Files
dgl/examples/tensorflow/gat/train.py

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"""
Graph Attention Networks in DGL using SPMV optimization.
Multiple heads are also batched together for faster training.
Compared with the original paper, this code does not implement
early stopping.
References
----------
Paper: https://arxiv.org/abs/1710.10903
Author's code: https://github.com/PetarV-/GAT
Pytorch implementation: https://github.com/Diego999/pyGAT
"""
import argparse
import time
import dgl
import networkx as nx
import numpy as np
import tensorflow as tf
from dgl.data import (
CiteseerGraphDataset,
CoraGraphDataset,
PubmedGraphDataset,
register_data_args,
)
from gat import GAT
from utils import EarlyStopping
def accuracy(logits, labels):
indices = tf.math.argmax(logits, axis=1)
acc = tf.reduce_mean(tf.cast(indices == labels, dtype=tf.float32))
return acc.numpy().item()
def evaluate(model, features, labels, mask):
logits = model(features, training=False)
logits = logits[mask]
labels = labels[mask]
return accuracy(logits, labels)
def main(args):
# load and preprocess dataset
if args.dataset == "cora":
data = CoraGraphDataset()
elif args.dataset == "citeseer":
data = CiteseerGraphDataset()
elif args.dataset == "pubmed":
data = PubmedGraphDataset()
else:
raise ValueError("Unknown dataset: {}".format(args.dataset))
g = data[0]
if args.gpu < 0:
device = "/cpu:0"
else:
device = "/gpu:{}".format(args.gpu)
g = g.to(device)
with tf.device(device):
features = g.ndata["feat"]
labels = g.ndata["label"]
train_mask = g.ndata["train_mask"]
val_mask = g.ndata["val_mask"]
test_mask = g.ndata["test_mask"]
num_feats = features.shape[1]
n_classes = data.num_classes
n_edges = g.number_of_edges()
print(
"""----Data statistics------'
#Edges %d
#Classes %d
#Train samples %d
#Val samples %d
#Test samples %d"""
% (
n_edges,
n_classes,
train_mask.numpy().sum(),
val_mask.numpy().sum(),
test_mask.numpy().sum(),
)
)
g = dgl.remove_self_loop(g)
g = dgl.add_self_loop(g)
n_edges = g.number_of_edges()
# create model
heads = ([args.num_heads] * args.num_layers) + [args.num_out_heads]
model = GAT(
g,
args.num_layers,
num_feats,
args.num_hidden,
n_classes,
heads,
tf.nn.elu,
args.in_drop,
args.attn_drop,
args.negative_slope,
args.residual,
)
print(model)
if args.early_stop:
stopper = EarlyStopping(patience=100)
# loss_fcn = tf.keras.losses.SparseCategoricalCrossentropy(
# from_logits=False)
loss_fcn = tf.nn.sparse_softmax_cross_entropy_with_logits
# use optimizer
optimizer = tf.keras.optimizers.Adam(
learning_rate=args.lr, epsilon=1e-8
)
# initialize graph
dur = []
for epoch in range(args.epochs):
if epoch >= 3:
t0 = time.time()
# forward
with tf.GradientTape() as tape:
tape.watch(model.trainable_weights)
logits = model(features, training=True)
loss_value = tf.reduce_mean(
loss_fcn(
labels=labels[train_mask], logits=logits[train_mask]
)
)
# Manually Weight Decay
# We found Tensorflow has a different implementation on weight decay
# of Adam(W) optimizer with PyTorch. And this results in worse results.
# Manually adding weights to the loss to do weight decay solves this problem.
for weight in model.trainable_weights:
loss_value = loss_value + args.weight_decay * tf.nn.l2_loss(
weight
)
grads = tape.gradient(loss_value, model.trainable_weights)
optimizer.apply_gradients(zip(grads, model.trainable_weights))
if epoch >= 3:
dur.append(time.time() - t0)
train_acc = accuracy(logits[train_mask], labels[train_mask])
if args.fastmode:
val_acc = accuracy(logits[val_mask], labels[val_mask])
else:
val_acc = evaluate(model, features, labels, val_mask)
if args.early_stop:
if stopper.step(val_acc, model):
break
print(
"Epoch {:05d} | Time(s) {:.4f} | Loss {:.4f} | TrainAcc {:.4f} |"
" ValAcc {:.4f} | ETputs(KTEPS) {:.2f}".format(
epoch,
np.mean(dur),
loss_value.numpy().item(),
train_acc,
val_acc,
n_edges / np.mean(dur) / 1000,
)
)
print()
if args.early_stop:
model.load_weights("es_checkpoint.pb")
acc = evaluate(model, features, labels, test_mask)
print("Test Accuracy {:.4f}".format(acc))
if __name__ == "__main__":
parser = argparse.ArgumentParser(description="GAT")
register_data_args(parser)
parser.add_argument(
"--gpu",
type=int,
default=-1,
help="which GPU to use. Set -1 to use CPU.",
)
parser.add_argument(
"--epochs", type=int, default=200, help="number of training epochs"
)
parser.add_argument(
"--num-heads",
type=int,
default=8,
help="number of hidden attention heads",
)
parser.add_argument(
"--num-out-heads",
type=int,
default=1,
help="number of output attention heads",
)
parser.add_argument(
"--num-layers", type=int, default=1, help="number of hidden layers"
)
parser.add_argument(
"--num-hidden", type=int, default=8, help="number of hidden units"
)
parser.add_argument(
"--residual",
action="store_true",
default=False,
help="use residual connection",
)
parser.add_argument(
"--in-drop", type=float, default=0.6, help="input feature dropout"
)
parser.add_argument(
"--attn-drop", type=float, default=0.6, help="attention dropout"
)
parser.add_argument("--lr", type=float, default=0.005, help="learning rate")
parser.add_argument(
"--weight-decay", type=float, default=5e-4, help="weight decay"
)
parser.add_argument(
"--negative-slope",
type=float,
default=0.2,
help="the negative slope of leaky relu",
)
parser.add_argument(
"--early-stop",
action="store_true",
default=False,
help="indicates whether to use early stop or not",
)
parser.add_argument(
"--fastmode",
action="store_true",
default=False,
help="skip re-evaluate the validation set",
)
args = parser.parse_args()
print(args)
main(args)