variable (note the leading colon symbol)
     "CUBLAS_WORKSPACE_CONFIG=:16:8" or
     "CUBLAS_WORKSPACE_CONFIG=:4096:2".See the cuDNN 8 Release Notes
     for more information.
Note:
 If the following conditions are satisfied: 1) cudnn is enabled,
 2) input data is on the GPU 3) input data has dtype
 "torch.float16" 4) V100 GPU is used, 5) input data is not in
 "PackedSequence" format persistent algorithm can be selected to
 improve performance.

Examples:
  >>> rnn = nn.RNN(10, 20, 2)
  >>> input = torch.randn(5, 3, 10)
  >>> h0 = torch.randn(2, 3, 20)
  >>> output, hn = rnn(input, h0)
