[Mesa-users] Questions about the debugging controls

[Jeremy Sakstein]

Thanks Rob,

I will do this and send you the output.

Just to check: I want to use report_hydro_solver_progress correct? I
couldn't find a control called report_solver_progress in the controls (I'm
using 12778).

Cheers,

Jeremy

On Tue, Aug 17, 2021 at 4:53 AM Rob Farmer <robert.j.farmer37 at gmail.com>
wrote:

> grep -rinI 'log eps nuc ratio' star/p*/*
> star/private/timestep.f90:1703:            if (s% report_all_dt_limits)
> write(*,4) 'log eps nuc ratio', &
>
> That leads to the function check_dlog_eps_nuc_change, note there are some
> divide by eps_nuc's in there. So having 0's floating around (when you set
> eps_nuc_factor to 0) is not going to help. I would suggest just using s%
> dxdt_nuc_factor = 0d0  which turns off composition change from burning but
> keeps eps_nuc set. That way your star won't just collapse as it runs out of
> nuclear energy.
>
> Try setting
> report_solver_progress = .true.
>
> and send the output for a step that seems to cause problems.
>
> Rob
>
>
>
> On Mon, 16 Aug 2021 at 20:31, Jeremy Sakstein <sakstein at hawaii.edu> wrote:
>
>> Hi everyone,
>>
>> I've been having some convergence issues so I used the debugging controls:
>>
>> report_why_dt_limits
>> report_all_dt_limits
>> report_hydro_dt_info
>>
>> To try to figure out what is causing them. These helped a lot and I have
>> been able to push the model much further but I am still unable to get full
>> convergence so I wanted to ask a couple of questions.
>>
>> Currently, when I turn on report_why_dt_limits it just tells me
>>
>> "timestep_hold > model_number, so no timestep increase"
>>
>> If I also turn on report_all_dt_limits it tells me "log eps nuc ratio"
>> followed by some ratios so I assume that eps_nuc is what is limiting the
>> timestep? Is this the correct interpretation of this information?
>>
>> When I set
>>
>>    delta_log_eps_nuc_limit = -1
>>    delta_log_eps_nuc_hard_limit = -1
>>
>> I still get this message, which confused me a bit because surely this
>> means that eps_nuc should no longer limit the timestep?
>>
>> As an extreme test, I updated extras_start_step to set
>>
>> s% dxdt_nuc_factor = 0d0
>>
>> s% eps_nuc_factor = 0d0
>>
>> which I think should effectively turn off nuclear burning. Indeed, the
>> abundances don't seem to change but I still get the same eps_nuc warning
>> from report_all_dt_limits.
>>
>> Is someone able to tell me whether these changes are doing what I
>> expected given my output?
>>
>> It would be great if someone could suggest either further ways I can
>> determine what is limiting the timestep, or how to stop eps_nuc limiting
>> the timestep if this is really what is happening.
>>
>> Cheers,
>>
>> Jeremy
>>
>>
>>
>>
>> --
>> Jeremy Sakstein (He/Him/His)
>> Assistant Professor of Theoretical Physics
>> Department of Physics & Astronomy
>> University of Hawaiʻi at Mānoa
>> Watanabe Hall
>> 2505 Correa Road
>> Honolulu, HI, 96822, USA
>> http://www.jeremysakstein.com
>> _______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>
>>

-- 
Jeremy Sakstein (He/Him/His)
Assistant Professor of Theoretical Physics
Department of Physics & Astronomy
University of Hawaiʻi at Mānoa
Watanabe Hall
2505 Correa Road
Honolulu, HI, 96822, USA
http://www.jeremysakstein.com
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