Unable to install flash-attn even if I first install torch alone

[ytxmobile98]

My environment:

• OS: Ubuntu 24.04.1 LTS
• Python version: 3.10.15
• PIP version: 24.3.1
• Torch version: 2.5.1

It came to my attention that pip install flash_attn does not work. When I try it, the error I got is: No module named 'torch'.

This issue happens even if I install torch first, then install flash-attn afterwards.

$ pip install flash-attn
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple/
Collecting flash-attn
  Using cached https://pypi.tuna.tsinghua.edu.cn/packages/83/29/48df18cb51902a7cb7a0ee13327bb2cf50b6ba24bd2e8283d0a9538dde52/flash_attn-2.7.2.post1.tar.gz (3.1 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  error: subprocess-exited-with-error
  
  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [17 lines of output]
      Traceback (most recent call last):
        File "/home/tianxing/1/.venv/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/home/tianxing/1/.venv/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
        File "/home/tianxing/1/.venv/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 118, in get_requires_for_build_wheel
          return hook(config_settings)
        File "/tmp/pip-build-env-k5ezeotm/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 334, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=[])
        File "/tmp/pip-build-env-k5ezeotm/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 304, in _get_build_requires
          self.run_setup()
        File "/tmp/pip-build-env-k5ezeotm/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 522, in run_setup
          super().run_setup(setup_script=setup_script)
        File "/tmp/pip-build-env-k5ezeotm/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 320, in run_setup
          exec(code, locals())
        File "<string>", line 21, in <module>
      ModuleNotFoundError: No module named 'torch'
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× Getting requirements to build wheel did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

Output of pip list:

$ pip list
Package                  Version
------------------------ ----------
filelock                 3.16.1
fsspec                   2024.12.0
Jinja2                   3.1.5
MarkupSafe               3.0.2
mpmath                   1.3.0
networkx                 3.4.2
nvidia-cublas-cu12       12.4.5.8
nvidia-cuda-cupti-cu12   12.4.127
nvidia-cuda-nvrtc-cu12   12.4.127
nvidia-cuda-runtime-cu12 12.4.127
nvidia-cudnn-cu12        9.1.0.70
nvidia-cufft-cu12        11.2.1.3
nvidia-curand-cu12       10.3.5.147
nvidia-cusolver-cu12     11.6.1.9
nvidia-cusparse-cu12     12.3.1.170
nvidia-nccl-cu12         2.21.5
nvidia-nvjitlink-cu12    12.4.127
nvidia-nvtx-cu12         12.4.127
pip                      24.3.1
setuptools               65.5.0
sympy                    1.13.1
torch                    2.5.1
triton                   3.1.0
typing_extensions        4.12.2

[LoicPZ]

Try :
pip install psutil
pip install flash_attn --no-build-isolation

[ytxmobile98]

Thanks!