Description

There a some use-cases (at least I have one), where some also needs the ladj,
while calculating the inverse operation. For my use-case I am not only using the normalizing flow
to generate samples, but also want to know the likelihood of the produced samples.

Implementation

Implementation could be somewhat hard, because in principle every transformation would need to include another
method inverse_and_ladj. I am willing to help and contribute pull requests for that. My main focus at the moment are neural spline flows.

I'm mainly opening this issue to figure out if this is wanted, and one has to decide how to introduce the functionality in the consuming classes of the transformations.