I am using Ubuntu 16.04. The GPU indexing are the same as you have.
If you want to execute xxx.py 313 using only GPUs 0,1 in Ubuntu 16.04, use the following command as
CUDA_VISIBLE_DEVICES=2,3 python xxx.py

with nn.DadaParallel in xxx.py 313.
In addition, I don’t think that dataparallel accepts only one gpu.