title: How to use Pytorch to assign multi gpu without cuda_visible_device
body: <p>I use docker in a server, the GPU is randomly assigned to me, and <code>cuda_visible_device</code> is forbidden in pbs or shell document because it will conflict with server's assignment.</p>
  
  <p>How can I replace <code>os.environ(cuda_visible_device)</code> safely?<br>
  Please give me an example</p>