How do I download flash-attn? I have followed the downloading steps completely.

[ranck626]

pip install flash-attn --no-build-isolation
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Collecting flash-attn
Using cached https://pypi.tuna.tsinghua.edu.cn/packages/cd/1e/21321670cd3c2f225026d9fd89272cae661529238850e79f48ccf2f9e4e3/flash_attn-2.6.3.tar.gz (2.6 MB)
Preparing metadata (setup.py) ... error
error: subprocess-exited-with-error

× python setup.py egg_info did not run successfully.
│ exit code: 1
╰─> [20 lines of output]
fatal: not a git repository (or any of the parent directories): .git
/tmp/pip-install-dkk1c7h9/flash-attn_19179385fe6e4ee28168a736e89ca14d/setup.py:95: UserWarning: flash_attn was requested, but nvcc was not found. Are you sure your environment has nvcc available? If you're installing within a container from https://hub.docker.com/r/pytorch/pytorch, only images whose names contain 'devel' will provide nvcc.
warnings.warn(
Traceback (most recent call last):
File "", line 2, in
File "", line 34, in
File "/tmp/pip-install-dkk1c7h9/flash-attn_19179385fe6e4ee28168a736e89ca14d/setup.py", line 179, in
CUDAExtension(
File "/data/miniconda3/envs/vary-toy/lib/python3.10/site-packages/torch/utils/cpp_extension.py", line 1076, in CUDAExtension
library_dirs += library_paths(cuda=True)
File "/data/miniconda3/envs/vary-toy/lib/python3.10/site-packages/torch/utils/cpp_extension.py", line 1207, in library_paths
if (not os.path.exists(_join_cuda_home(lib_dir)) and
File "/data/miniconda3/envs/vary-toy/lib/python3.10/site-packages/torch/utils/cpp_extension.py", line 2416, in _join_cuda_home
raise OSError('CUDA_HOME environment variable is not set. '
OSError: CUDA_HOME environment variable is not set. Please set it to your CUDA install root.

  torch.__version__  = 2.4.1+cu121
  
  
  [end of output]

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

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.