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dmlc--dgl/examples/pytorch/ogb/directional_GSN/preprocessing.py
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2026-07-13 13:35:51 +08:00

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Python

import os
import graph_tool as gt
import graph_tool.topology as gt_topology
import networkx as nx
import numpy as np
import torch
from dgl.data.utils import load_graphs, save_graphs
from ogb.graphproppred import DglGraphPropPredDataset
from tqdm import tqdm
def to_undirected(edge_index):
row, col = edge_index.transpose(1, 0)
row, col = torch.cat([row, col], dim=0), torch.cat([col, row], dim=0)
edge_index = torch.stack([row, col], dim=0)
return edge_index.transpose(1, 0).tolist()
def induced_edge_automorphism_orbits(edge_list):
##### node automorphism orbits #####
graph = gt.Graph(directed=False)
graph.add_edge_list(edge_list)
gt.stats.remove_self_loops(graph)
gt.stats.remove_parallel_edges(graph)
# compute the node automorphism group
aut_group = gt_topology.subgraph_isomorphism(
graph, graph, induced=False, subgraph=True, generator=False
)
orbit_membership = {}
for v in graph.get_vertices():
orbit_membership[v] = v
# whenever two nodes can be mapped via some automorphism, they are assigned the same orbit
for aut in aut_group:
for original, node in enumerate(aut):
role = min(original, orbit_membership[node])
orbit_membership[node] = role
orbit_membership_list = [[], []]
for node, om_curr in orbit_membership.items():
orbit_membership_list[0].append(node)
orbit_membership_list[1].append(om_curr)
# make orbit list contiguous (i.e. 0,1,2,...O)
_, contiguous_orbit_membership = np.unique(
orbit_membership_list[1], return_inverse=True
)
orbit_membership = {
node: contiguous_orbit_membership[i]
for i, node in enumerate(orbit_membership_list[0])
}
aut_count = len(aut_group)
##### induced edge automorphism orbits (according to the node automorphism group) #####
edge_orbit_partition = dict()
edge_orbit_membership = dict()
edge_orbits2inds = dict()
ind = 0
edge_list = to_undirected(torch.tensor(graph.get_edges()))
# infer edge automorphisms from the node automorphisms
for i, edge in enumerate(edge_list):
edge_orbit = frozenset(
[orbit_membership[edge[0]], orbit_membership[edge[1]]]
)
if edge_orbit not in edge_orbits2inds:
edge_orbits2inds[edge_orbit] = ind
ind_edge_orbit = ind
ind += 1
else:
ind_edge_orbit = edge_orbits2inds[edge_orbit]
if ind_edge_orbit not in edge_orbit_partition:
edge_orbit_partition[ind_edge_orbit] = [tuple(edge)]
else:
edge_orbit_partition[ind_edge_orbit] += [tuple(edge)]
edge_orbit_membership[i] = ind_edge_orbit
print(
"Edge orbit partition of given substructure: {}".format(
edge_orbit_partition
)
)
print("Number of edge orbits: {}".format(len(edge_orbit_partition)))
print("Graph (node) automorphism count: {}".format(aut_count))
return graph, edge_orbit_partition, edge_orbit_membership, aut_count
def subgraph_isomorphism_edge_counts(edge_index, subgraph_dict):
##### edge structural identifiers #####
edge_index = edge_index.transpose(1, 0).cpu().numpy()
edge_dict = {}
for i, edge in enumerate(edge_index):
edge_dict[tuple(edge)] = i
subgraph_edges = to_undirected(
torch.tensor(subgraph_dict["subgraph"].get_edges().tolist())
)
G_gt = gt.Graph(directed=False)
G_gt.add_edge_list(list(edge_index))
gt.stats.remove_self_loops(G_gt)
gt.stats.remove_parallel_edges(G_gt)
# compute all subgraph isomorphisms
sub_iso = gt_topology.subgraph_isomorphism(
subgraph_dict["subgraph"],
G_gt,
induced=True,
subgraph=True,
generator=True,
)
counts = np.zeros(
(edge_index.shape[0], len(subgraph_dict["orbit_partition"]))
)
for sub_iso_curr in sub_iso:
mapping = sub_iso_curr.get_array()
for i, edge in enumerate(subgraph_edges):
# for every edge in the graph H, find the edge in the subgraph G_S to which it is mapped
# (by finding where its endpoints are matched).
# Then, increase the count of the matched edge w.r.t. the corresponding orbit
# Repeat for the reverse edge (the one with the opposite direction)
edge_orbit = subgraph_dict["orbit_membership"][i]
mapped_edge = tuple([mapping[edge[0]], mapping[edge[1]]])
counts[edge_dict[mapped_edge], edge_orbit] += 1
counts = counts / subgraph_dict["aut_count"]
counts = torch.tensor(counts)
return counts
def prepare_dataset(name):
# maximum size of cycle graph
k = 8
path = os.path.join("./", "dataset", name)
data_folder = os.path.join(path, "processed")
os.makedirs(data_folder, exist_ok=True)
data_file = os.path.join(
data_folder, "cycle_graph_induced_{}.bin".format(k)
)
# try to load
if os.path.exists(data_file): # load
print("Loading dataset from {}".format(data_file))
g_list, split_idx = load_graphs(data_file)
else: # generate
g_list, split_idx = generate_dataset(path, name)
print("Saving dataset to {}".format(data_file))
save_graphs(data_file, g_list, split_idx)
return g_list, split_idx
def generate_dataset(path, name):
### compute the orbits of each substructure in the list, as well as the node automorphism count
subgraph_dicts = []
edge_lists = []
for k in range(3, 8 + 1):
graphs_nx = nx.cycle_graph(k)
edge_lists.append(list(graphs_nx.edges))
for edge_list in edge_lists:
(
subgraph,
orbit_partition,
orbit_membership,
aut_count,
) = induced_edge_automorphism_orbits(edge_list=edge_list)
subgraph_dicts.append(
{
"subgraph": subgraph,
"orbit_partition": orbit_partition,
"orbit_membership": orbit_membership,
"aut_count": aut_count,
}
)
### load and preprocess dataset
dataset = DglGraphPropPredDataset(name=name, root=path)
split_idx = dataset.get_idx_split()
# computation of subgraph isomorphisms & creation of data structure
graphs_dgl = list()
split_idx["label"] = []
for i, datapoint in tqdm(enumerate(dataset)):
g, label = datapoint
g = _prepare(g, subgraph_dicts)
graphs_dgl.append(g)
split_idx["label"].append(label)
split_idx["label"] = torch.stack(split_idx["label"])
return graphs_dgl, split_idx
def _prepare(g, subgraph_dicts):
edge_index = torch.stack(g.edges())
identifiers = None
for subgraph_dict in subgraph_dicts:
counts = subgraph_isomorphism_edge_counts(edge_index, subgraph_dict)
identifiers = (
counts
if identifiers is None
else torch.cat((identifiers, counts), 1)
)
g.edata["subgraph_counts"] = identifiers.long()
return g
if __name__ == "__main__":
prepare_dataset("ogbg-molpcba")