Fix: bug #991 (#1013)

### What problem does this PR solve?

issue #991

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: KevinHuSh <kevinhu.sh@gmail.com>

api/db/init_data.py

@@ -386,7 +386,7 @@ def init_llm_factory():
             "fid": factory_infos[7]["name"],
             "llm_name": "maidalun1020/bce-reranker-base_v1",
             "tags": "RE-RANK, 8K",
-            "max_tokens": 8196,
+            "max_tokens": 512,
             "model_type": LLMType.RERANK.value
         },
         # ------------------------ DeepSeek -----------------------

rag/llm/rerank_model.py

@@ -113,4 +113,18 @@ class YoudaoRerank(DefaultRerank):
                 YoudaoRerank._model = RerankerModel(
                     model_name_or_path=model_name.replace(
                         "maidalun1020", "InfiniFlow"))
+    
+    def similarity(self, query: str, texts: list):
+        pairs = [(query,truncate(t, self._model.max_length)) for t in texts]
+        token_count = 0
+        for _, t in pairs:
+            token_count += num_tokens_from_string(t)
+        batch_size = 32
+        res = []
+        for i in range(0, len(pairs), batch_size):
+            scores = self._model.compute_score(pairs[i:i + batch_size], max_length=self._model.max_length)
+            scores = sigmoid(np.array(scores)).tolist()
+            res.extend(scores)
+        return np.array(res), token_count
+