sampling method for PlanckTP + Planck SZ(SZ_plus_CMB.ini)

Use of Healpix, camb, CLASS, cosmomc, compilers, etc.
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Zhen Pan
Posts: 12
Joined: August 29 2017
Affiliation: UC Davis

sampling method for PlanckTP + Planck SZ(SZ_plus_CMB.ini)

Post by Zhen Pan » September 21 2017

I am testing

Code: Select allp>

sampling_method = 7
and run
mpirun -np 6 ./cosmomc xx.ini
but it seems to be a bad choice: the chains only move 1−3 steps in the first 30 mins.

Anyone knows which sampling method to use here ?

Antony Lewis
Posts: 1352
Joined: September 23 2004
Affiliation: University of Sussex
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Re: sampling method for PlanckTP + Planck SZ(SZ_plus_CMB.ini

Post by Antony Lewis » September 21 2017

You can use method 1 to use standard Metropolis Hastings.

Also check your parameter propose widths: make sure they are small enough so that chain can move. (the SZ likelihood may also be slow, I'm not sure, I've not written or used it myself).

Zhen Pan
Posts: 12
Joined: August 29 2017
Affiliation: UC Davis

sampling method for PlanckTP + Planck SZ(SZ_plus_CMB.ini)

Post by Zhen Pan » September 21 2017

Thank you, Antony. I am using method=1 now.

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