non intuitive batch_size in ddp
Is there a way in PyTorchLightning to set your desired batch size, say 512 and then have the effective batch size per processor (which is normally batch_size*num_gpus) be computed automatically?  Right now your effective batch size scales with the number of gpus so these calculations must be computed outside of pytorchlightning (as far as my tests have shown)...  This seems like something that PL could/should be able to handle.  You'd likely also have to set a maximum processor batch_size so that it could determine an accumulate_grad_batches so as not to use too much memory.