xref: /aosp_15_r20/external/pytorch/torch/mtia/_utils.py (revision da0073e96a02ea20f0ac840b70461e3646d07c45)
1from typing import Any
2
3import torch
4
5# The _get_device_index has been moved to torch.utils._get_device_index
6from torch._utils import _get_device_index as _torch_get_device_index
7
8
9def _get_device_index(
10    device: Any, optional: bool = False, allow_cpu: bool = False
11) -> int:
12    r"""Get the device index from :attr:`device`, which can be a torch.device object, a Python integer, or ``None``.
13
14    If :attr:`device` is a torch.device object, returns the device index if it
15    is a MTIA device. Note that for a MTIA device without a specified index,
16    i.e., ``torch.device('mtia')``, this will return the current default MTIA
17    device if :attr:`optional` is ``True``. If :attr:`allow_cpu` is ``True``,
18    CPU devices will be accepted and ``-1`` will be returned in this case.
19
20    If :attr:`device` is a Python integer, it is returned as is.
21
22    If :attr:`device` is ``None``, this will return the current default MTIA
23    device if :attr:`optional` is ``True``.
24    """
25    if isinstance(device, int):
26        return device
27    if isinstance(device, str):
28        device = torch.device(device)
29    if isinstance(device, torch.device):
30        if allow_cpu:
31            if device.type not in ["mtia", "cpu"]:
32                raise ValueError(f"Expected a mtia or cpu device, but got: {device}")
33        elif device.type != "mtia":
34            raise ValueError(f"Expected a mtia device, but got: {device}")
35    if not torch.jit.is_scripting():
36        if isinstance(device, torch.mtia.device):
37            return device.idx
38    return _torch_get_device_index(device, optional, allow_cpu)
39