[Mesa-users] rates confusion and soul searching

[Francis Timmes]

hi aaron,

with what version, and when, did this model run to your satisfaction?

fxt




> On Oct 23, 2019, at 7:39 AM, Aaron Dotter via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi again,
> 
> @Rob, thanks for your suggestion.  I changed the reaclib file but it didn't noticeably change the result in 11701.  The mystery continues . . . 
> 
> 
> I have put together a minimal working example in case anyone would like to help me figure this out.  Attached is a very minimal inlist and starting model. 
> 
> When I run this with a more recent revision (12155), it is able to sustain a reasonable timestep throughout core H-burning.  However, it accumulates a large error.  Maybe this is relevant; I don't know.
> 
> When I run the same with 11701, it starts doing retries and backups around model #730.  It ends with a min_timestep_limit at 750.
> 
> When I then turn on debugging output to the terminal, still in 11701, it rather dramatically changes the result.  The model still struggles (shorter timesteps, more retries + backups) but it is able to keep going up until the stopping condition at model #1000. 
> 
> One final note is that I'm no longer suspicious that this is related to weak reactions.  I tried setting the T9_weaklib_full_on/off to 1.0 and nothing changed.
> 
> 
> Changing MESA revisions is not a viable option at this point -- I need to get this working in 11701 if at all possible.
> 
> 
> Thanks,
> Aaron
> 
> 
> On Tue, Oct 22, 2019 at 4:30 PM Rob Farmer <r.j.farmer at uva.nl> wrote:
> Hi,
> 
> What happens if you try one of the older JINA/REACLIB files (see $MESA_DIR/data/rates_data) jina_reaclib_filename = 'jina_reaclib_results_v2.2' for the previous version.
> 
> Rob
> 
> On Tue, 22 Oct 2019 at 16:08, Aaron Dotter via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> Hi folks,
> 
> I'm having one of those Heisenbug days, where I just can't figure out what I'm doing wrong.  Hoping that some can point me in a productive direction.  I'm running a model that I've recently run successfully, where "success" is defined as making it through core H-burning without any reties or backups in about 1000 timesteps.  Using rev 11701 with the 20190830 SDK, gfortran 9.2.0.
> 
> I'm using pp_and_cno_extras.net with JINA rates (new_rates_preference=2) in a low-mass star (0.7 Msun) starting from the pre-main sequence.  Normally this cruises through core H-burning without issue.  Today it grinds to a halt, evolutionarily-speaking, when the core T goes above ~10^7 K (logdt < 0) and starts doing lots of retries.  I'm also using set_initial_xa_from_file to set the initial abundances for all species in the inlist -- this has caused some surprises in the past (looking at boron-8 here).
> 
> I don't have a MWE at the moment but if this drags on into tomorrow, I'll make one.
> 
> When the run starts, before listing the rate cache files written by MESA, I get these two lines printed to the terminal, over and over again maybe hundreds of times:
> 
> r_ne18_wk_f18 failed in do_jina_reaclib     321
> r_ne19_wk_f19 failed in do_jina_reaclib     324
> 
> I've tried removing/cleaning caches (data/rates_data/cache, my MESA_CACHES_DIR, and .mesa_temp_cache in my work directory).  This doesn't fix the problem.
> 
> If I switch to NACRE (new_rates_preference=1 then the model evolves as I would like it to.  This and the error message make me think I've run afoul of some weird rates problem.
> 
> If confronted with this problem, what would you try next? 
> 
> Thanks!
> Aaron
> 
> 
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