UV PyTorch indexes not found for cu126

[bakas-george]

Summary

Hello,

By default, torch installation via uv using CUDA 12.6 fails due to missing support in the default uv PyTorch indexes:

• The uv PyTorch index does not support CUDA 12.6 yet whereas CUDA 12.4 is officially supported on uv.

The issue is that you can manually override the index url on the command line:

uv pip install torch --index-url https://download.pytorch.org/whl/cu126

but when specified in the pyproject.toml this is not overridden.

Platform

Linux Ubuntu 24.04 LTS

Version

uv 0.6.13

Python version

3.13.3

[charliermarsh]

Sorry, what do you mean by “by default”? How would uv know to look on the PyTorch index if it wasn’t specified?

[bakas-george]

It was specified in the pyproject.toml like this:

[[tool.uv.index]]
name = "torch-gpu"
url = "https://download.pytorch.org/whl/cu126"
explicit = true

[charliermarsh]

Okay, but what error are you experiencing when you do that? uv doesn't hard-code any distinction between those indexes. All PyTorch indexes should work equally well.

[rulller]

When running uv sync it does not install some additional libraries needed for pytorch with cuda.

On the other hand, when running uv pip install torch --index https://download.pytorch.org/whl/cu126 the libraries are installed.

These libraries are:

 + nvidia-cublas-cu12==12.6.4.1
 + nvidia-cuda-cupti-cu12==12.6.80
 + nvidia-cuda-nvrtc-cu12==12.6.77
 + nvidia-cuda-runtime-cu12==12.6.77
 + nvidia-cudnn-cu12==9.5.1.17
 + nvidia-cufft-cu12==11.3.0.4
 + nvidia-curand-cu12==10.3.7.77
 + nvidia-cusolver-cu12==11.7.1.2
 + nvidia-cusparse-cu12==12.5.4.2
 + nvidia-cusparselt-cu12==0.6.3
 + nvidia-nccl-cu12==2.21.5
 + nvidia-nvjitlink-cu12==12.6.85
 + nvidia-nvtx-cu12==12.6.77
 + triton==3.2.0

[konstin]

Can you share your pyproject.toml?

If you are using explicit = true, it will work different than --index https://download.pytorch.org/whl/cu126, does it work without explicit = true?

[KukumavMozolo]

Thats a known bug wiith pytorch 2.6.0 and cu126, use cu124
python-poetry/poetry#10152
pytorch/pytorch#146679 (comment)
also allready mentioned here i think: #10693