[Mesa-users] make_co_wd test case in r15140

[Silvana Vacchina]

Hi Kevin,

I found your problem interesting and I've tried myself to run this test
(make_co_wd), since I've been testing for a while with r15140 (it's really
good).

I can run the test without issues. I've only changed start_mass in the
inlist_common to set "initial_mass = 5.7d0" and activated "pgstar_flag =
.true.". There is a comment in the inlist that suggest that it is possible
to run this start_mass, I quote:
"! initial_mass in the range 1.0-6.5 Msun will produce CO WDs
 ! with masses 0.5-1.0 Msun."
Maybe there is another change involved in any place... in fact I don't
understand "And the environment variables are set to create a new zams
model each time." I can try more changes if you want, to rule out a model
or system problem (I can also attach results if needed).

Since I've found no issues, and since you've realized that it might require
some 16 GB, I can say that I'm working on Oracle Virtual Machine, with an
operating system Ubuntu (system and libraries as suggested for r15140),
with 32 GB RAM and assigning 10 cores to the calculations (you can check
the value of OP_NUM_THREADS).

I hope you find the way to make this work.

Cheers,
Silvana.

El jue, 13 ene 2022 a las 0:48, Evan Bauer via Mesa-users (<
mesa-users at lists.mesastar.org>) escribió:

> Hi Kevin,
>
> Thanks for calling attention to this. I don’t think you’re doing anything
> wrong per se. I’ve noticed that massive C/O WDs have gotten harder to
> produce with make_co_wd in recent MESA versions as well, and I can confirm
> that I run into similar convergence problems when starting with an initial
> mass of 5.7.
>
> I think the problem is that the solver is struggling to converge for the
> outer layers during some parts of the very luminous post-AGB evolution. I
> was able to get around this by adding this control in inlist_remove_env and
> inlist_settle:
>         Pextra_factor = 4
>
> That’s somewhat inspired by the test case wd_nova_burst, which also has a
> massive WD evolving through a similar luminous post-nova phase. This
> control might make some parts of the evolution slightly unrealistic, but if
> your goal is just to produce a fresh C/O WD model to work with, this should
> get your model where you want it to end up.
>
> Perhaps we can add this as a default in future MESA releases so that
> massive C/O WDs aren’t so hard to produce consistently.
>
> By the way, I think the RAM constraint that you were seeing comes from all
> of the EOS table caching that occurs during the relaxation phase if you
> haven’t run models through that range of composition space before on your
> MESA installation. I noticed that I had quite large RAM usage when I first
> ran the model and had many EOS tables to cache, but the next time I ran the
> model my RAM usage was much more reasonable.
>
> Cheers,
> Evan
>
> > On Jan 10, 2022, at 12:58 PM, Kevin Rorke via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >
> > Hi everyone
> >
> > I've been trying to run the make_co_wd test case in r15140 with a 5.7
> Msun (or thereabouts) starting mass for some time now. Previously the run
> failed during the inlist_remove_env step because of memory constraints - it
> seems to require about 16GB of RAM. But even with that amount of memory,
> the run eventually fails for any starting mass in that region.
> >
> > The only value I've changed is the initial_mass value in inlist_common.
> And the environment variables are set to create a new zams model each time.
> Can anyone suggest what I might be doing wrong?
> >
> > Cheers
> >
> > Kevin
> >
> >  Exceeded max_iters iterations in eval_T_tau_uniform
> >  retry: error in PT_eqns_surf    1887
> >                                                      dt
> 5.6302130558697700D-21
> >                                      min_timestep_limit
> 9.9999999999999995D-21
> >
> >  stopping because of problems dt < min_timestep_limit
> >
> >
> > terminated evolution: cannot find acceptable model
> >
> > termination code: min_timestep_limit
> > DATE: 2022-01-10
> > TIME: 19:24:41
> >
> > ******************************************************************
> > failed to create co_wd.mod when running inlist_remove_env_header
> > ******************************************************************
> >
> > <inlist_common.txt>_______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> >
>
> _______________________________________________
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>
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