L4 Latent Variable Models and Variational AutoEncoders -- CS294-158 SP24 Deep Unsupervised Learning

[@kamilkisielewicz2910]

Great lecture, was nice to have the derivation of the objective spelled out in such an intuitive way

[@sd-ti4yv]

Very useful lectures. Thank you.

[@KostyaKanishev]

To the question 21:05 The estimate is unbiased - it is correctly stated that it is asymptotically exact - but it has high variance. The variational inference approach gives another tradeoff: lower the variance at the cost of the bias introduced by restricting the family of the proposal latent densities q(z).

[@sahhaf1234]

@40:13 yes, but how to backpropagate through such a thing? That's not clear at all.. It is all the more difficult to understand because the neural nets hide within pdf's...

[@GobalKrishnanV]

What kind of book to read, please refer the book from start. give document for it.

[@spartacusche]

Which probability course to revise to understadn qickli all this? sampling ...(from youtube) or other

[@toyeoloko]

Is the code for the examples available or is it possible to get?

[@spartacusche]

on github you can find course 2020 with demos and solutions

[@mingzhou2213]

At time 1:15:22 (slide 55) for likelihood ratio gradient on VAE, I did my calculation. And for the first term (the one that does not become 0 eventually), I have the term sum over all z, we start with the term 1/q * \triangledown_\phi (q * [ .... ] ) = 1/q * \triangledown_\phi (q * [.... ]) + 1/q * q * \triangledown_\phi [...], I see the expected value of the second term is 0. For the first term, when i take expectation, it becomes \sum_z q * 1/q \triangledown_\phi (q* [....]) = \sum_z \triangledown_\phi (q* [...]) not sure how to proceed... and it's not the same case as slide 56 because we don't have something of q_phi(z|x) f(z), in this case we have q_phi(z|x) [ logp_z(z) + log p_\theta(z|x) - log q_phi(z|x) ]

[@MSalman1]

Just goes to show how much of stats and probability is required here.... I mean I did not know what "Importance sampling" was.. Great lecture though!

[@spartacusche]

what does he mean by I sample z, minute 23?

[@rabbithole9853]

I guess because I am a person below the average, I feel the lecture is very difficult to follow. Thanks for sharing though.