[BugFix] Fixes Qwen3-Next enable nz accuracy problem

[wxsIcey]

What this PR does / why we need it?

• Fixes Qwen3-Next enable nz accuracy problem

Does this PR introduce any user-facing change?

N/A

How was this patch tested?

def main():
    prompts = [
        "窗前明月光，",
        "The president of the United States is Mr.",
        "The capital of France is",
        "The future of AI is",
        "感时花溅泪，",
        "家书抵万金啥意思？",
        "plz tell me a story: ",
    ]

    # Create a sampling params object.
    sampling_params = SamplingParams(max_tokens=100, temperature=0.6, top_k=40, top_p=0.95)
    # Create an LLM.
    llm = LLM(
        # model="/root/.cache/modelscope/hub/models/Qwen/Qwen3-30B-A3B",
        model="Qwen/Qwen3-Next-80B-A3B-Instruct",
              tensor_parallel_size=4,
              enforce_eager=True,
              trust_remote_code=True,
              max_model_len=256,
              # max_num_seqs=2,
              gpu_memory_utilization=0.7,
              block_size=64,
              )

    # Generate texts from the prompts.
    outputs = llm.generate(prompts, sampling_params)
    for output in outputs:
        prompt = output.prompt
        generated_text = output.outputs[0].text
        print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")

• vLLM version: v0.11.0
• vLLM main: vllm-project/vllm@83f478b

[github-actions]

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[gemini-code-assist]

Code Review

This pull request addresses an accuracy issue with the Qwen3-Next model when the NZ format is enabled. The fix involves explicitly casting the conv_weights tensor to the ND format to disable the NZ format optimization. The change is straightforward and seems to be an effective workaround. My review includes a suggestion to improve the code's readability and maintainability by replacing a magic number with a named constant and clarifying the associated comment.

[gemini-code-assist]

The comment has a typo ("accuray") and could be more descriptive. Also, the magic number 2 is used, which refers to ACL_FORMAT_FRACTAL_ND. It would be best to import and use the constant from vllm_ascend.utils for better readability and maintainability.

Since I cannot add the import myself, I've included the constant name in the comment within the suggestion. Please consider importing and using the constant.

Suggested change

	# qwen3-next enable nz has accuray problems, so disable it here
	torch_npu.npu_format_cast(conv_weights, 2),
	# Workaround for Qwen3-Next accuracy issue with NZ format by casting to ND (ACL_FORMAT_FRACTAL_ND).
	torch_npu.npu_format_cast(conv_weights, 2),