tingard / hierarchial-spiral-modelling-paper

Bayesian Hierarchial Modelling of Spiral Galaxy tightness
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Notes after first read #1

Closed CKrawczyk closed 4 years ago

CKrawczyk commented 4 years ago
tingard commented 4 years ago

Thanks Coleman, do you think a short section on HMC and Hierarchical modelling is needed in the introduction?

CKrawczyk commented 4 years ago

I don't think so, but I am also very familiar with the techniques. If you want to include a bit more background I would put that information in the modeling section rather than the introduction as you are talking more about the tools rather than the science.

CKrawczyk commented 4 years ago

For my second paper I saved that kind of overview for the appendix as it can easily disrupt the flow of the paper.

tingard commented 4 years ago

I feel like the model definition is incomplete. Make sure all equations in the output of pymc3 display(model) are in the paper (e.g. Lik ~ Normal(r, sigma_r))

Screenshot 2020-04-01 at 14 55 58

Not sure how to make this legible...

CKrawczyk commented 4 years ago

This would be something like:

c ~ Cauchy(\alpha=0, \beta=10)
\phi_{gal} ~ Uniform(0, 90)
\sigma_{gal} ~ InverseGamma(\alpha=2, \beta=20)
\sigma_{r, i} ~ InverseGamma(\alpha=2, \beta=0.5)
\phi_{arm, i} ~ TruncatedNormal(\mu=\phi_{gal}, \sigma=\sigma_{gal}, lower=0, upper=90)
Likelihood ~ \prod_{i=1}^{N} Normal(\mu=r(\phi_{arm, i}, c), \sigma=\sigma_{r, i})

Where N is the number of galaxies in the sample and r(\phi, c) is given by equation ###.

Note, if any of this is incorrect you can fix it, but this is how you can display a multi layer model. The _{i} indexing is the key to make the structure more clear. You can also write the hyper priors in their own block to help keep them separate from the rest of the model.

tingard commented 4 years ago

I think most of these have been addressed in the most recent commits!

tingard commented 4 years ago

Hopefully everything here has been addressed, I'm closing this issue