uv/docs/guides/integration/pytorch.md
Maxime ec997b6fd2
Update PyTorch/Python version tip (#12402)
PyTorch 2.6.0 supports Python 3.13, and publishes wheels for it. Update
the tip to reflect this.


## Summary

Clarify docs.

## Test Plan

Look for "cp313" at the following URLs:
- [x] https://download.pytorch.org/whl/cu124/torch/
- [x] https://download.pytorch.org/whl/torch/
2025-03-23 17:23:08 -04:00

422 lines
12 KiB
Markdown

---
title: Using uv with PyTorch
description:
A guide to using uv with PyTorch, including installing PyTorch, configuring per-platform and
per-accelerator builds, and more.
---
# Using uv with PyTorch
The [PyTorch](https://pytorch.org/) ecosystem is a popular choice for deep learning research and
development. You can use uv to manage PyTorch projects and PyTorch dependencies across different
Python versions and environments, even controlling for the choice of accelerator (e.g., CPU-only vs.
CUDA).
!!! note
Some of the features outlined in this guide require uv version 0.5.3 or later. We recommend upgrading prior to configuring PyTorch.
## Installing PyTorch
From a packaging perspective, PyTorch has a few uncommon characteristics:
- Many PyTorch wheels are hosted on a dedicated index, rather than the Python Package Index (PyPI).
As such, installing PyTorch often requires configuring a project to use the PyTorch index.
- PyTorch produces distinct builds for each accelerator (e.g., CPU-only, CUDA). Since there's no
standardized mechanism for specifying these accelerators when publishing or installing, PyTorch
encodes them in the local version specifier. As such, PyTorch versions will often look like
`2.5.1+cpu`, `2.5.1+cu121`, etc.
- Builds for different accelerators are published to different indexes. For example, the `+cpu`
builds are published on https://download.pytorch.org/whl/cpu, while the `+cu121` builds are
published on https://download.pytorch.org/whl/cu121.
As such, the necessary packaging configuration will vary depending on both the platforms you need to
support and the accelerators you want to enable.
To start, consider the following (default) configuration, which would be generated by running
`uv init --python 3.12` followed by `uv add torch torchvision`.
In this case, PyTorch would be installed from PyPI, which hosts CPU-only wheels for Windows and
macOS, and GPU-accelerated wheels on Linux (targeting CUDA 12.4):
```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12"
dependencies = [
"torch>=2.6.0",
"torchvision>=0.21.0",
]
```
!!! tip "Supported Python versions"
At time of writing, PyTorch does not yet publish wheels for Python 3.14; as such projects with
`requires-python = ">=3.14"` may fail to resolve. See the
[compatibility matrix](https://github.com/pytorch/pytorch/blob/main/RELEASE.md#release-compatibility-matrix).
This is a valid configuration for projects that want to use CPU builds on Windows and macOS, and
CUDA-enabled builds on Linux. However, if you need to support different platforms or accelerators,
you'll need to configure the project accordingly.
## Using a PyTorch index
In some cases, you may want to use a specific PyTorch variant across all platforms. For example, you
may want to use the CPU-only builds on Linux too.
In such cases, the first step is to add the relevant PyTorch index to your `pyproject.toml`:
=== "CPU-only"
```toml
[[tool.uv.index]]
name = "pytorch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true
```
=== "CUDA 11.8"
```toml
[[tool.uv.index]]
name = "pytorch-cu118"
url = "https://download.pytorch.org/whl/cu118"
explicit = true
```
=== "CUDA 12.1"
```toml
[[tool.uv.index]]
name = "pytorch-cu121"
url = "https://download.pytorch.org/whl/cu121"
explicit = true
```
=== "CUDA 12.4"
```toml
[[tool.uv.index]]
name = "pytorch-cu124"
url = "https://download.pytorch.org/whl/cu124"
explicit = true
```
=== "ROCm6"
```toml
[[tool.uv.index]]
name = "pytorch-rocm"
url = "https://download.pytorch.org/whl/rocm6.2"
explicit = true
```
=== "Intel GPUs"
```toml
[[tool.uv.index]]
name = "pytorch-xpu"
url = "https://download.pytorch.org/whl/xpu"
explicit = true
```
