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

192 lines
6.2 KiB
Python

import dgl
import dgl.function as fn
import dgl.nn as dglnn
import torch
import torch.nn as nn
import torch.nn.functional as F
import torchmetrics.functional as MF
import tqdm
from dgl import apply_each
from dgl.dataloading import DataLoader, NeighborSampler
from ogb.nodeproppred import DglNodePropPredDataset
class HeteroGAT(nn.Module):
def __init__(self, etypes, in_size, hid_size, out_size, n_heads=4):
super().__init__()
self.layers = nn.ModuleList()
self.layers.append(
dglnn.HeteroGraphConv(
{
etype: dglnn.GATConv(in_size, hid_size // n_heads, n_heads)
for etype in etypes
}
)
)
self.layers.append(
dglnn.HeteroGraphConv(
{
etype: dglnn.GATConv(hid_size, hid_size // n_heads, n_heads)
for etype in etypes
}
)
)
self.layers.append(
dglnn.HeteroGraphConv(
{
etype: dglnn.GATConv(hid_size, hid_size // n_heads, n_heads)
for etype in etypes
}
)
)
self.dropout = nn.Dropout(0.5)
self.linear = nn.Linear(hid_size, out_size) # Should be HeteroLinear
def forward(self, blocks, x):
h = x
for l, (layer, block) in enumerate(zip(self.layers, blocks)):
h = layer(block, h)
# One thing is that h might return tensors with zero rows if the number of dst nodes
# of one node type is 0. x.view(x.shape[0], -1) wouldn't work in this case.
h = apply_each(
h, lambda x: x.view(x.shape[0], x.shape[1] * x.shape[2])
)
if l != len(self.layers) - 1:
h = apply_each(h, F.relu)
h = apply_each(h, self.dropout)
return self.linear(h["paper"])
def evaluate(num_classes, model, dataloader, desc):
preds = []
labels = []
with torch.no_grad():
for input_nodes, output_nodes, blocks in tqdm.tqdm(
dataloader, desc=desc
):
x = blocks[0].srcdata["feat"]
y = blocks[-1].dstdata["label"]["paper"][:, 0]
y_hat = model(blocks, x)
preds.append(y_hat.cpu())
labels.append(y.cpu())
preds = torch.cat(preds, 0)
labels = torch.cat(labels, 0)
acc = MF.accuracy(
preds, labels, task="multiclass", num_classes=num_classes
)
return acc
def train(train_loader, val_loader, test_loader, num_classes, model):
# loss function and optimizer
loss_fcn = nn.CrossEntropyLoss()
opt = torch.optim.Adam(model.parameters(), lr=0.001, weight_decay=5e-4)
# training loop
for epoch in range(10):
model.train()
total_loss = 0
for it, (input_nodes, output_nodes, blocks) in enumerate(
tqdm.tqdm(train_dataloader, desc="Train")
):
x = blocks[0].srcdata["feat"]
y = blocks[-1].dstdata["label"]["paper"][:, 0]
y_hat = model(blocks, x)
loss = loss_fcn(y_hat, y)
opt.zero_grad()
loss.backward()
opt.step()
total_loss += loss.item()
model.eval()
val_acc = evaluate(num_classes, model, val_dataloader, "Val. ")
test_acc = evaluate(num_classes, model, test_dataloader, "Test ")
print(
f"Epoch {epoch:05d} | Loss {total_loss/(it+1):.4f} | Validation Acc. {val_acc.item():.4f} | Test Acc. {test_acc.item():.4f}"
)
if __name__ == "__main__":
print(
f"Training with DGL built-in HeteroGraphConv using GATConv as its convolution sub-modules"
)
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
# load and preprocess dataset
print("Loading data")
dataset = DglNodePropPredDataset("ogbn-mag")
graph, labels = dataset[0]
graph.ndata["label"] = labels
# add reverse edges in "cites" relation, and add reverse edge types for the rest etypes
graph = dgl.AddReverse()(graph)
# precompute the author, topic, and institution features
graph.update_all(
fn.copy_u("feat", "m"), fn.mean("m", "feat"), etype="rev_writes"
)
graph.update_all(
fn.copy_u("feat", "m"), fn.mean("m", "feat"), etype="has_topic"
)
graph.update_all(
fn.copy_u("feat", "m"), fn.mean("m", "feat"), etype="affiliated_with"
)
# find train/val/test indexes
split_idx = dataset.get_idx_split()
train_idx, val_idx, test_idx = (
split_idx["train"],
split_idx["valid"],
split_idx["test"],
)
train_idx = apply_each(train_idx, lambda x: x.to(device))
val_idx = apply_each(val_idx, lambda x: x.to(device))
test_idx = apply_each(test_idx, lambda x: x.to(device))
# create RGAT model
in_size = graph.ndata["feat"]["paper"].shape[1]
num_classes = dataset.num_classes
model = HeteroGAT(graph.etypes, in_size, 256, num_classes).to(device)
# dataloader + model training + testing
train_sampler = NeighborSampler(
[5, 5, 5],
prefetch_node_feats={k: ["feat"] for k in graph.ntypes},
prefetch_labels={"paper": ["label"]},
)
val_sampler = NeighborSampler(
[10, 10, 10],
prefetch_node_feats={k: ["feat"] for k in graph.ntypes},
prefetch_labels={"paper": ["label"]},
)
train_dataloader = DataLoader(
graph,
train_idx,
train_sampler,
device=device,
batch_size=1000,
shuffle=True,
drop_last=False,
num_workers=0,
use_uva=torch.cuda.is_available(),
)
val_dataloader = DataLoader(
graph,
val_idx,
val_sampler,
device=device,
batch_size=1000,
shuffle=False,
drop_last=False,
num_workers=0,
use_uva=torch.cuda.is_available(),
)
test_dataloader = DataLoader(
graph,
test_idx,
val_sampler,
device=device,
batch_size=1000,
shuffle=False,
drop_last=False,
num_workers=0,
use_uva=torch.cuda.is_available(),
)
train(train_dataloader, val_dataloader, test_dataloader, num_classes, model)