generate translation using multiple GPUs?

[xwuShirley]

Dear Author @SunbowLiu ,

I saw your issue regarding to multiple-GPUs generation.
facebookresearch/fairseq#1937

I wonder if your released code here actually do multiple GPU generation here. Or you only put the 1GPU code?
If your code indeed can do multiple GPU, could you give an example here?

Thank you very much for the help.
Best,
Shirley