We recommend the use of `explicit = true` to ensure that the index is _only_ used for `torch`,
`torchvision`, and other PyTorch-related packages, as opposed to generic dependencies like `jinja2`,
which should continue to be sourced from the default index (PyPI).
Next, update the `pyproject.toml` to point `torch` and `torchvision` to the desired index:
=== "CPU-only"
```toml
[tool.uv.sources]
torch = [
{ index = "pytorch-cpu" },
]
torchvision = [
{ index = "pytorch-cpu" },
]
```
=== "CUDA 11.8"
PyTorch doesn't publish CUDA builds for macOS. As such, we gate on `sys_platform` to instruct uv to use
the PyTorch index on Linux and Windows, but fall back to PyPI on macOS:
```toml
[tool.uv.sources]
torch = [
{ index = "pytorch-cu118", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
torchvision = [
{ index = "pytorch-cu118", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
```
=== "CUDA 12.1"
PyTorch doesn't publish CUDA builds for macOS. As such, we gate on `sys_platform` to instruct uv to limit
the PyTorch index to Linux and Windows, falling back to PyPI on macOS:
```toml
[tool.uv.sources]
torch = [
{ index = "pytorch-cu121", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
torchvision = [
{ index = "pytorch-cu121", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
```
=== "CUDA 12.4"
PyTorch doesn't publish CUDA builds for macOS. As such, we gate on `sys_platform` to instruct uv to limit
the PyTorch index to Linux and Windows, falling back to PyPI on macOS:
```toml
[tool.uv.sources]
torch = [
{ index = "pytorch-cu124", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
torchvision = [
{ index = "pytorch-cu124", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
```
=== "ROCm6"
PyTorch doesn't publish ROCm6 builds for macOS or Windows. As such, we gate on `sys_platform` to instruct uv
to limit the PyTorch index to Linux, falling back to PyPI on macOS and Windows:
```toml
[tool.uv.sources]
torch = [
{ index = "pytorch-rocm", marker = "sys_platform == 'linux'" },
]
torchvision = [
{ index = "pytorch-rocm", marker = "sys_platform == 'linux'" },
]
```
=== "Intel GPUs"
PyTorch doesn't publish Intel GPU builds for macOS. As such, we gate on `sys_platform` to instruct uv to limit
the PyTorch index to Linux and Windows, falling back to PyPI on macOS:
```toml
[tool.uv.sources]
torch = [
{ index = "pytorch-xpu", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
torchvision = [
{ index = "pytorch-xpu", marker = "sys_platform == 'linux' or sys_platform == 'win32'" },
]
# Intel GPU support relies on `pytorch-triton-xpu` on Linux, which should also be installed from the PyTorch index
# (and included in `project.dependencies`).
pytorch-triton-xpu = [
{ index = "pytorch-xpu", marker = "sys_platform == 'linux'" },
]
```
As a complete example, the following project would use PyTorch's CPU-only builds on all platforms:
```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12.0"
dependencies = [
"torch>=2.6.0",
"torchvision>=0.21.0",
]
[tool.uv.sources]
torch = [
{ index = "pytorch-cpu" },
]
torchvision = [
{ index = "pytorch-cpu" },
]
[[tool.uv.index]]
name = "pytorch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true
```
## Configuring accelerators with environment markers
In some cases, you may want to use CPU-only builds in one environment (e.g., macOS and Windows), and
CUDA-enabled builds in another (e.g., Linux).
With `tool.uv.sources`, you can use environment markers to specify the desired index for each
platform. For example, the following configuration would use PyTorch's CUDA-enabled builds on Linux,
and CPU-only builds on all other platforms (e.g., macOS and Windows):
```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12.0"
dependencies = [
"torch>=2.6.0",
"torchvision>=0.21.0",
]
[tool.uv.sources]
torch = [
{ index = "pytorch-cpu", marker = "sys_platform != 'linux'" },
{ index = "pytorch-cu124", marker = "sys_platform == 'linux'" },
]
torchvision = [
{ index = "pytorch-cpu", marker = "sys_platform != 'linux'" },
{ index = "pytorch-cu124", marker = "sys_platform == 'linux'" },
]
[[tool.uv.index]]
name = "pytorch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true
