Minimization problem with cobaya

Use of Cobaya. camb, CLASS, cosmomc, compilers, etc.
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Helena Garcia
Posts: 17
Joined: October 05 2021
Affiliation: UCI

Minimization problem with cobaya

Post by Helena Garcia » April 24 2022

I ran cobaya minimization module with some extensions of the LambdaCDM model (6+1 and 6+2 nested models). I obtained "worse" Chi-square values for the models with more free parameters, which is not mathematically consistent. I am using as initial points the ones from previous converged chains. Has someone had the same problem? What could it be?

Thank you in advance,

Helena

Antony Lewis
Posts: 1842
Joined: September 23 2004
Affiliation: University of Sussex
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Re: Minimization problem with cobaya

Post by Antony Lewis » April 25 2022

Maker sure you are using a covmat from the chain run - degeneracies can be very tight in some extended models

Helena Garcia
Posts: 17
Joined: October 05 2021
Affiliation: UCI

Re: Minimization problem with cobaya

Post by Helena Garcia » April 26 2022

Thank you for your reply! I am using the covmat from the chains and the results still not consistent. Is there any other option I can try to get the right result?

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