| 1 | # SPDX-License-Identifier: Apache-2.0 |
| 2 | # SPDX-FileCopyrightText: Copyright contributors to the vLLM project |
| 3 | |
| 4 | from vllm import LLM, RequestOutput, SamplingParams |
| 5 | |
| 6 | # Sample prompts. |
| 7 | prompts = [ |
| 8 | "Hello, my name is", |
| 9 | "The president of the United States is", |
| 10 | "The capital of France is", |
| 11 | "The future of AI is", |
| 12 | ] |
| 13 | # Create a sampling params object. |
| 14 | sampling_params = SamplingParams(temperature=0.8, top_p=0.95) |
| 15 | |
| 16 | |
| 17 | def print_prompts_and_outputs(outputs: list[RequestOutput]) -> None: |
| 18 | print("-" * 60) |
| 19 | for output in outputs: |
| 20 | prompt = output.prompt |
| 21 | generated_text = output.outputs[0].text |
| 22 | print(f"Prompt: {prompt!r}") |
| 23 | print(f"Output: {generated_text!r}") |
| 24 | print("-" * 60) |
| 25 | |
| 26 | |
| 27 | def main(): |
| 28 | # Create an LLM without loading real weights |
| 29 | llm = LLM( |
| 30 | model="Qwen/Qwen3-0.6B", |
| 31 | load_format="dummy", |
| 32 | enforce_eager=True, |
| 33 | tensor_parallel_size=4, |
| 34 | ) |
| 35 | outputs = llm.generate(prompts, sampling_params) |
| 36 | print("\nOutputs do not make sense:") |
| 37 | print_prompts_and_outputs(outputs) |
| 38 | |
| 39 | # Update load format from `dummy` to `auto` |
| 40 | llm.collective_rpc( |
| 41 | "update_config", args=({"load_config": {"load_format": "auto"}},) |
| 42 | ) |
| 43 | # Now reload real weights inplace |
| 44 | llm.collective_rpc("reload_weights") |
| 45 | |
| 46 | # Check outputs make sense |
| 47 | outputs = llm.generate(prompts, sampling_params) |
| 48 | print("\nOutputs make sense after loading real weights:") |
| 49 | print_prompts_and_outputs(outputs) |
| 50 | |
| 51 | |
| 52 | if __name__ == "__main__": |
| 53 | main() |