Hey! Many thanks for the quick reply 
Pleased about the deepcopy.
So the model.to syntax…
I was under the impression this didn’t move the model, just changed its formatting as the documentation here (https://pytorch.org/tutorials/beginner/saving_loading_models.html 125) suggests:
“converts the initialized  model  to a CUDA optimized model using  model.to(torch.device('cuda')) .”
It sounds like the map_location bit in torch.load(PATH, map_location=device) specifies where the model is?