[CAMB/CosmoMC] Reusing generated Cls in CosmoMC

Use of Healpix, camb, CLASS, cosmomc, compilers, etc.
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Luke Hart
Posts: 42
Joined: July 13 2015
Affiliation: University of Manchester

[CAMB/CosmoMC] Reusing generated Cls in CosmoMC

Post by Luke Hart » June 11 2018

Within CAMB, the CMB power spectrum is generated and outputted to file. Similarly, the CMB power spectra are communicated to CosmoMC when used in conjunction with a likelihood. Is there a way to import Cls to bypass the whole CAMB calculation step when trying to deduce the likelihood for a given set of theory Cls?

Antony Lewis
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Joined: September 23 2004
Affiliation: University of Sussex
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Re: [CAMB/CosmoMC] Reusing generated Cls in CosmoMC

Post by Antony Lewis » June 12 2018

If you've run a chain and produced .data files, you can importance sample quickly by reading cls from the data files. But there's no specific built-in function to read cls from any other external file.

Luke Hart
Posts: 42
Joined: July 13 2015
Affiliation: University of Manchester

[CAMB/CosmoMC] Reusing generated Cls in CosmoMC

Post by Luke Hart » June 12 2018

I appreciate you Antony and others are quite busy, but would you have any idea how one would go about this?? I have had a look at the GeneralSetup.F90 file as well as the driver file, the CosmoTheory.f90 file etc. and I know it will probably be just a small co-ordination of the parameter references to the file read options, so I'm sort of at a loss.

If we get this working, I have some other code that if refined, could be a nice addition to the standard CosmoMC code.

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