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dfm / ketu

I can haz planetz?
MIT License
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Exoplanet Fits Have Phase Transitions #1

Closed eggplantbren closed 11 years ago

eggplantbren commented 11 years ago

As seen by Fengji, multi-planet fits, at least to RV data, have phase transitions. You'd better hope you can initialise above them. If not you may never find the good fits.

davidwhogg commented 11 years ago

define "phase transition"

eggplantbren commented 11 years ago

It's the spike/slab situation. If the posterior has that shape then you can't move between the spike and the slab, even though it's unimodal. I don't have an intuition for when they occur in data analysis problems. They do tend to be uncommon, but anecdotally I've seen them the most in fitting sinusoidal-type models to time series data.

On Thu, Jan 24, 2013 at 3:53 PM, David W. Hogg notifications@github.comwrote:

define "phase transition"

— Reply to this email directly or view it on GitHubhttps://github.com/dfm/turnstile/issues/1#issuecomment-12634690.

Dr Brendon J. Brewer Department of Statistics, The University of Auckland, New Zealand Ph: +64 27 500 1336 Web: http://stat.auckland.ac.nz/~brewer/

davidwhogg commented 11 years ago

I think this is an issue for exoplanets, not for the code. Closing