Adding multi-source plane lens functionality

[aangress]

@aymgal

Still very much a WiP! Attempting to add the plotting functionality for double (and multi) source plane lenses. This hopefully shouldn't be a giant overhaul of the model plotting, just something extra.

[aangress]

My plans for changes:

• Allow composable lens model to hold a list of composable mass and light models
• Evaluate nested multi-lens equation after sorting objects by redshift
• Will need beta parameter (scaling/angular diameter distance ratio) to evaluate equation. Can retrieve beta in two ways:

1. If beta was a free parameter during lens modeling, get beta from associated chains file. This will require user to include a list of beta variable names in JSON file to check for in chains file
2. If beta was not a free parameter, use redshifts/Astropy to calculate angular diameter distances and betas from there

[aymgal]

Hi @aangress! That looks very good! I think however that this will be easier to finalise after I push my changes regarding the support of pixelated mass profiles and lens light profiles... Since it is touching the composable models part of it.

Sorry for the lack of quick answers, I am still very busy outside science these days. I hope to be able to work again and hopefully finalise my changes next week, but will let you know if not.

[aangress]

Happy New Year @aymgal! I just wanted to check in to see how your implementation for the pixelated profiles is going. No rush to push anything!

[aymgal]

Hi @aangress, thanks to come and ask about progress. Unfortunately I'm still not having enough free time between my two contracts to work on it (as I initially hoped) 😕 So nothing new, sorry for these delay. Are these critically blocking you for important goals? If so, I can try working on this soon, hopefully.

[aymgal]

Hi @aangress , I just merged #76 which in particular adds lens light model supports, and reorganizes a few bits of the ComposableModel classes. Hopefully first updating your branch to these latest changes would make it easier for you to add multi-plane support. Please let me know if you get any trouble in the process, and/or if you have request changes.