[[tool.uv.index]]
name = "pytorch-cu124"
url = "https://download.pytorch.org/whl/cu124"
explicit = true
```
Similarly, the following configuration would use PyTorch's Intel GPU builds on Windows and Linux,
and CPU-only builds on macOS (by way of falling back to PyPI):
```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12.0"
dependencies = [
"torch>=2.6.0",
"torchvision>=0.21.0",
"pytorch-triton-xpu>=3.2.0 ; sys_platform == 'linux'",
]
[tool.uv.sources]
torch = [
{ index = "pytorch-xpu", marker = "sys_platform == 'win32' or sys_platform == 'linux'" },
]
torchvision = [
{ index = "pytorch-xpu", marker = "sys_platform == 'win32' or sys_platform == 'linux'" },
]
pytorch-triton-xpu = [
{ index = "pytorch-xpu", marker = "sys_platform == 'linux'" },
]
[[tool.uv.index]]
name = "pytorch-xpu"
url = "https://download.pytorch.org/whl/xpu"
explicit = true
```
## Configuring accelerators with optional dependencies
In some cases, you may want to use CPU-only builds in some cases, but CUDA-enabled builds in others,
with the choice toggled by a user-provided extra (e.g., `uv sync --extra cpu` vs.
`uv sync --extra cu124`).
With `tool.uv.sources`, you can use extra markers to specify the desired index for each enabled
extra. For example, the following configuration would use PyTorch's CPU-only for
`uv sync --extra cpu` and CUDA-enabled builds for `uv sync --extra cu124`:
```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12.0"
dependencies = []
[project.optional-dependencies]
cpu = [
"torch>=2.6.0",
"torchvision>=0.21.0",
]
cu124 = [
"torch>=2.6.0",
"torchvision>=0.21.0",
]
[tool.uv]
conflicts = [
[
{ extra = "cpu" },
{ extra = "cu124" },
],
]
[tool.uv.sources]
torch = [
{ index = "pytorch-cpu", extra = "cpu" },
{ index = "pytorch-cu124", extra = "cu124" },
]
torchvision = [
{ index = "pytorch-cpu", extra = "cpu" },
{ index = "pytorch-cu124", extra = "cu124" },
]
[[tool.uv.index]]
name = "pytorch-cpu"
url = "https://download.pytorch.org/whl/cpu"
explicit = true
[[tool.uv.index]]
name = "pytorch-cu124"
url = "https://download.pytorch.org/whl/cu124"
explicit = true
```
!!! note
Since GPU-accelerated builds aren't available on macOS, the above configuration will fail to install
on macOS when the `cu124` extra is enabled.
## The `uv pip` interface
While the above examples are focused on uv's project interface (`uv lock`, `uv sync`, `uv run`,
etc.), PyTorch can also be installed via the `uv pip` interface.
PyTorch itself offers a [dedicated interface](https://pytorch.org/get-started/locally/) to determine
the appropriate pip command to run for a given target configuration. For example, you can install
stable, CPU-only PyTorch on Linux with:
```shell
$ pip3 install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cpu
```
To use the same workflow with uv, replace `pip3` with `uv pip`:
```shell
$ uv pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cpu
```
## Automatic backend selection
In [preview](../../reference/settings.md#preview), uv can automatically select the appropriate
PyTorch index at runtime by inspecting the system configuration via `--torch-backend=auto` (or
`UV_TORCH_BACKEND=auto`):
```shell
$ UV_TORCH_BACKEND=auto uv pip install torch
```
When enabled, uv will query for the installed CUDA driver version and use the most-compatible
PyTorch index for all relevant packages (e.g., `torch`, `torchvision`, etc.). If no such CUDA driver
is found, uv will fall back to the CPU-only index. uv will continue to respect existing index
configuration for any packages outside the PyTorch ecosystem.
To select a specific backend (e.g., `cu126`), set `--torch-backend=cu126` (or
`UV_TORCH_BACKEND=cu126`).
At present, `--torch-backend` is only available in the `uv pip` interface, and only supports
detection of CUDA drivers (as opposed to other accelerators like ROCm or Intel GPUs).
As `--torch-backend` is a preview feature, it should be considered experimental and is not governed
by uv's standard [versioning policy](../../reference/policies/versioning.md). `--torch-backend` may
change or be removed entirely in future versions of uv.