CosmoMC : non-uniform prior
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- Posts: 17
- Joined: February 11 2014
- Affiliation: IRAP Toulouse
CosmoMC : non-uniform prior
Hello all,
I would like to use a non-uniform prior for one existing cosmological parameter in cosmomc, namely "ns". Let's say that I would like a uniform prior for "ns^2" : what would be the best way to proceed?
Thanks a lot in advance.
Best regards.
I would like to use a non-uniform prior for one existing cosmological parameter in cosmomc, namely "ns". Let's say that I would like a uniform prior for "ns^2" : what would be the best way to proceed?
Thanks a lot in advance.
Best regards.
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- Posts: 1941
- Joined: September 23 2004
- Affiliation: University of Sussex
- Contact:
Re: CosmoMC : non-uniform prior
Probably easiest to add it as a "non-base prior" in the function TP_NonBaseParameterPriors of CosmologyParameterizations.f90, like the Hubble parameter one.
Alternative you could modify the parameterization so that the MCMC parameter is ns^2 rather than ns.
Alternative you could modify the parameterization so that the MCMC parameter is ns^2 rather than ns.
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- Posts: 17
- Joined: February 11 2014
- Affiliation: IRAP Toulouse
CosmoMC : non-uniform prior
Thanks for your answer Antony ; for the second solution that you propose, do I also have to modify something in CosmologyParameterizations.f90 ? I understand that ns corresponds to the first element of the InitPower array, right ? Should I modify it in the SetFast routine maybe?
Thanks again!
Thanks again!
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- Posts: 1941
- Joined: September 23 2004
- Affiliation: University of Sussex
- Contact:
Re: CosmoMC : non-uniform prior
Yes, and probably use a new .paramnames file with a name for your new parameter (and maybe add a new derived parameter with the now-derived ns if you want).
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- Posts: 17
- Joined: February 11 2014
- Affiliation: IRAP Toulouse
CosmoMC : non-uniform prior
Thanks again Antony !
A small correction to my previous message though : "ns" is the second element of the InitPower array.
A small correction to my previous message though : "ns" is the second element of the InitPower array.