Any (consistency) problem with running cosmomc for default values AND \Omega_k >= 0.15 ?

[Patrice Okouma]

Dear all

I am having problems with forcing Cosmo MC to look at very positive values of Omega_k (Omega_k >= 0.1)

If I run Cosmo MC, eg. May 2010 version, leaving all default values in params.ini the same except Omega_k, the program aborts almost immediately with the message:

MCMC.f90: Couldn't start after 1000 tries - check starting ranges

This happens for instance for Omega_k fixed to 0.05 but not lower. I wonder if there is some conflict somewhere.

Somewhere else it is suggested to modify the allowed range for theta parameter .
I've tried that but it does not seem to be working

Could you help please.
Thanking you.
Patrice

[Antony Lewis]

The problem is probably in ParamsToCMBParams in params_CMB.f90. Also check your central starting value of \theta is consistent with your choice of \Omega_K (e.g. if other parameters are at default values, around 0.81; but presumably for this to be sensible you do have other parameters changed otherwise data would easily rule it out, so better to change all starting values appropriately).

Or you could replace params_CMB with a parameterization based on H_0 instead of \theta (e.g. params_H.f90).

[Patrice Okouma]

Thanks.
The latest params_H.f90 is not available inside cosmomc May 2010.
Plz, where can I get it ?
Is the probably old version still compatible with the latest cosmomc
(I am using the May 2010 version) ?

Thanks.
Patrice