[Mesa-users] Timestep issues

[Francis Timmes]

hi abdel,

this is not enough information for anyone to potentially help.
what is being modeled? what is the inlist?

mesa's time step controllers are described at 
https://docs.mesastar.org/en/latest/reference/controls.html#timestep-controls

fxt






> On Dec 3, 2021, at 3:45 PM, AbdelBassit Senhadji via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi MESA users! 
> 
> I am using the last version of MESA SDK with mesa-r15140. I am getting some issues with the time step and this is one of the errors:
> 
> 563D-01
>  retry: max resid -- give up in solver    3425
>  retry: logT > hydro_mtx_max_allowed_logT    3425
>                   max_residual > tol_max_residual*coeff        3425    9.0476669018875888D-06    2.3009034825276050D-06    2.3009034825276048D-01
>  retry: max resid -- give up in solver    3425
>  retry: logT > hydro_mtx_max_allowed_logT    3425
>                   max_residual > tol_max_residual*coeff        3425    9.0476677124568281D-06    2.3009027348566796D-06    2.3009027348566796D-01
>  retry: max resid -- give up in solver    3425
>  retry: logT > hydro_mtx_max_allowed_logT    3425
>                   max_residual > tol_max_residual*coeff        3425    9.0476661055005185D-06    2.3009040350088826D-06    2.3009040350088825D-01
>  retry: max resid -- give up in solver    3425
>                                                      dt    7.9272836255228435D-07
>                                      min_timestep_limit    9.9999999999999995D-07
> 
>  stopping because of problems dt < min_timestep_limit
> 
>  retry: logT > hydro_mtx_max_allowed_logT    3425
>                                                      dt    7.9272836255228435D-07
>                                      min_timestep_limit    9.9999999999999995D-07
> 
>  stopping because of problems dt < min_timestep_limit
> 
>                   check_rel_error_in_energy delta_value                       NaN
> STOP check_change
> DATE: 2021-12-03
> TIME: 17:30:34
> 
> ****************************
> 
> 
> The commands I use in the control settings were:
> 
>    time_delta_coeff
>     delta_HR_limit 
>     delta_HR_hard_limit 
> 
> 
> Any suggestion or recommendation on how to better control the timestep. I also attached the HR diagram I am having and want to have the evolution smoother without the spike lines. 
> 
> Thanks for your help!
> Abdel
> 
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