[Mesa-users] Call to eos_proc failed in eval_fcn

[Thomas Steindl]

Hi Akaash, 

In general, it it advisable to include much more information about the specific problem including the MESA version, your inlists and run_stars_extras, if you have changed anything for anybody to help you. 
That said, I do not have much experience concerning white dwarfs, but I have come across this error message. For r12778 I have found that, if this is ok for your case, lowering the error tolerance for the atmosphere can help convergence:
atm_T_tau_errtol = 1d-5 (default 1d-7). 
You can also try to allow more iterations/steps for the integrations (atm_T_tau_max_iters = 50, atm_T_tau_max_steps = 500, these are the default values)

Best,
Thomas
__________________________________________________________________

Thomas Steindl, MSc
University of Innsbruck | Institute for Astro- and Particle Physics
Tel: +43 512507 52031
Mail: thomas.steindl at uibk.ac.at
Homepage: www.thomassteindl.com

> Am 09.08.2021 um 14:50 schrieb Akaash Conhye via Mesa-users <mesa-users at lists.mesastar.org>:
> 
> Hi all,
> 
> I'm running a simulation of a white dwarf with a 0.03 solar mass nickel envelope, but I'm getting this error just before my timestep tends to zero: 
> "Call to eos_proc failed in eval_fcn"
> 
>  This happens when I set the following in my inlist:
> atm_option = 'T_tau' 
> atm_T_tau_relation = 'Eddington' 
> atm_T_tau_opacity = 'varying'
> 
> I found that this error disappears when I set atm_T_tau_opacity = 'fixed' however my timestep still tends to zero at approximately the same stage in the white dwarf's evolution. I've also tried using atm_T_tau_opacity = 'iterated' which gives me the same result as 'varying'. My question is this: what does this error mean? is it something I should be concerned with?
> 
> Thanks
> Akaash
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