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22 votes
4 answers
8k views

Likelihood-free inference - what does it mean?

Recently I have become aware of 'likelihood-free' methods being bandied about in literature. However I am not clear on what it means for an inference or optimization method to be likelihood-free. In ...
piccolo's user avatar
  • 967
16 votes
1 answer
18k views

Variational Autoencoder − Dimension of the latent space

I've done some experiments to understand the influence of the dimension of the latent space in a VAE, and it seems that the higher the space, the harder it is to generate realistic images. I might ...
Arthur Pesah's user avatar
13 votes
3 answers
19k views

Why use Binary Cross Entropy for Generator in Adversarial Networks

I'm trying to work with General Adversarial Networks and there's something I'm seeing everywhere but can't explain why... the GANs are usually constructed from a Generator (which usually generates an ...
Cypher's user avatar
  • 515
3 votes
2 answers
897 views

How is the variance for a diffusion kernel derived for a diffusion model?

So I'm watching this video tutorial from CVPR this year on diffusion models, and I am confused by the variance term in the distribution on the left on the video. I understand that in the forward ...
Cynthia Kim's user avatar
22 votes
1 answer
6k views

Why in Variational Auto Encoder (Gaussian variational family) we model $\log\sigma^2$ and not $\sigma^2$ (or $\sigma$) itself?

In theory the encoder in VAE (assuming that variational family is Gaussian) generates the $\mu$ and $\sigma$ (or $\sigma^2$). But, in practice, I have seen people assuming the output is $\log\sigma^2$....
user3639557's user avatar
  • 1,502
14 votes
3 answers
3k views

Is the optimization of the Gaussian VAE well-posed?

In a Variational Autoencoder (VAE), given some data $x$ and latent variables $t$ with prior distribution $p(t) = \mathcal{N}(t \mid 0, I)$, the encoder aims to learn a distribution $q_{\phi}(t)$ that ...
learner's user avatar
  • 707
4 votes
1 answer
1k views

Generative Adversial Networks: how the generator is trained with the output of discriminator

Recently I have learned about Generative Adversarial Networks. For training the Generator, I am somehow confused how it learns. Here is an implemenation of GANs: ...
Kadaj13's user avatar
  • 395
1 vote
0 answers
2k views

GAN losses balance, but quality of generated image still bad

I build a GAN to train on the fashion mnist dataset. To facilitate the training, I have added gaussian noise with mean 0 and stddev 0.15 on the images. My generator is a 2 layer MLP with sigmoid ...
Chester Cheng's user avatar