[Mesa-users] Questions about the debugging controls

[Jeremy Sakstein]

Hi everyone,

I've been having some convergence issues so I used the debugging controls:

report_why_dt_limits
report_all_dt_limits
report_hydro_dt_info

To try to figure out what is causing them. These helped a lot and I have
been able to push the model much further but I am still unable to get full
convergence so I wanted to ask a couple of questions.

Currently, when I turn on report_why_dt_limits it just tells me

"timestep_hold > model_number, so no timestep increase"

If I also turn on report_all_dt_limits it tells me "log eps nuc ratio"
followed by some ratios so I assume that eps_nuc is what is limiting the
timestep? Is this the correct interpretation of this information?

When I set

   delta_log_eps_nuc_limit = -1
   delta_log_eps_nuc_hard_limit = -1

I still get this message, which confused me a bit because surely this means
that eps_nuc should no longer limit the timestep?

As an extreme test, I updated extras_start_step to set

s% dxdt_nuc_factor = 0d0
s% eps_nuc_factor = 0d0

which I think should effectively turn off nuclear burning. Indeed, the
abundances don't seem to change but I still get the same eps_nuc warning
from report_all_dt_limits.

Is someone able to tell me whether these changes are doing what I expected
given my output?

It would be great if someone could suggest either further ways I can
determine what is limiting the timestep, or how to stop eps_nuc limiting
the timestep if this is really what is happening.

Cheers,

Jeremy




--
Jeremy Sakstein (He/Him/His)
Assistant Professor of Theoretical Physics
Department of Physics & Astronomy
University of Hawaiʻi at Mānoa
Watanabe Hall
2505 Correa Road
Honolulu, HI, 96822, USA
http://www.jeremysakstein.com
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