[Mesa-users] make_co_wd test case in r15140

Kevin Rorke kevin.rorke at gmail.com
Thu Jan 13 20:14:33 UTC 2022


Hi Silvana

Thanks for your interest. It is always helpful to see if somebody else 
is independently getting the same results!

One of the steps that the make_co_wd test case does is to create a ZAMS 
model of the required mass to begin with; but as I understand it, if you 
want to run the case with a different initial mass, you will need to set 
an environment parameter to make this happen.

So if you execute this:

export mesa_run_optional=t

from the command line and re-run the case for a starting mass of 5.7M, 
does the case still complete successfully?

I'm also running my version of MESA on Ubuntu in a VMWare VM, and I had 
wondered previously if the virtualisation had somehow affected the test 
case.

Regards

Kevin

On 1/13/22 9:53 PM, Silvana Vacchina via Mesa-users wrote:
> 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 
> <mailto: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
>     <mailto: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
>     > ******************************************************************
>     >
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