I tried exporting a model for PyTorch Lite to use it on mobile.
Before I just used
script = torch.jit.trace(model, dummy_input)
script.save("model.pt")

which resulted in a 46 MB file.
But with
script = torch.jit.trace(model, dummy_input)
script_opt = optimize_for_mobile(script)
script_opt._save_for_lite_interpreter("model.ptl")

I get a resulting size of 92 MB.
I discovered that optimize_for_mobile is the problem.
How does it make the export so much bigger?
Does it just optimize for speed not for size?