Pixi cannot install gpu version of pytorch

[jkbhagatio]

Checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pixi, using pixi --version.

Reproducible example

Given something like this in the pyproject.toml

[tool.pixi.pypi-dependencies]
torch = { version = "==2.5.1+cu121" }

I get this error message:

failed to resolve pypi dependencies
╰─▶ Because there is no version of torch==2.5.1+cu121 and you require torch==2.5.1+cu121, we can conclude that your requirements are unsatisfiable.

My current work around is to comment out torch gpu related packages in my toml, then activate the environment via conda and pip install them thereafter. This is a bit annoying, and also means I cannot have an accurate version of my pixi.lock reflecting pytorch

Issue description

N / A

Expected behavior

torch==2.5.1+cu121 should be properly installed

[SubMarineas]

I also have the same problem

[ruben-arts]

This works for me to get torch from pypi
pixi.toml

[project]
channels = ["conda-forge"]
name = "torch-py"
platforms = ["linux-64"]

# Pytorch requires an extra index
[pypi-options]
extra-index-urls = ["https://download.pytorch.org/whl/cu121"]

# Use a later libc version than the default
[system-requirements]
libc = "2.35"

[pypi-dependencies]
torch = { version = "==2.5.1+cu121" }

[dependencies]
python = ">=3.10, <3.13"
numpy = "*"

pyproject.toml

[project]
name = "torch-py"
dependencies = [
    "torch==2.5.1+cu121",
]
requires-python = ">=3.10, <3.13"

[tool.pixi]
project.channels = ["https://fast.prefix.dev/conda-forge"]
project.platforms = ["linux-64"]

# Pytorch requires an extra index
pypi-options.extra-index-urls = ["https://download.pytorch.org/whl/cu121"]

# Use a later libc version than the default
system-requirements.libc = "2.35"

# Install conda dependencies
dependencies = { numpy = ">=2.1, <3" }

❯ pixi run python -c "import torch; print(torch.cuda.is_available())"
True