[Installation]: xformers issue

[seindum]

Your current environment

The output of `python collect_env.py`

How you are installing vllm

× No solution found when resolving dependencies:
╰─▶ Because there is no version of xformers{platform_machine ==
'x86_64' and sys_platform == 'linux'}==0.0.33+5d4b92a5.d20251029
and vllm==0.11.1rc6.dev12+gb2e65cb4a.precompiled depends on
xformers{platform_machine == 'x86_64' and sys_platform ==
'linux'}==0.0.33+5d4b92a5.d20251029, we can conclude that
vllm==0.11.1rc6.dev12+gb2e65cb4a.precompiled cannot be used.
And because only vllm==0.11.1rc6.dev12+gb2e65cb4a.precompiled is
available and you require vllm, we can conclude that your requirements
are unsatisfiable.

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[0xC45]

I am facing this same issue when trying to build from source.

$ uv venv --python 3.12 --seed
Using CPython 3.12.3 interpreter at: /usr/bin/python3.12
Creating virtual environment with seed packages at: .venv
 + pip==25.3
Activate with: source .venv/bin/activate

$ source .venv/bin/activate

$ uv pip install -e .
  × No solution found when resolving dependencies:
  ╰─▶ Because there is no version of xformers{platform_machine == 'x86_64' and sys_platform == 'linux'}==0.0.33+5d4b92a5.d20251029 and vllm==0.11.1rc6.dev12+gb2e65cb4a.d20251031.cu130 depends on xformers{platform_machine == 'x86_64' and
      sys_platform == 'linux'}==0.0.33+5d4b92a5.d20251029, we can conclude that vllm==0.11.1rc6.dev12+gb2e65cb4a.d20251031.cu130 cannot be used.
      And because only vllm==0.11.1rc6.dev12+gb2e65cb4a.d20251031.cu130 is available and you require vllm, we can conclude that your requirements are unsatisfiable.

Seems like #27768 could potentially be related? CC @huydhn

[gitover22]

maybe you can try again in a few minutes.

[seindum]

The wheel is not on PyPI but on PyTorch, so how I made it work is by adding --extra-index-url https://download.pytorch.org/whl/cu129 --index-strategy unsafe-best-match. I think the vLLM team should fix this though.

[youkaichao]

cc @huydhn

[Dingjifeng]

The wheel is not on PyPI but on PyTorch, so how I made it work is by adding --extra-index-url https://download.pytorch.org/whl/cu129 --index-strategy unsafe-best-match. I think the vLLM team should fix this though.

After i run

VLLM_USE_PRECOMPILED=1 uv pip install --editable . --extra-index-url https://download.pytorch.org/whl/cu129 --index-strategy unsafe-best-match

the terminal stuck at resolving dependencies

Using Python 3.10.0 environment at: /anaconda3/envs/vllm
⠇ Resolving dependencies...