[Python] PyTorch installed via uv project shows CPU-only version on Windows with CUDA...

I'm trying to set up a Python project using uv and pyproject.toml on Windows. I want to install the CUDA-enabled PyTorch, but after installing, when I check the version, it shows CPU-only.

Here’s my pyproject.toml setup:

[project]
name = "transformerpractice"
version = "0.1.0"
description = "Add your description here"
readme = "README.md"
requires-python = ">=3.10"
dependencies = [
"en-core-web-sm",
"ko-core-news-sm",
"openpyxl>=3.1.5",
"pandas>=2.3.3",
"spacy>=3.8.8",
"torchtext==0.16.0",
"torch==2.1.0",
]

[tool.uv.sources]
en-core-web-sm = { url = "https://github.com/explosion/spacy-models/releases/download/en_core_web_sm-3.8.0/en_core_web_sm-3.8.0.tar.gz" }
ko-core-news-sm = { path = "tokenizer/ko_core_news_sm-3.8.0-py3-none-any.whl" }
torch = [
{ index = "pytorch-cu121", marker = "sys_platform == 'win_amd64'" },
]

[[tool.uv.index]]
name = "pytorch-cu121"
url = "https://download.pytorch.org/whl/cu121"
explicit = false


After installing, I run:

import torch

print(torch.__version__)
print(torch.version.cuda)


And the output is:

2.1.0+cpu
None


It seems like the CPU version is installed, not the CUDA version.

What I tried:

1. 
   Specifying the PyTorch version with torch==2.1.0 in [project.dependencies].
   
   
2. 
   Adding a custom PyTorch index with CUDA support using [tool.uv.index].
   
   
3. 
   Checking that I'm on Windows 64-bit (sys_platform == 'win_amd64').
   

Question:

How can I configure pyproject.toml with uv so that it installs the CUDA-enabled PyTorch (2.1.0+cu121) on Windows?

Any guidance on how uv handles extra indices and platform markers for PyTorch would be helpful.

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