[add] Create community nodes

2026-03-10 17:06:43 +08:00
parent 85770dc037
commit db8257b67a
5 changed files with 569 additions and 1 deletions
--- a/api/app/core/memory/storage_services/clustering_engine/init.py
+++ b/api/app/core/memory/storage_services/clustering_engine/init.py
@@ -0,0 +1,3 @@
+from app.core.memory.storage_services.clustering_engine.label_propagation import LabelPropagationEngine
+
+__all__ = ["LabelPropagationEngine"]
--- a/api/app/core/memory/storage_services/clustering_engine/label_propagation.py
+++ b/api/app/core/memory/storage_services/clustering_engine/label_propagation.py
@@ -0,0 +1,311 @@
+"""标签传播聚类引擎
+
+基于 ZEP 论文的动态标签传播算法，对 Neo4j 中的 ExtractedEntity 节点进行社区聚类。
+
+支持两种模式：
+- 全量初始化（full_clustering）：首次运行，对所有实体做完整 LPA 迭代
+- 增量更新（incremental_update）：新实体到达时，只处理新实体及其邻居
+"""
+
+import logging
+import uuid
+from math import sqrt
+from typing import Dict, List, Optional
+
+from app.repositories.neo4j.community_repository import CommunityRepository
+from app.repositories.neo4j.neo4j_connector import Neo4jConnector
+
+logger = logging.getLogger(__name__)
+
+# 全量迭代最大轮数，防止不收敛
+MAX_ITERATIONS = 10
+
+
+def _cosine_similarity(v1: Optional[List[float]], v2: Optional[List[float]]) -> float:
+    """计算两个向量的余弦相似度，任一为空则返回 0。"""
+    if not v1 or not v2 or len(v1) != len(v2):
+        return 0.0
+    dot = sum(a * b for a, b in zip(v1, v2))
+    norm1 = sqrt(sum(a * a for a in v1))
+    norm2 = sqrt(sum(b * b for b in v2))
+    if norm1 == 0 or norm2 == 0:
+        return 0.0
+    return dot / (norm1 * norm2)
+
+
+def _weighted_vote(
+    neighbors: List[Dict],
+    self_embedding: Optional[List[float]],
+) -> Optional[str]:
+    """
+    加权多数投票，选出得票最高的社区。
+
+    权重 = 语义相似度（name_embedding 余弦）* activation_value 加成
+    没有 community_id 的邻居不参与投票。
+    """
+    votes: Dict[str, float] = {}
+    for nb in neighbors:
+        cid = nb.get("community_id")
+        if not cid:
+            continue
+        sem = _cosine_similarity(self_embedding, nb.get("name_embedding"))
+        act = nb.get("activation_value") or 0.5
+        # 语义相似度权重 0.6，激活值权重 0.4
+        weight = 0.6 * sem + 0.4 * act
+        votes[cid] = votes.get(cid, 0.0) + weight
+
+    if not votes:
+        return None
+    return max(votes, key=votes.__getitem__)
+
+
+class LabelPropagationEngine:
+    """标签传播聚类引擎"""
+
+    def __init__(self, connector: Neo4jConnector):
+        self.connector = connector
+        self.repo = CommunityRepository(connector)
+
+    # ──────────────────────────────────────────────────────────────────────────
+    # 公开接口
+    # ──────────────────────────────────────────────────────────────────────────
+
+    async def run(
+        self,
+        end_user_id: str,
+        new_entity_ids: Optional[List[str]] = None,
+    ) -> None:
+        """
+        统一入口：自动判断全量还是增量。
+
+        - 若该用户尚无 Community 节点 → 全量初始化
+        - 否则 → 增量更新（仅处理 new_entity_ids）
+        """
+        has_communities = await self.repo.has_communities(end_user_id)
+        if not has_communities:
+            logger.info(f"[Clustering] 用户 {end_user_id} 首次聚类，执行全量初始化")
+            await self.full_clustering(end_user_id)
+        else:
+            if new_entity_ids:
+                logger.info(
+                    f"[Clustering] 增量更新，新实体数: {len(new_entity_ids)}"
+                )
+                await self.incremental_update(new_entity_ids, end_user_id)
+
+    async def full_clustering(self, end_user_id: str) -> None:
+        """
+        全量标签传播初始化。
+
+        1. 拉取所有实体，初始化每个实体为独立社区
+        2. 迭代：每轮对所有实体做邻居投票，更新社区标签
+        3. 直到标签不再变化或达到 MAX_ITERATIONS
+        4. 将最终标签写入 Neo4j
+        """
+        entities = await self.repo.get_all_entities(end_user_id)
+        if not entities:
+            logger.info(f"[Clustering] 用户 {end_user_id} 无实体，跳过全量聚类")
+            return
+
+        # 初始化：每个实体持有自己 id 作为社区标签
