Why do we print just half of `trainable_params" when using 4-bits?

[HanGuo97]

Hi, first of all, thanks for this amazing repo!

I have a quick (and very likely dumb) question about the following line. Specifically, why do we print just half of the variable when bits==4? https://github.com/artidoro/qlora/blob/7f4e95a68dc076bea9b3a413d2b512eca6d004e5/qlora.py#L418

Thanks in advance for your time!