init.constant_(self.weight, 1)
        if self.bias is not None:
            fan_in, _ = nn.init._calculate_fan_in_and_fan_out(self.weight)
            bound = 1 / math.sqrt(fan_in)
            nn.init.uniform_(self.bias, -bound, bound)

    def forward(self, A):
        filter = F.softmax(self.weight, dim=1)
        num_channels = filter.shape[0]
        results = []
        for i in range(num_channels):
            for j, (edge_index, edge_value) in enumerate(A):
                if j == 0:
                    total_edge_index = edge_index
                    total_edge_value = edge_value * filter[i][j]
                    total_edge_index =, edge_index), dim=1)
                    total_edge_value =, edge_value * filter[i][j]))
            row, col = total_edge_index.detach()
            row, col, value = coalesce(row, col, total_edge_value)
            index = torch.stack([row, col])
            results.append((index, value))
        return results

class GTLayer(nn.Module):
    def __init__(self, in_channels, out_channels, num_nodes, first=True):
        super(GTLayer, self).__init__()
        self.in_channels = in_channels
        self.out_channels = out_channels
        self.first = first
        self.num_nodes = num_nodes
        if self.first:
            self.conv1 = GTConv(in_channels, out_channels, num_nodes)
            self.conv2 = GTConv(in_channels, out_channels, num_nodes)
            self.conv1 = GTConv(in_channels, out_channels, num_nodes)

    def forward(self, A, H_=None):
        if self.first:
            result_A = self.conv1(A)
            result_B = self.conv2(A)
            W = [(F.softmax(self.conv1.weight, dim=1)).detach(), (F.softmax(self.conv2.weight, dim=1)).detach()]
            result_A = H_
            result_B = self.conv1(A)
            W = [(F.softmax(self.conv1.weight, dim=1)).detach()]
        H = []
        device = result_A[0][0].device
        for i in range(len(result_A)):
            # a_edge, a_value = result_A[i][0].cpu(), result_A[i][1].cpu()
            # b_edge, b_value = result_B[i][0].cpu(), result_B[i][1].cpu()

            a_edge, a_value = result_A[i][0], result_A[i][1]
            b_edge, b_value = result_B[i][0], result_B[i][1]

            edges, values = spspmm(a_edge, a_value, b_edge, b_value, self.num_nodes, self.num_nodes, self.num_nodes)
        return H, W

[docs]class GTN(BaseModel):
[docs] @staticmethod def add_args(parser): """Add model-specific arguments to the parser.""" # fmt: off parser.add_argument("--num-features", type=int) parser.add_argument("--num-classes", type=int) parser.add_argument("--num-nodes", type=int) parser.add_argument("--hidden-size", type=int, default=64) parser.add_argument("--num-layers", type=int, default=2) parser.add_argument("--num-edge", type=int, default=2) parser.add_argument("--num-channels", type=int, default=2)
# fmt: on
[docs] @classmethod def build_model_from_args(cls, args): return cls( args.num_edge, args.num_channels, args.num_features, args.hidden_size, args.num_classes, args.num_nodes, args.num_layers, )
def __init__(self, num_edge, num_channels, w_in, w_out, num_class, num_nodes, num_layers): super(GTN, self).__init__() self.num_edge = num_edge self.num_channels = num_channels self.num_nodes = num_nodes self.w_in = w_in self.w_out = w_out self.num_class = num_class self.num_layers = num_layers layers = [] for i in range(num_layers): if i == 0: layers.append(GTLayer(num_edge, num_channels, num_nodes, first=True)) else: layers.append(GTLayer(num_edge, num_channels, num_nodes, first=False)) self.layers = nn.ModuleList(layers) self.cross_entropy_loss = nn.CrossEntropyLoss() self.gcn = GCNLayer(in_features=self.w_in, out_features=w_out) self.linear1 = nn.Linear(self.w_out * self.num_channels, self.w_out) self.linear2 = nn.Linear(self.w_out, self.num_class)
[docs] def normalization(self, H): norm_H = [] for i in range(self.num_channels): edge, value = H[i] edge, value = remove_self_loops(edge, value) edge = torch.stack(edge) deg_row, deg_col = self.norm(edge.detach(), self.num_nodes, value.detach()) value = deg_col * value norm_H.append((edge, value)) return norm_H
[docs] def norm(self, edge_index, num_nodes, edge_weight, improved=False, dtype=None): with torch.no_grad(): if edge_weight is None: edge_weight = torch.ones((edge_index.size(1),), dtype=dtype, device=edge_index.device) edge_weight = edge_weight.view(-1) assert edge_weight.size(0) == edge_index.size(1) row, col = edge_index deg = torch.zeros((num_nodes,)).to(edge_index.device) deg = deg.scatter_add_(dim=0, src=edge_weight, index=row).squeeze() deg_inv_sqrt = deg.pow(-1) deg_inv_sqrt[deg_inv_sqrt == float("inf")] = 0 return deg_inv_sqrt[row], deg_inv_sqrt[col]
[docs] def forward(self, graph): A = graph.adj X = graph.x Ws = [] for i in range(self.num_layers): if i == 0: H, W = self.layers[i](A) else: H = self.normalization(H) H, W = self.layers[i](A, H) Ws.append(W) with graph.local_graph(): for i in range(self.num_channels): if i == 0: edge_index, edge_weight = H[i][0], H[i][1] graph.edge_index = edge_index.detach() graph.edge_weight = edge_weight X_ = self.gcn(graph, X) X_ = F.relu(X_) else: edge_index, edge_weight = H[i][0], H[i][1] graph.edge_index = edge_index.detach() graph.edge_weight = edge_weight X_ =, F.relu(self.gcn(graph, X))), dim=1) X_ = self.linear1(X_) X_ = F.relu(X_) out = self.linear2(X_) return out