+        labels: Dict[str, str] = {e["id"]: e["id"] for e in entities}
+        embeddings: Dict[str, Optional[List[float]]] = {
+            e["id"]: e.get("name_embedding") for e in entities
+        }
+
+        for iteration in range(MAX_ITERATIONS):
+            changed = 0
+            # 随机顺序（Python dict 在 3.7+ 保持插入顺序，这里直接遍历）
+            for entity in entities:
+                eid = entity["id"]
+                neighbors = await self.repo.get_entity_neighbors(eid, end_user_id)
+
+                # 将邻居的当前内存标签注入（覆盖 Neo4j 中的旧值）
+                enriched = []
+                for nb in neighbors:
+                    nb_copy = dict(nb)
+                    nb_copy["community_id"] = labels.get(nb["id"], nb.get("community_id"))
+                    enriched.append(nb_copy)
+
+                new_label = _weighted_vote(enriched, embeddings.get(eid))
+                if new_label and new_label != labels[eid]:
+                    labels[eid] = new_label
+                    changed += 1
+
+            logger.info(
+                f"[Clustering] 全量迭代 {iteration + 1}/{MAX_ITERATIONS}，"
+                f"标签变化数: {changed}"
+            )
+            if changed == 0:
+                logger.info("[Clustering] 标签已收敛，提前结束迭代")
+                break
+
+        # 将最终标签写入 Neo4j
+        await self._flush_labels(labels, end_user_id)
+        logger.info(
+            f"[Clustering] 全量聚类完成，共 {len(set(labels.values()))} 个社区，"
+            f"{len(labels)} 个实体"
+        )
+
+    async def incremental_update(
+        self, new_entity_ids: List[str], end_user_id: str
+    ) -> None:
+        """
+        增量更新：只处理新实体及其邻居，不重跑全图。
+
+        1. 对每个新实体查询邻居
+        2. 加权多数投票决定社区归属
+        3. 若邻居无社区 → 创建新社区
+        4. 若邻居分属多个社区 → 评估是否合并
+        """
+        for entity_id in new_entity_ids:
+            await self._process_single_entity(entity_id, end_user_id)
+
+    # ──────────────────────────────────────────────────────────────────────────
+    # 内部方法
+    # ──────────────────────────────────────────────────────────────────────────
+
+    async def _process_single_entity(
+        self, entity_id: str, end_user_id: str
+    ) -> None:
+        """处理单个新实体的社区分配。"""
+        neighbors = await self.repo.get_entity_neighbors(entity_id, end_user_id)
+
+        # 查询自身 embedding（从邻居查询结果中无法获取，需单独查）
+        self_embedding = await self._get_entity_embedding(entity_id, end_user_id)
+
+        if not neighbors:
+            # 孤立实体：创建单成员社区
+            new_cid = self._new_community_id()
+            await self.repo.upsert_community(new_cid, end_user_id, member_count=1)
+            await self.repo.assign_entity_to_community(entity_id, new_cid, end_user_id)
+            logger.debug(f"[Clustering] 孤立实体 {entity_id} → 新社区 {new_cid}")
+            return
+
+        # 统计邻居社区分布
+        community_ids_in_neighbors = set(
+            nb["community_id"] for nb in neighbors if nb.get("community_id")
+        )
+
+        target_cid = _weighted_vote(neighbors, self_embedding)
+
+        if target_cid is None:
+            # 邻居都没有社区，连同新实体一起创建新社区
+            new_cid = self._new_community_id()
+            await self.repo.upsert_community(new_cid, end_user_id)
+            await self.repo.assign_entity_to_community(entity_id, new_cid, end_user_id)
+            for nb in neighbors:
+                await self.repo.assign_entity_to_community(
+                    nb["id"], new_cid, end_user_id
+                )
+            await self.repo.refresh_member_count(new_cid, end_user_id)
+            logger.debug(
+                f"[Clustering] 新实体 {entity_id} 与 {len(neighbors)} 个无社区邻居 → 新社区 {new_cid}"
+            )
+        else:
+            # 加入得票最多的社区
+            await self.repo.assign_entity_to_community(entity_id, target_cid, end_user_id)
+            await self.repo.refresh_member_count(target_cid, end_user_id)
