Question on the theory mean calculation

LSSTDESC / tomo_challenge

2020 Tomographic binning challenge

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Question on the theory mean calculation #5

Closed EiffL closed 4 years ago

EiffL commented 4 years ago

So, I'm puzzled by this line:

https://github.com/LSSTDESC/tomo_challenge/blob/c89d57eb195c5dcdd1e54294678549590e4af86a/tomo_challenge/metrics.py#L212

Shouldn't it be C_obs instead i.e. including the noise power spectrum in auto-spectra? or am I missing something?

For the initial metric of S/N I wasn't too sure, but for the FoM, I would have definitely included the noise.

joezuntz commented 4 years ago

No, this is correct, because we would compare to a noise-subtracted estimate of the observed signal in any parameter estimation. It doesn't actually matter either way here, though, because for Fisher we don't use the mean. And for the SNR metric it would add a constant offset to all the results I think.

EiffL commented 4 years ago

Great thanks for the clarification :-) I hadn't thought the data vector would come in noise subtracted. that answers it.