[0.11.0] 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-Next-80B-A3B-Instruct",
              tensor_parallel_size=4,
              enforce_eager=True,
              trust_remote_code=True,
              max_model_len=256,
              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}")

[github-actions]

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[gemini-code-assist]

Code Review

This pull request addresses an accuracy issue in Qwen3-Next models when the 'nz' tensor format is enabled. The fix involves casting the convolution weights to a supported format before passing them to the causal_conv1d_update function. While the change is functionally correct, it introduces a magic number for the format cast, which harms code readability and maintainability. My review suggests replacing this magic number with a named constant, which should be imported from vllm_ascend.utils, and improving the related code comment for better clarity.

[gemini-code-assist]

The magic number 2 is used here for torch_npu.npu_format_cast. This makes the code hard to read and maintain. It's better to use a named constant. Based on other files in this repository, it seems 2 corresponds to ACL_FORMAT_FRACTAL_ND.

Please add from vllm_ascend.utils import ACL_FORMAT_FRACTAL_ND at the top of the file and use the constant here.

Also, the comment could be more descriptive about why this cast is necessary. I've included an improved comment in the suggestion.

Suggested change

	# qwen3-next not support nz
	torch_npu.npu_format_cast(conv_weights, 2),
	# The causal_conv1d_update kernel does not support the NZ format for conv_weights
	# with Qwen3-Next models. Casting to the ND format to ensure correctness.
	torch_npu.npu_format_cast(conv_weights, ACL_FORMAT_FRACTAL_ND),