Hi,
I installed the last version of cosmomc on a cluster. I tried to launch a chain on 20 nodes and with 200000 samples. But the problem is that the chain stopped after 4000 samples and not 200000. I don't understand how work MPI with cosmomc. Can you explain me please?
Thank you in advance.
Cosmomc & MPI
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Antony Lewis
- Posts: 1944
- Joined: September 23 2004
- Affiliation: University of Sussex
- Contact:
Re: Cosmomc & MPI
By default the chains stop when they have converged, 4000 samples is probably about right. Tweak the convergence settings in the .ini file if you want them to be more converged, but 200K samples is almost certainly a waste of computer time. Usually you only need 4-8 chains, not much to be gained by using 20.
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Pierre Delsart
- Posts: 14
- Joined: October 28 2008
- Affiliation: tt
Cosmomc & MPI
Thank you Antony. I set to -1 the value for the MPI convergence in the .ini file. I'll see if there is a change.