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

301 lines
9.0 KiB
Python

import os.path as osp
from copy import deepcopy
import dgl
import torch
from dgl import add_self_loop, DGLGraph, NID
from dgl.dataloading.negative_sampler import Uniform
from torch.utils.data import DataLoader, Dataset
from tqdm import tqdm
from utils import drnl_node_labeling
class GraphDataSet(Dataset):
"""
GraphDataset for torch DataLoader
"""
def __init__(self, graph_list, tensor):
self.graph_list = graph_list
self.tensor = tensor
def __len__(self):
return len(self.graph_list)
def __getitem__(self, index):
return (self.graph_list[index], self.tensor[index])
class PosNegEdgesGenerator(object):
"""
Generate positive and negative samples
Attributes:
g(dgl.DGLGraph): graph
split_edge(dict): split edge
neg_samples(int): num of negative samples per positive sample
subsample_ratio(float): ratio of subsample
shuffle(bool): if shuffle generated graph list
"""
def __init__(
self, g, split_edge, neg_samples=1, subsample_ratio=0.1, shuffle=True
):
self.neg_sampler = Uniform(neg_samples)
self.subsample_ratio = subsample_ratio
self.split_edge = split_edge
self.g = g
self.shuffle = shuffle
def __call__(self, split_type):
if split_type == "train":
subsample_ratio = self.subsample_ratio
else:
subsample_ratio = 1
pos_edges = self.split_edge[split_type]["edge"]
if split_type == "train":
# Adding self loop in train avoids sampling the source node itself.
g = add_self_loop(self.g)
eids = g.edge_ids(pos_edges[:, 0], pos_edges[:, 1])
neg_edges = torch.stack(self.neg_sampler(g, eids), dim=1)
else:
neg_edges = self.split_edge[split_type]["edge_neg"]
pos_edges = self.subsample(pos_edges, subsample_ratio).long()
neg_edges = self.subsample(neg_edges, subsample_ratio).long()
edges = torch.cat([pos_edges, neg_edges])
labels = torch.cat(
[
torch.ones(pos_edges.size(0), 1),
torch.zeros(neg_edges.size(0), 1),
]
)
if self.shuffle:
perm = torch.randperm(edges.size(0))
edges = edges[perm]
labels = labels[perm]
return edges, labels
def subsample(self, edges, subsample_ratio):
"""
Subsample generated edges.
Args:
edges(Tensor): edges to subsample
subsample_ratio(float): ratio of subsample
Returns:
edges(Tensor): edges
"""
num_edges = edges.size(0)
perm = torch.randperm(num_edges)
perm = perm[: int(subsample_ratio * num_edges)]
edges = edges[perm]
return edges
class EdgeDataSet(Dataset):
"""
Assistant Dataset for speeding up the SEALSampler
"""
def __init__(self, edges, labels, transform):
self.edges = edges
self.transform = transform
self.labels = labels
def __len__(self):
return len(self.edges)
def __getitem__(self, index):
subgraph = self.transform(self.edges[index])
return (subgraph, self.labels[index])
class SEALSampler(object):
"""
Sampler for SEAL in paper(no-block version)
The strategy is to sample all the k-hop neighbors around the two target nodes.
Attributes:
graph(DGLGraph): The graph
hop(int): num of hop
num_workers(int): num of workers
"""
def __init__(self, graph, hop=1, num_workers=32, print_fn=print):
self.graph = graph
self.hop = hop
self.print_fn = print_fn
self.num_workers = num_workers
def sample_subgraph(self, target_nodes):
"""
Args:
target_nodes(Tensor): Tensor of two target nodes
Returns:
subgraph(DGLGraph): subgraph
"""
sample_nodes = [target_nodes]
frontiers = target_nodes
for i in range(self.hop):
frontiers = self.graph.out_edges(frontiers)[1]
frontiers = torch.unique(frontiers)
sample_nodes.append(frontiers)
sample_nodes = torch.cat(sample_nodes)
sample_nodes = torch.unique(sample_nodes)
subgraph = dgl.node_subgraph(self.graph, sample_nodes)
# Each node should have unique node id in the new subgraph
u_id = int(
torch.nonzero(
subgraph.ndata[NID] == int(target_nodes[0]), as_tuple=False
)
)
v_id = int(
torch.nonzero(
subgraph.ndata[NID] == int(target_nodes[1]), as_tuple=False
)
)
