add metax sentence-transformers engine

Signed-off-by: Sun Ruoxi <sunruoxi@4paradigm.com>

server.py

@@ -0,0 +1,51 @@
+from fastapi import FastAPI
+from pydantic import BaseModel
+from typing import List
+import numpy as np
+
+from sentence_transformers import SentenceTransformer
+
+# ===== 配置 =====
+MODEL_NAME = "/model"
+DEVICE = "cuda"  # 改成国产卡设备，例如 "npu" / "mlu" / "cpu"
+
+# ===== 加载模型 =====
+model = SentenceTransformer(MODEL_NAME, device=DEVICE)
+
+app = FastAPI()
+
+# ===== 请求结构 =====
+class EncodeRequest(BaseModel):
+    texts: List[str]
+    normalize: bool = True
+
+class SimilarityRequest(BaseModel):
+    text1: str
+    text2: str
+
+# ===== 工具函数 =====
+def cosine(a, b):
+    return float(np.dot(a, b) / (np.linalg.norm(a) * np.linalg.norm(b)))
+
+# ===== 接口 =====
+@app.post("/encode")
+def encode(req: EncodeRequest):
+    embeddings = model.encode(
+        req.texts,
+        normalize_embeddings=req.normalize
+    )
+    return {
+        "embeddings": embeddings.tolist()
+    }
+
+@app.post("/similarity")
+def similarity(req: SimilarityRequest):
+    emb = model.encode([req.text1, req.text2], normalize_embeddings=True)
+    sim = cosine(emb[0], emb[1])
+    return {
+        "similarity": sim
+    }
+
+@app.get("/health")
+def health():
+    return {"status": "ok"}