I don’t exactly understand what you mean…
From what I understand, if you want to use a pretrained model to test it (no more learning), you can use the model.state_dict() to load the ‘best’ weights. If you want to continue training you need both, the model.state_dict() and the optimizer.state_dict().
My problem applies to the second use case, where I want to continue training but my model is slightly different. So I am not sure whether I still need the optimizer.state_dict() and if so, how I can apply it to a new model.