[Mesa-users] Time step

[Nsamba Benard]

Thank you Bill
----------------------------------------------------------------------------------------------------------
Benard Nsamba
PhD student                                       Centro de Astrofisica
                                                           Universidade do
Porto
                                                           Rua das Estrelas
Tel: +351 920 404 108                      4150-762 Porto, Portugal
E-mail: benard.nsamba at astro.up.pt <Benard.Nsamba at astro.up.pt>
Skype: benardnsamba
website: https://nsambabenard2net.wixsite.com/mysite


On Wed, Nov 7, 2018 at 7:00 PM Bill Paxton <paxton at kitp.ucsb.edu> wrote:

> note that there are both “limits” and “hard_limits” for time steps.  in
> particular,
>
>          !### delta_lg_XH_cntr_limit
>
>          ! If max delta is greater than this,
>          ! reduce the next timestep by
> `delta_lg_XH_cntr_limit`/`max_delta`.
>
>       delta_lg_XH_cntr_limit = 0.05d0
>
>          !### delta_lg_XH_cntr_hard_limit
>
>          ! If max delta is greater than `delta_lg_XH_cntr_hard_limit`,
>          ! retry with smaller timestep.
>
>       delta_lg_XH_cntr_hard_limit = -1
>
> The limit impacts the setting for the NEXT timestep.  So it comes into
> effect for step 2 and beyond, not for step 1.
>
> If you want step 1 to also satisfy the limit, you can set the
> “hard_limits” which will force a retry of step 1.
>
>
> -bill
>
>
> On Nov 7, 2018, at 10:06 AM, Nsamba Benard via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
> Hello,
>
> I have been playing around with specifying timesteps based on only
> variations in  central hydrogen abundance (Xc). The lines below specific
> this in the inlist.
>
>     delta_lg_XH_cntr_limit = 0.005
>     delta_lg_XH_cntr_max = 0
>
> However looking at the Xc difference between models, I find a couple of consecutive
> models with a different difference in Xc to that specified in my inlists
> (See attached histogram).
> In my terminal during the runs, its clearly shown that "lg_XH_cntr"
> controls the steps as expected except for the first two models.
>
> Can someone help me understand why a few of my models don't conform to
> this specification? How can I fix this?
>
> Thank you in advance for your help
>
> Cheers,
> Benard
>
> ----------------------------------------------------------------------------------------------------------
> Benard Nsamba
> PhD student                                       Centro de Astrofisica
>                                                            Universidade do
> Porto
>                                                            Rua das Estrelas
> Tel: +351 920 404 108                      4150-762 Porto, Portugal
> E-mail: benard.nsamba at astro.up.pt <Benard.Nsamba at astro.up.pt>
> Skype: benardnsamba
> website: https://nsambabenard2net.wixsite.com/mysite
> <hist.png><inlist_2><inlist_cluster><inlist><s1.mod>
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