[New Model]: Support Qwen3 Embedding & Reranker (#19260)

examples/offline_inference/qwen3_reranker.py

@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# ruff: noqa: E501
+
+from vllm import LLM
+
+model_name = "Qwen/Qwen3-Reranker-0.6B"
+
+# What is the difference between the official original version and one
+# that has been converted into a sequence classification model?
+# Qwen3-Reranker is a language model that doing reranker by using the
+# logits of "no" and "yes" tokens.
+# It needs to computing 151669 tokens logits, making this method extremely
+# inefficient, not to mention incompatible with the vllm score API.
+# A method for converting the original model into a sequence classification
+# model was proposed. See：https://huggingface.co/Qwen/Qwen3-Reranker-0.6B/discussions/3
+# Models converted offline using this method can not only be more efficient
+# and support the vllm score API, but also make the init parameters more
+# concise, for example.
+# model = LLM(model="tomaarsen/Qwen3-Reranker-0.6B-seq-cls", task="score")
+
+# If you want to load the official original version, the init parameters are
+# as follows.
+
+model = LLM(
+    model=model_name,
+    task="score",
+    hf_overrides={
+        "architectures": ["Qwen3ForSequenceClassification"],
+        "classifier_from_token": ["no", "yes"],
+        "is_original_qwen3_reranker": True,
+    },
+)
+
+# Why do we need hf_overrides for the official original version:
+# vllm converts it to Qwen3ForSequenceClassification when loaded for
+# better performance.
+# - Firstly, we need using `"architectures": ["Qwen3ForSequenceClassification"],`
+# to manually route to Qwen3ForSequenceClassification.
+# - Then, we will extract the vector corresponding to classifier_from_token
+# from lm_head using `"classifier_from_token": ["no", "yes"]`.
+# - Third, we will convert these two vectors into one vector.  The use of
+# conversion logic is controlled by `using "is_original_qwen3_reranker": True`.
+
+# Please use the query_template and document_template to format the query and
+# document for better reranker results.
+
+prefix = '<|im_start|>system\nJudge whether the Document meets the requirements based on the Query and the Instruct provided. Note that the answer can only be "yes" or "no".<|im_end|>\n<|im_start|>user\n'
+suffix = "<|im_end|>\n<|im_start|>assistant\n<think>\n\n</think>\n\n"
+
+query_template = "{prefix}<Instruct>: {instruction}\n<Query>: {query}\n"
+document_template = "<Document>: {doc}{suffix}"
+
+if __name__ == "__main__":
+    instruction = (
+        "Given a web search query, retrieve relevant passages that answer the query"
+    )
+
+    queries = [
+        "What is the capital of China?",
+        "Explain gravity",
+    ]
+
+    documents = [
+        "The capital of China is Beijing.",
+        "Gravity is a force that attracts two bodies towards each other. It gives weight to physical objects and is responsible for the movement of planets around the sun.",
+    ]
+
+    queries = [
+        query_template.format(prefix=prefix, instruction=instruction, query=query)
+        for query in queries
+    ]
+    documents = [document_template.format(doc=doc, suffix=suffix) for doc in documents]
+
+    outputs = model.score(queries, documents)
+
+    print([output.outputs.score for output in outputs])