[Doc] add embedding rerank doc (#7364)

docs/backend/native_api.ipynb

@@ -16,6 +16,7 @@
     "- `/flush_cache`\n",
     "- `/update_weights`\n",
     "- `/encode`(embedding model)\n",
+    "- `/v1/rerank`(cross encoder rerank model)\n",
     "- `/classify`(reward model)\n",
     "- `/start_expert_distribution_record`\n",
     "- `/stop_expert_distribution_record`\n",
@@ -307,6 +308,63 @@
     "terminate_process(embedding_process)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## v1/rerank (cross encoder rerank model)\n",
+    "Rerank a list of documents given a query using a cross-encoder model. Note that this API is only available for cross encoder model like [BAAI/bge-reranker-v2-m3](https://huggingface.co/BAAI/bge-reranker-v2-m3) with `attention-backend` `triton` and `torch_native`.\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "reranker_process, port = launch_server_cmd(\n",
+    "    \"\"\"\n",
+    "python3 -m sglang.launch_server --model-path BAAI/bge-reranker-v2-m3 \\\n",
+    "    --host 0.0.0.0 --disable-radix-cache --chunked-prefill-size -1 --attention-backend triton --is-embedding\n",
+    "\"\"\"\n",
+    ")\n",
+    "\n",
+    "wait_for_server(f\"http://localhost:{port}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# compute rerank scores for query and documents\n",
+    "\n",
+    "url = f\"http://localhost:{port}/v1/rerank\"\n",
+    "data = {\n",
+    "    \"model\": \"BAAI/bge-reranker-v2-m3\",\n",
+    "    \"query\": \"what is panda?\",\n",
+    "    \"documents\": [\n",
+    "        \"hi\",\n",
+    "        \"The giant panda (Ailuropoda melanoleuca), sometimes called a panda bear or simply panda, is a bear species endemic to China.\",\n",
+    "    ],\n",
+    "}\n",
+    "\n",
+    "response = requests.post(url, json=data)\n",
+    "response_json = response.json()\n",
+    "for item in response_json:\n",
+    "    print_highlight(f\"Score: {item['score']:.2f} - Document: '{item['document']}'\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "terminate_process(reranker_process)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -322,8 +380,6 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "terminate_process(embedding_process)\n",
-    "\n",
     "# Note that SGLang now treats embedding models and reward models as the same type of models.\n",
     "# This will be updated in the future.\n",
     "\n",