# remove link between target nodes in positive subgraphs.
if subgraph.has_edges_between(u_id, v_id):
link_id = subgraph.edge_ids(u_id, v_id, return_uv=True)[2]
subgraph.remove_edges(link_id)
if subgraph.has_edges_between(v_id, u_id):
link_id = subgraph.edge_ids(v_id, u_id, return_uv=True)[2]
subgraph.remove_edges(link_id)
z = drnl_node_labeling(subgraph, u_id, v_id)
subgraph.ndata["z"] = z
return subgraph
def _collate(self, batch):
batch_graphs, batch_labels = map(list, zip(*batch))
batch_graphs = dgl.batch(batch_graphs)
batch_labels = torch.stack(batch_labels)
return batch_graphs, batch_labels
def __call__(self, edges, labels):
subgraph_list = []
labels_list = []
edge_dataset = EdgeDataSet(
edges, labels, transform=self.sample_subgraph
)
self.print_fn(
"Using {} workers in sampling job.".format(self.num_workers)
)
sampler = DataLoader(
edge_dataset,
batch_size=32,
num_workers=self.num_workers,
shuffle=False,
collate_fn=self._collate,
)
for subgraph, label in tqdm(sampler, ncols=100):
label_copy = deepcopy(label)
subgraph = dgl.unbatch(subgraph)
del label
subgraph_list += subgraph
labels_list.append(label_copy)
return subgraph_list, torch.cat(labels_list)
class SEALData(object):
"""
1. Generate positive and negative samples
2. Subgraph sampling
Attributes:
g(dgl.DGLGraph): graph
split_edge(dict): split edge
hop(int): num of hop
neg_samples(int): num of negative samples per positive sample
subsample_ratio(float): ratio of subsample
use_coalesce(bool): True for coalesce graph. Graph with multi-edge need to coalesce
"""
def __init__(
self,
g,
split_edge,
hop=1,
neg_samples=1,
subsample_ratio=1,
prefix=None,
save_dir=None,
num_workers=32,
shuffle=True,
use_coalesce=True,
print_fn=print,
):
self.g = g
self.hop = hop
self.subsample_ratio = subsample_ratio
self.prefix = prefix
self.save_dir = save_dir
self.print_fn = print_fn
self.generator = PosNegEdgesGenerator(
g=self.g,
split_edge=split_edge,
neg_samples=neg_samples,
subsample_ratio=subsample_ratio,
shuffle=shuffle,
)
if use_coalesce:
for k, v in g.edata.items():
g.edata[k] = v.float() # dgl.to_simple() requires data is float
self.g = dgl.to_simple(
g, copy_ndata=True, copy_edata=True, aggregator="sum"
)
self.ndata = {k: v for k, v in self.g.ndata.items()}
self.edata = {k: v for k, v in self.g.edata.items()}
self.g.ndata.clear()
self.g.edata.clear()
self.print_fn("Save ndata and edata in class.")
self.print_fn("Clear ndata and edata in graph.")
self.sampler = SEALSampler(
graph=self.g, hop=hop, num_workers=num_workers, print_fn=print_fn
)
def __call__(self, split_type):
if split_type == "train":
subsample_ratio = self.subsample_ratio
else:
subsample_ratio = 1
path = osp.join(
self.save_dir or "",
"{}_{}_{}-hop_{}-subsample.bin".format(
self.prefix, split_type, self.hop, subsample_ratio
),
)
if osp.exists(path):
self.print_fn("Load existing processed {} files".format(split_type))
graph_list, data = dgl.load_graphs(path)
dataset = GraphDataSet(graph_list, data["labels"])
else:
self.print_fn("Processed {} files not exist.".format(split_type))
edges, labels = self.generator(split_type)
self.print_fn("Generate {} edges totally.".format(edges.size(0)))
graph_list, labels = self.sampler(edges, labels)
dataset = GraphDataSet(graph_list, labels)
dgl.save_graphs(path, graph_list, {"labels": labels})
self.print_fn("Save preprocessed subgraph to {}".format(path))
return dataset