[Mesa-users] Timestep issues

[Francis Timmes]

hi abdel,

i won't be useful on the binary aspects, other than to suggest 
checking that the two models evolve as desired as single stars. 
there, smaller time step controls on the central temperature delta_lgT_cntr_limit
and on the central density delta_lgRho_cntr_limit are often useful for making
a model evolve based on changes of physical variables rather than numerical variables.

good luck!

fxt






> On Dec 8, 2021, at 9:20 PM, AbdelBassit Senhadji <sen-abd at hotmail.fr> wrote:
> 
> Hi Francis, 
> 
> Sorry for the late reply. I am evolving M1 = 5.5Msun for the donor and M2 = 3.79Msun for the companion. I evolved the system until the M1 filled the RL and became a WD. The secondary at that time had  a mass = 6.9 Msun, I applied high winds to strip all that mass from the secondary to get that secondary fills the RL while it is still a He burning star. 
> 
> From the HR diagram I attached, it is clear that something is wrong with my timestep. I also attached the inlists I am using. Which timestep I should change to get rid of these spikes and have a smooth evolution? The list of timesteps on MESA Sourcefouge is big and did not know which one I should change. 
> 
> 
> Thanks
> Abdel
> 
> De : Francis Timmes <fxt44 at mac.com>
> Envoyé : 4 décembre 2021 16:13
> À : AbdelBassit Senhadji <sen-abd at hotmail.fr>
> Cc : Frank Timmes <fxt44 at mac.com>; mesa-users <mesa-users at lists.mesastar.org>
> Objet : Re: [Mesa-users] Timestep issues
>  
> 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://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.mesastar.org%2Fen%2Flatest%2Freference%2Fcontrols.html%23timestep-controls&data=04%7C01%7C%7C3f2f11127c314dfb8d4008d9b76aeba3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637742492111486903%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=tH2%2FPDCEPhY8jNJAtyiP582EykpJYYJwtGbLEI0Dhv8%3D&reserved=0
> 
> 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
> > 
> > <Figure.pdf>_______________________________________________
> > mesa-users at lists.mesastar.org
> > https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.mesastar.org%2Fmailman%2Flistinfo%2Fmesa-users&data=04%7C01%7C%7C3f2f11127c314dfb8d4008d9b76aeba3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637742492111486903%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=oD1964UfOccAZfgF4txCZd74SjqQpceOxiVHPrbAO7I%3D&reserved=0
> 
> <inlist_project><inlist2>