Hi William -- we have absolutely not copied any of Lightning's APIs.

In fact, our PyTorch API makes some significantly different design choices than Lightning does -- e.g., we require users to step optimizers and run the backward pass explicitly, which is a bit lower-level but allows for more flexibility when using the API.

For instance, here is an example of a GAN using our PyTorch API: https://github.com/determined-ai/determined/blob/master/exam...

This is a port of this PyTorch Lightning example: https://github.com/PyTorchLightning/pytorch-lightning/blob/m...

Despite the former being a port of the latter, there are significant differences between the two APIs.

More broadly, we welcome competition in this space and think there's a lot that we can all learn from one another.