text: # Copyright The PyTorch Lightning team.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  import torch
  
  from pytorch_lightning.utilities.exceptions import MisconfigurationException
  
  
  def pick_multiple_gpus(nb):
      '''
      Raises:
          MisconfigurationException:
              If ``gpus`` is set to 0, when ``auto_select_gpus=True``.
      '''
      if nb == 0:
          raise MisconfigurationException(
              r"auto_select_gpus=True, gpus=0 is not a valid configuration.\
              Please select a valid number of GPU resources when using auto_select_gpus."
          )
  
      nb = torch.cuda.device_count() if nb == -1 else nb
  
      picked = []
      for _ in range(nb):
          picked.append(pick_single_gpu(exclude_gpus=picked))
  
      return picked
  
  
  def pick_single_gpu(exclude_gpus: list):
      '''
      Raises:
          RuntimeError:
              If you try to allocate a GPU, when no GPUs are available.
      '''
      for i in range(torch.cuda.device_count()):
          if i in exclude_gpus:
              continue
          # Try to allocate on device:
          device = torch.device(f"cuda:{i}")
          try:
              torch.ones(1).to(device)
          except RuntimeError:
              continue
          return i
      raise RuntimeError("No GPUs available.")
  