March 2013 cosmomc: initial power spectrum parameters

Use of Cobaya. camb, CLASS, cosmomc, compilers, etc.
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Brent Follin
Posts: 7
Joined: April 11 2013
Affiliation: UC Davis

March 2013 cosmomc: initial power spectrum parameters

Post by Brent Follin » April 14 2013

I was wondering if someone could help me understand the primordial power parameters in the March 2013 version of cosmomc. I see how to do it for the other parameters, but the primordial parameters seem to be handled differently. I see they're passed together as an array (InitPower) in cmbtypes.f90 below:

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Type, extends(TTheoryParams) :: CMBParams
        real(mcp) InitPower(max_inipower_params)
        !These are fast paramters for the initial power spectrum
        !Now remaining (non-independent) parameters
However, I don't see where cosmomc is told which element of that array is which cosmological parameter. For instance, where is cosmomc told that InitPower(i) is nrun?

Specifically, I want to parameterize some features in the primordial power, but I can't figure out how to (1) figure out which parameter in the .ini file corresponds to which element of InitPower, or (2) how to pass additional elements of InitPower to camb. Any help would be appreciated!

Antony Lewis
Posts: 1941
Joined: September 23 2004
Affiliation: University of Sussex
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Re: March 2013 cosmomc: initial power spectrum parameters

Post by Antony Lewis » April 15 2013

The paramterization code calls

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SetTheoryParameterNumbers(slow_num, semi_slow_num)
where the second parameter determines the number of initial power parameters. The .paramnames file gives the parameter names, and the actual meaning in CAMB is set in CMB_Cls_simple.f90's SetCAMBInitPower.

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