minimun \chi^2

Use of Healpix, camb, CLASS, cosmomc, compilers, etc.
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moslem zarei
Posts: 28
Joined: March 11 2008
Affiliation: Isfahan University of Technology
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minimun \\chi^2

Post by moslem zarei » September 10 2008

Dear all

I am new in using CosmoMC and I need to ask something that may be very easy.
I run cosmomc for "action=0".
The second column of the chain files output by CosmoMC which contain the -log(likelihood) is about 1329. I would like to know that does this parameter is "minimum (\chi^2)/2" or not ? I am doubtful about this since other peoples have reported the maximum -log(likelihood) about 800.

Thanks

Anze Slosar
Posts: 183
Joined: September 24 2004
Affiliation: Brookhaven National Laboratory
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minimun \\chi^2

Post by Anze Slosar » September 10 2008

Moslem,

Before continuously bombarding this forum with questions, you should carefully read and try to understand the cosmomc's README and the relevant papers, where the MCMC process is explained.

The second column of .txt files is the -log likelihood for that particular sample. Especially for the first hundred samples or so these are high as the chain is still in the burn-in phase. The exact numbers depend on datasets and models used.

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