fix for "OMP: Error #15: Initializing libiomp5md.dll, but found libiomp5md.dll already initialized" with CUDA enabled

[gessyoo]

I found that I could enable CUDA support by installing the pytorch version for RTX 3.x, but the code threw an error about OMP: Error #15. The hacky workaround I found was adding:

`os.environ['KMP_DUPLICATE_LIB_OK']='True'

after line 9: 　import os

in main_test.py

with that small change, and pytorch with CUDA support, CUDA works　

You almost certainly have a better solution than what I found, but I thought I'd pass along it anyway, for what it's worth.