update hybrid_retriever_tool file

tools/hybrid_retriever_tool.py

@@ -47,8 +47,8 @@ class HybridRetrieverTool(RagTool):
         sem_scores = np.dot(emb_corpus, emb_query)
 
         # Normalize scores
-        bm25_norm = (bm25_scores - bm25_scores.min()) / (bm25_scores.ptp() + 1e-8)
-        sem_norm = (sem_scores - sem_scores.min()) / (sem_scores.ptp() + 1e-8)
+        bm25_norm = (bm25_scores - bm25_scores.min()) / (np.ptp(bm25_scores) + 1e-8)
+        sem_norm = (sem_scores - sem_scores.min()) / (np.ptp(sem_scores) + 1e-8)
 
         # Weighted fusion
         hybrid_scores = self.alpha * sem_norm + (1 - self.alpha) * bm25_norm