+            logger.debug(f"[Clustering] 新实体 {entity_id} → 社区 {target_cid}")
+
+            # 若邻居分属多个社区，评估合并
+            if len(community_ids_in_neighbors) > 1:
+                await self._evaluate_merge(
+                    list(community_ids_in_neighbors), end_user_id
+                )
+
+    async def _evaluate_merge(
+        self, community_ids: List[str], end_user_id: str
+    ) -> None:
+        """
+        评估多个社区是否应合并。
+
+        策略：计算各社区成员 embedding 的平均向量，若两两余弦相似度 > 0.75 则合并。
+        合并时保留成员数最多的社区，其余成员迁移过来。
+        """
+        MERGE_THRESHOLD = 0.75
+
+        community_embeddings: Dict[str, Optional[List[float]]] = {}
+        community_sizes: Dict[str, int] = {}
+
+        for cid in community_ids:
+            members = await self.repo.get_community_members(cid, end_user_id)
+            community_sizes[cid] = len(members)
+            # 计算社区成员 embedding 的平均向量
+            valid_embeddings = [
+                m["name_embedding"]
+                for m in members
+                if m.get("name_embedding")
+            ]
+            if valid_embeddings:
+                dim = len(valid_embeddings[0])
+                avg = [
+                    sum(e[i] for e in valid_embeddings) / len(valid_embeddings)
+                    for i in range(dim)
+                ]
+                community_embeddings[cid] = avg
+            else:
+                community_embeddings[cid] = None
+
+        # 找出应合并的社区对
+        to_merge: List[tuple] = []
+        cids = list(community_ids)
+        for i in range(len(cids)):
+            for j in range(i + 1, len(cids)):
+                sim = _cosine_similarity(
+                    community_embeddings[cids[i]],
+                    community_embeddings[cids[j]],
+                )
+                if sim > MERGE_THRESHOLD:
+                    to_merge.append((cids[i], cids[j]))
+
+        for c1, c2 in to_merge:
+            keep = c1 if community_sizes.get(c1, 0) >= community_sizes.get(c2, 0) else c2
+            dissolve = c2 if keep == c1 else c1
+            members = await self.repo.get_community_members(dissolve, end_user_id)
+            for m in members:
+                await self.repo.assign_entity_to_community(
+                    m["id"], keep, end_user_id
+                )
+            await self.repo.refresh_member_count(keep, end_user_id)
+            logger.info(
+                f"[Clustering] 社区合并: {dissolve} → {keep}，"
+                f"迁移 {len(members)} 个成员"
+            )
+
+    async def _flush_labels(
+        self, labels: Dict[str, str], end_user_id: str
+    ) -> None:
+        """将内存中的标签批量写入 Neo4j。"""
+        # 先创建所有唯一社区节点
+        unique_communities = set(labels.values())
+        for cid in unique_communities:
+            await self.repo.upsert_community(cid, end_user_id)
+
+        # 再批量分配实体
+        for entity_id, community_id in labels.items():
+            await self.repo.assign_entity_to_community(
+                entity_id, community_id, end_user_id
+            )
+
+        # 刷新成员数
+        for cid in unique_communities:
+            await self.repo.refresh_member_count(cid, end_user_id)
+
+    async def _get_entity_embedding(
+        self, entity_id: str, end_user_id: str
+    ) -> Optional[List[float]]:
+        """查询单个实体的 name_embedding。"""
+        try:
+            result = await self.connector.execute_query(
+                "MATCH (e:ExtractedEntity {id: $eid, end_user_id: $uid}) "
+                "RETURN e.name_embedding AS name_embedding",
+                eid=entity_id,
+                uid=end_user_id,
+            )
+            return result[0]["name_embedding"] if result else None
+        except Exception:
+            return None
+
+    @staticmethod
+    def _new_community_id() -> str:
+        return str(uuid.uuid4())