ragflow / graphrag /leiden.py
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#
# Copyright 2024 The InfiniFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""
Reference:
- [graphrag](https://github.com/microsoft/graphrag)
"""
import logging
from typing import Any, cast, List
import html
from graspologic.partition import hierarchical_leiden
from graspologic.utils import largest_connected_component
import networkx as nx
from networkx import is_empty
log = logging.getLogger(__name__)
def _stabilize_graph(graph: nx.Graph) -> nx.Graph:
"""Ensure an undirected graph with the same relationships will always be read the same way."""
fixed_graph = nx.DiGraph() if graph.is_directed() else nx.Graph()
sorted_nodes = graph.nodes(data=True)
sorted_nodes = sorted(sorted_nodes, key=lambda x: x[0])
fixed_graph.add_nodes_from(sorted_nodes)
edges = list(graph.edges(data=True))
# If the graph is undirected, we create the edges in a stable way, so we get the same results
# for example:
# A -> B
# in graph theory is the same as
# B -> A
# in an undirected graph
# however, this can lead to downstream issues because sometimes
# consumers read graph.nodes() which ends up being [A, B] and sometimes it's [B, A]
# but they base some of their logic on the order of the nodes, so the order ends up being important
# so we sort the nodes in the edge in a stable way, so that we always get the same order
if not graph.is_directed():
def _sort_source_target(edge):
source, target, edge_data = edge
if source > target:
temp = source
source = target
target = temp
return source, target, edge_data
edges = [_sort_source_target(edge) for edge in edges]
def _get_edge_key(source: Any, target: Any) -> str:
return f"{source} -> {target}"
edges = sorted(edges, key=lambda x: _get_edge_key(x[0], x[1]))
fixed_graph.add_edges_from(edges)
return fixed_graph
def normalize_node_names(graph: nx.Graph | nx.DiGraph) -> nx.Graph | nx.DiGraph:
"""Normalize node names."""
node_mapping = {node: html.unescape(node.upper().strip()) for node in graph.nodes()} # type: ignore
return nx.relabel_nodes(graph, node_mapping)
def stable_largest_connected_component(graph: nx.Graph) -> nx.Graph:
"""Return the largest connected component of the graph, with nodes and edges sorted in a stable way."""
graph = graph.copy()
graph = cast(nx.Graph, largest_connected_component(graph))
graph = normalize_node_names(graph)
return _stabilize_graph(graph)
def _compute_leiden_communities(
graph: nx.Graph | nx.DiGraph,
max_cluster_size: int,
use_lcc: bool,
seed=0xDEADBEEF,
) -> dict[int, dict[str, int]]:
"""Return Leiden root communities."""
results: dict[int, dict[str, int]] = {}
if is_empty(graph): return results
if use_lcc:
graph = stable_largest_connected_component(graph)
community_mapping = hierarchical_leiden(
graph, max_cluster_size=max_cluster_size, random_seed=seed
)
for partition in community_mapping:
results[partition.level] = results.get(partition.level, {})
results[partition.level][partition.node] = partition.cluster
return results
def run(graph: nx.Graph, args: dict[str, Any]) -> dict[int, dict[str, dict]]:
"""Run method definition."""
max_cluster_size = args.get("max_cluster_size", 12)
use_lcc = args.get("use_lcc", True)
if args.get("verbose", False):
log.info(
"Running leiden with max_cluster_size=%s, lcc=%s", max_cluster_size, use_lcc
)
if not graph.nodes(): return {}
node_id_to_community_map = _compute_leiden_communities(
graph=graph,
max_cluster_size=max_cluster_size,
use_lcc=use_lcc,
seed=args.get("seed", 0xDEADBEEF),
)
levels = args.get("levels")
# If they don't pass in levels, use them all
if levels is None:
levels = sorted(node_id_to_community_map.keys())
results_by_level: dict[int, dict[str, list[str]]] = {}
for level in levels:
result = {}
results_by_level[level] = result
for node_id, raw_community_id in node_id_to_community_map[level].items():
community_id = str(raw_community_id)
if community_id not in result:
result[community_id] = {"weight": 0, "nodes": []}
result[community_id]["nodes"].append(node_id)
result[community_id]["weight"] += graph.nodes[node_id].get("rank", 0) * graph.nodes[node_id].get("weight", 1)
weights = [comm["weight"] for _, comm in result.items()]
if not weights:continue
max_weight = max(weights)
for _, comm in result.items(): comm["weight"] /= max_weight
return results_by_level
def add_community_info2graph(graph: nx.Graph, commu_info: dict[str, dict[str, dict]]):
for lev, cluster_info in commu_info.items():
for cid, nodes in cluster_info.items():
for n in nodes["nodes"]:
if "community" not in graph.nodes[n]: graph.nodes[n]["community"] = {}
graph.nodes[n]["community"].update({lev: cid})
def add_community_info2graph(graph: nx.Graph, nodes: List[str], community_title):
for n in nodes:
if "communities" not in graph.nodes[n]:
graph.nodes[n]["communities"] = []
graph.nodes[n]["communities"].append(community_title)