[Mesa-users] dt_limit: max increase and decrease

Pablo Marchant pamarca at gmail.com
Fri Feb 2 08:33:17 EST 2018


Hi Jackie,

Say varcontrol determines your timestep should change from 1 year to 0.1
years. If max_decrease=0.5 then it will only be change to 0.5 years. Same
with max_increase. This is mean to avoid large changes in timestep from
step to syep.

Cheers

On Feb 2, 2018 6:15 AM, "Jacqueline Goldstein via Mesa-users" <
mesa-users at lists.mesastar.org> wrote:

> I am running the simplex module in MESA r10081 and see dt_limit outputs
>  ‘max increase’ and ‘max decrease’ but don’t understand what these are.
>
> I see the output is set here
> star/private/star_private_def.f90:         dt_why_str(Tlim_max_timestep_factor)
> = 'max increase’
> star/private/star_private_def.f90:         dt_why_str(Tlim_min_timestep_factor)
> = ‘min increase’
>
> And that the timestep factor is defined here
> star/public/star_def.inc:      integer, parameter ::
> Tlim_max_timestep_factor = Tlim_struc + 1
> star/public/star_def.inc:      integer, parameter ::
> Tlim_min_timestep_factor = Tlim_max_timestep_factor + 1
> s
>
> where Tlim_struc is defined
> star/public/star_def.inc:      integer, parameter :: Tlim_struc = 1
>
> and set to ‘varcontrol’ here
> star/private/star_private_def.f90:         dt_why_str(Tlim_struc) =
> ‘varcontrol'
>
> Conceptually I understand that Varcontrol limits how much a variable is
> allowed to change between steps, but can someone help me follow that up the
> chain to understand what max increase and min increase are?
>
> Thank you,
>
> Jacqueline Goldstein
> PhD Graduate Student | Astronomy
> University of Wisconsin - Madison
> http://www.astro.wisc.edu/~jgoldstein
>
>
>
>
>
>
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
>
>
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