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BellaNasirudin / py21cmmc_fg

A foreground and instrumental plugin for py21cmmc
MIT License
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variance of power #8

Closed steven-murray closed 5 years ago

steven-murray commented 6 years ago

We need to calculate the variance (or perhaps covariance) of the power along with the power itself, to be used in weighting.

steven-murray commented 6 years ago

I have added the basic machinery to do this into powerbox (>=v0.5.2), and as of 03f80d67c6840e4e6a2b40d2719b5a01b68981e9, this is calculated when averaging the power. Nevertheless, I am not convinced that this will work okay. My initial tests on a non-foreground box indicate that the estimate of the variance is way off. It may be more useful to use an analytic covariance model.

BellaNasirudin commented 6 years ago

Do I still need to find the covariance of the foregrounds?

steven-murray commented 6 years ago

We definitely need the covariance, but I'm not sure of the best way of doing it -- whether by numerically finding it from simulation, or by analytically computing it. I was hoping the former would be good enough, but it might not be.