| import torch |
| import torch._six |
| |
| |
| def _get_device_index(device, optional=False): |
| r"""Gets the device index from :attr:`device`, which can be a torch.device |
| object, a Python integer, or ``None``. |
| |
| If :attr:`device` is a torch.device object, returns the device index if it |
| is a CUDA device. Note that for a CUDA device without a specified index, |
| i.e., ``torch.device('cuda')``, this will return the current default CUDA |
| device if :attr:`optional` is ``True``. |
| |
| If :attr:`device` is a Python integer, it is returned as is. |
| |
| If :attr:`device` is ``None``, this will return the current default CUDA |
| device if :attr:`optional` is ``True``. |
| """ |
| if isinstance(device, torch._six.string_classes): |
| device = torch.device(device) |
| if isinstance(device, torch.device): |
| dev_type = device.type |
| if device.type != 'cuda': |
| raise ValueError('Expected a cuda device, but got: {}'.format(device)) |
| device_idx = device.index |
| else: |
| device_idx = device |
| if device_idx is None: |
| if optional: |
| # default cuda device index |
| return torch.cuda.current_device() |
| else: |
| raise ValueError('Expected a cuda device with a specified index ' |
| 'or an integer, but got: '.format(device)) |
| return device_idx |
