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2026-07-13 13:35:51 +08:00

188 lines
6.4 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import dgl
import dgl.function as fn
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
from .focal_loss import FocalLoss
from .graphconv import GraphConv
class LANDER(nn.Module):
def __init__(
self,
feature_dim,
nhid,
num_conv=4,
dropout=0,
use_GAT=True,
K=1,
balance=False,
use_cluster_feat=True,
use_focal_loss=True,
**kwargs
):
super(LANDER, self).__init__()
nhid_half = int(nhid / 2)
self.use_cluster_feat = use_cluster_feat
self.use_focal_loss = use_focal_loss
if self.use_cluster_feat:
self.feature_dim = feature_dim * 2
else:
self.feature_dim = feature_dim
input_dim = (feature_dim, nhid, nhid, nhid_half)
output_dim = (nhid, nhid, nhid_half, nhid_half)
self.conv = nn.ModuleList()
self.conv.append(GraphConv(self.feature_dim, nhid, dropout, use_GAT, K))
for i in range(1, num_conv):
self.conv.append(
GraphConv(input_dim[i], output_dim[i], dropout, use_GAT, K)
)
self.src_mlp = nn.Linear(output_dim[num_conv - 1], nhid_half)
self.dst_mlp = nn.Linear(output_dim[num_conv - 1], nhid_half)
self.classifier_conn = nn.Sequential(
nn.PReLU(nhid_half),
nn.Linear(nhid_half, nhid_half),
nn.PReLU(nhid_half),
nn.Linear(nhid_half, 2),
)
if self.use_focal_loss:
self.loss_conn = FocalLoss(2)
else:
self.loss_conn = nn.CrossEntropyLoss()
self.loss_den = nn.MSELoss()
self.balance = balance
def pred_conn(self, edges):
src_feat = self.src_mlp(edges.src["conv_features"])
dst_feat = self.dst_mlp(edges.dst["conv_features"])
pred_conn = self.classifier_conn(src_feat + dst_feat)
return {"pred_conn": pred_conn}
def pred_den_msg(self, edges):
prob = edges.data["prob_conn"]
res = edges.data["raw_affine"] * (prob[:, 1] - prob[:, 0])
return {"pred_den_msg": res}
def forward(self, bipartites):
if isinstance(bipartites, dgl.DGLGraph):
bipartites = [bipartites] * len(self.conv)
if self.use_cluster_feat:
neighbor_x = torch.cat(
[
bipartites[0].ndata["features"],
bipartites[0].ndata["cluster_features"],
],
axis=1,
)
else:
neighbor_x = bipartites[0].ndata["features"]
for i in range(len(self.conv)):
neighbor_x = self.conv[i](bipartites[i], neighbor_x)
output_bipartite = bipartites[-1]
output_bipartite.ndata["conv_features"] = neighbor_x
else:
if self.use_cluster_feat:
neighbor_x_src = torch.cat(
[
bipartites[0].srcdata["features"],
bipartites[0].srcdata["cluster_features"],
],
axis=1,
)
center_x_src = torch.cat(
[
bipartites[1].srcdata["features"],
bipartites[1].srcdata["cluster_features"],
],
axis=1,
)
else:
neighbor_x_src = bipartites[0].srcdata["features"]
center_x_src = bipartites[1].srcdata["features"]
for i in range(len(self.conv)):
neighbor_x_dst = neighbor_x_src[: bipartites[i].num_dst_nodes()]
neighbor_x_src = self.conv[i](
bipartites[i], (neighbor_x_src, neighbor_x_dst)
)
center_x_dst = center_x_src[: bipartites[i + 1].num_dst_nodes()]
center_x_src = self.conv[i](
bipartites[i + 1], (center_x_src, center_x_dst)
)
output_bipartite = bipartites[-1]
output_bipartite.srcdata["conv_features"] = neighbor_x_src
output_bipartite.dstdata["conv_features"] = center_x_src
output_bipartite.apply_edges(self.pred_conn)
output_bipartite.edata["prob_conn"] = F.softmax(
output_bipartite.edata["pred_conn"], dim=1
)
output_bipartite.update_all(
self.pred_den_msg, fn.mean("pred_den_msg", "pred_den")
)
return output_bipartite
def compute_loss(self, bipartite):
pred_den = bipartite.dstdata["pred_den"]
loss_den = self.loss_den(pred_den, bipartite.dstdata["density"])
labels_conn = bipartite.edata["labels_conn"]
mask_conn = bipartite.edata["mask_conn"]
if self.balance:
labels_conn = bipartite.edata["labels_conn"]
neg_check = torch.logical_and(
bipartite.edata["labels_conn"] == 0, mask_conn
)
num_neg = torch.sum(neg_check).item()
neg_indices = torch.where(neg_check)[0]
pos_check = torch.logical_and(
bipartite.edata["labels_conn"] == 1, mask_conn
)
num_pos = torch.sum(pos_check).item()
pos_indices = torch.where(pos_check)[0]
if num_pos > num_neg:
mask_conn[
pos_indices[
np.random.choice(
num_pos, num_pos - num_neg, replace=False
)
]
] = 0
elif num_pos < num_neg:
mask_conn[
neg_indices[
np.random.choice(
num_neg, num_neg - num_pos, replace=False
)
]
] = 0
# In subgraph training, it may happen that all edges are masked in a batch
if mask_conn.sum() > 0:
loss_conn = self.loss_conn(
bipartite.edata["pred_conn"][mask_conn], labels_conn[mask_conn]
)
loss = loss_den + loss_conn
loss_den_val = loss_den.item()
loss_conn_val = loss_conn.item()
else:
loss = loss_den
loss_den_val = loss_den.item()
loss_conn_val = 0
return loss, loss_den_val, loss_conn_val