Beta parameter is ignored in GPVAE when using the IWAE setting

[AlexandreAbraham]

Issue description

In the backbone of GPVAE, a different path is taken depending on whether IWAE is used or not.

In the case K=1, the elbo is updated like this:

elbo = -nll - self.beta * kl

In the case K>1, the elbo is updated like that:

elbo = -nll - kl

I understand that those usages are different, but it feels wrong to me to silently ignore a parameter. Also, I do not see why beta could not be applied in the IWAE case. I therefore suggest one of:

• Raise a warning if K is set >1 and Beta is specified by the user to avoid misunderstanding
• Change the IWAE loss to be computer as the beta-VAE one.

Let me know so I can propose a PR.

Thanks for the great software!

[github-actions]

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[github-actions]

This issue had no activity for 14 days. It will be closed in 1 week unless there is some new activity. Is this issue already resolved?

[AlexandreAbraham]

Still not resolved AFAIK

[AugustJW]

Hi Alexander,

Apologies for the delayed response, and thank you very much for pointing this out!

At this stage, we would like to stay consistent with the official GP-VAE implementation. Additionally, there doesn't appear to be any established foundation or implementation for combining beta with IWAE. Given this, we believe the most appropriate solution would be to raise a warning when K > 1 and beta is specified, as you suggested.

If you're interested in proceeding with a PR to implement this warning, we'd be happy to review it. Thanks again for your valuable contribution to improving the software!

[AlexandreAbraham]

No problem, it's a very minor issue, I understand that it's not a priority ;).
I'll push a PR soon.