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

176 lines
5.3 KiB
Python

"""
Supervised Community Detection with Hierarchical Graph Neural Networks
https://arxiv.org/abs/1705.08415
Author's implementation: https://github.com/joanbruna/GNN_community
"""
from __future__ import division
import argparse
import time
from itertools import permutations
import gnn
import numpy as np
import torch as th
import torch.nn.functional as F
import torch.optim as optim
from dgl.data import SBMMixtureDataset
from torch.utils.data import DataLoader
parser = argparse.ArgumentParser()
parser.add_argument("--batch-size", type=int, help="Batch size", default=1)
parser.add_argument("--gpu", type=int, help="GPU index", default=-1)
parser.add_argument("--lr", type=float, help="Learning rate", default=0.001)
parser.add_argument(
"--n-communities", type=int, help="Number of communities", default=2
)
parser.add_argument(
"--n-epochs", type=int, help="Number of epochs", default=100
)
parser.add_argument(
"--n-features", type=int, help="Number of features", default=16
)
parser.add_argument("--n-graphs", type=int, help="Number of graphs", default=10)
parser.add_argument("--n-layers", type=int, help="Number of layers", default=30)
parser.add_argument(
"--n-nodes", type=int, help="Number of nodes", default=10000
)
parser.add_argument("--optim", type=str, help="Optimizer", default="Adam")
parser.add_argument("--radius", type=int, help="Radius", default=3)
parser.add_argument("--verbose", action="store_true")
args = parser.parse_args()
dev = th.device("cpu") if args.gpu < 0 else th.device("cuda:%d" % args.gpu)
K = args.n_communities
training_dataset = SBMMixtureDataset(args.n_graphs, args.n_nodes, K)
training_loader = DataLoader(
training_dataset,
args.batch_size,
collate_fn=training_dataset.collate_fn,
drop_last=True,
)
ones = th.ones(args.n_nodes // K)
y_list = [
th.cat([x * ones for x in p]).long().to(dev) for p in permutations(range(K))
]
feats = [1] + [args.n_features] * args.n_layers + [K]
model = gnn.GNN(feats, args.radius, K).to(dev)
optimizer = getattr(optim, args.optim)(model.parameters(), lr=args.lr)
def compute_overlap(z_list):
ybar_list = [th.max(z, 1)[1] for z in z_list]
overlap_list = []
for y_bar in ybar_list:
accuracy = max(th.sum(y_bar == y).item() for y in y_list) / args.n_nodes
overlap = (accuracy - 1 / K) / (1 - 1 / K)
overlap_list.append(overlap)
return sum(overlap_list) / len(overlap_list)
def from_np(f, *args):
def wrap(*args):
new = [
th.from_numpy(x) if isinstance(x, np.ndarray) else x for x in args
]
return f(*new)
return wrap
@from_np
def step(i, j, g, lg, deg_g, deg_lg, pm_pd):
"""One step of training."""
g = g.to(dev)
lg = lg.to(dev)
deg_g = deg_g.to(dev).unsqueeze(1)
deg_lg = deg_lg.to(dev).unsqueeze(1)
pm_pd = pm_pd.to(dev)
t0 = time.time()
z = model(g, lg, deg_g, deg_lg, pm_pd)
t_forward = time.time() - t0
z_list = th.chunk(z, args.batch_size, 0)
loss = (
sum(min(F.cross_entropy(z, y) for y in y_list) for z in z_list)
/ args.batch_size
)
overlap = compute_overlap(z_list)
optimizer.zero_grad()
t0 = time.time()
loss.backward()
t_backward = time.time() - t0
optimizer.step()
return loss, overlap, t_forward, t_backward
@from_np
def inference(g, lg, deg_g, deg_lg, pm_pd):
g = g.to(dev)
lg = lg.to(dev)
deg_g = deg_g.to(dev).unsqueeze(1)
deg_lg = deg_lg.to(dev).unsqueeze(1)
pm_pd = pm_pd.to(dev)
z = model(g, lg, deg_g, deg_lg, pm_pd)
return z
def test():
p_list = [6, 5.5, 5, 4.5, 1.5, 1, 0.5, 0]
q_list = [0, 0.5, 1, 1.5, 4.5, 5, 5.5, 6]
N = 1
overlap_list = []
for p, q in zip(p_list, q_list):
dataset = SBMMixtureDataset(N, args.n_nodes, K, pq=[[p, q]] * N)
loader = DataLoader(dataset, N, collate_fn=dataset.collate_fn)
g, lg, deg_g, deg_lg, pm_pd = next(iter(loader))
z = inference(g, lg, deg_g, deg_lg, pm_pd)
overlap_list.append(compute_overlap(th.chunk(z, N, 0)))
return overlap_list
n_iterations = args.n_graphs // args.batch_size
for i in range(args.n_epochs):
total_loss, total_overlap, s_forward, s_backward = 0, 0, 0, 0
for j, [g, lg, deg_g, deg_lg, pm_pd] in enumerate(training_loader):
loss, overlap, t_forward, t_backward = step(
i, j, g, lg, deg_g, deg_lg, pm_pd
)
total_loss += loss
total_overlap += overlap
s_forward += t_forward
s_backward += t_backward
epoch = "0" * (len(str(args.n_epochs)) - len(str(i)))
iteration = "0" * (len(str(n_iterations)) - len(str(j)))
if args.verbose:
print(
"[epoch %s%d iteration %s%d]loss %.3f | overlap %.3f"
% (epoch, i, iteration, j, loss, overlap)
)
epoch = "0" * (len(str(args.n_epochs)) - len(str(i)))
loss = total_loss / (j + 1)
overlap = total_overlap / (j + 1)
t_forward = s_forward / (j + 1)
t_backward = s_backward / (j + 1)
print(
"[epoch %s%d]loss %.3f | overlap %.3f | forward time %.3fs | backward time %.3fs"
% (epoch, i, loss, overlap, t_forward, t_backward)
)
overlap_list = test()
overlap_str = " - ".join(["%.3f" % overlap for overlap in overlap_list])
print("[epoch %s%d]overlap: %s" % (epoch, i, overlap_str))