U consider it a machine bug or sys bug or code bug?
I’m using ubuntu 16.04 with cuda9.0 and cudnn7.0.5, pytorch 1.0
As mentioned before ,the os env is able to make my code see the gpu and exclude others.and then ,I can use .cuda() or  to() to transfer data on valid gpus and run it.Is this situation i described right?Cuz I don’t know where to debug, I need to confirm such process correctness.