Hi,
To use cuda, you should create your model as usual then call model.cuda() to send all parameters of this model (and other stuff in the model) to the gpu. Then you need to make sure that your inputs are on the gpu as well input = input.cuda(). Then you can forward on the gpu by doing: model(input).
Note that model.cuda() will change the model inplace while input.cuda() will not change input inplace and you need to do input = input.cuda().