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exoplanet-dev / exoplanet

Fast & scalable MCMC for all your exoplanet needs!
https://docs.exoplanet.codes
MIT License
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Including Relativistic effects in exoplanet? #54

Closed ericagol closed 3 years ago

ericagol commented 5 years ago

The new Sgr A*/S02 paper on GR effects made me wonder if it would be worthwhile to include relativistic effects in exoplanet:

https://science.sciencemag.org/content/early/2019/07/24/science.aav8137

It's also interesting to note that they used the STAN implementation of NUTS as a check on their results.

arjunsavel commented 4 years ago

Hello! I was wondering if it'd be desirable to implement this by introducing post-Newtonian corrections with REBOUNDx (example here).

dfm commented 4 years ago

@arjunsavel That would definitely be interesting! I've implemented an interface to rebound (without the x) and an extension to include this would be cool, but I don't have a sense of how feasible that would be (does REBOUNDx play nice with variations for example?). Either way, if you're interested in taking a stab at it, that would be awesome! Take a look here for the custom Theano op that does the N-body integration and propagates derivatives using Python (there's also a faster version that uses the C-API directly, but it's probably better to start with Python) and here for where that gets a more "user-friendly" orbit interface. It's not super well commented, but I'm happy to chat if you're interested.

arjunsavel commented 4 years ago

@dfm Thanks for the response! I'd been thinking of making a PR to rebound-pymc3, but I agree that starting with the Python implementation would make sense. Also, I'm not sure whether REBOUNDx handles variations — I'll definitely give it a go, though!

dfm commented 3 years ago

Closed by #133