why no logdet computed for the actnorm in conv2d

openai / glow

Code for reproducing results in "Glow: Generative Flow with Invertible 1x1 Convolutions"

https://arxiv.org/abs/1807.03039

MIT License

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why no logdet computed for the actnorm in conv2d #74

Open weixsong opened 5 years ago

weixsong commented 5 years ago

https://github.com/openai/glow/blob/eaff2177693a5d84a1cf8ae19e8e0441715b82f8/tfops.py#L256

In this line of code, after conv2d, another actnorm is used. I'm not quite clear why logdet is not computed for this actnorm, this actnorm also changed the distribution volume.

bgroenks96 commented 4 years ago

The conv2d operations are not applied to the random variable directly. They are used by the affine coupling layer to parameterize the affine transformation on the random variable.