[Mesa-users] rel_run_E_err zone

[Morgan Taylor]

Hi Ali,

>and what is the exact definition?

Opening up $MESA_DIR/star/defaults/controls.defaults and searching for the
term shows:

      ! warn_when_large_rel_run_E_err
      ! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ! message includes the text "WARNING: rel_run_E_err"
      ! rel_run_E_err = abs(cumulative_energy_error/total_energy)
      ! you can turn off this warning message by setting this to a large
number.
      ! ::
    warn_when_large_rel_run_E_err = 0.01d0

The definition for rel_run_E_error is then the absolute value of the
cumulative energy error (error summed over all zones) over the total
energy.

You can change the max_abs_rel_run_E_err = 0.01d0 parameter in your control
settings. A negative value will ignore it entirely.

>I was wondering if there is a way to check when the terminal output shows
the rel_run_E_err warning, to be able to actually see in which zone of the
structure this rel_run_E_err is happening?

To find where (zone) the largest "problem" is, you can utilize   abs_rel_E_err
= maxval(abs(s% rel_E_err(1:s% nz))).
This parameter tells you the max value of the relative energy error from
all the zones.
To find the location of the max value, I suggest adding something along the
following to your run_star_extras.90 file, perhaps in the
 extras_finish_step routine:

if (s % run_rel_E_err > 0.009) then
  write(*,*) 'MAX LOCATION OF REL ENERGY ERR:', maxloc(abs(s%
rel_E_err(1:s% nz))
end if

This checks if the run_rel_E_error gets 'near' the default error warning
value of 0.01.
If so, it will print to the terminal the message in the if statement. Just
remember MESA starts its first zone at the surface ;)

>Is this quantity being saved anywhere actually,

If you want to report the rel_run_E_err (cumulative energy error) value to
understand when in the evolution the error gets large,
you can add it to what you want included in the history.data file.
Simply add rel_run_E_err to your history_columns.list file.
You can also add its pieces to the history_columns.list file for a more
thorough analysis:

      !error_in_energy_conservation ! for this step
         ! = total_energy - (total_energy_start +
total_energy_sources_and_sinks)
      !cumulative_energy_error ! = sum over all steps of
error_in_energy_conservation
      !rel_cumulative_energy_error ! = cumulative_energy_error/total_energy
      !log_rel_cumulative_energy_error ! = log10 of
rel_cumulative_energy_error
      !log_rel_run_E_err ! shorter name for rel_cumulative_energy_error
      !rel_error_in_energy_conservation ! =
error_in_energy_conservation/total_energy
      !log_rel_error_in_energy_conservation

Simply add the term(s) you want reported to your history_columns.list file.
Those terms will then be reported in your history.data file.
(A full list of possible parameters to show up in your history.data file is
found in $MESA_DIR/star/defaults/history_columns.list.
You can copy this to your working directory and uncomment any parameter you
want included to the history.data file.)

Hope this helps!

Morgan

On Mon, Apr 17, 2023 at 7:01 AM Ali Pourmand via Mesa-users <
mesa-users at lists.mesastar.org> wrote:

> Hello,
>
> I was wondering if there is a way to check when the terminal output shows
> the rel_run_E_err warning, to be able to actually see in which zone of the
> structure this rel_run_E_err is happening?
>
> Is this quantity being saved anywhere actually, and what is the exact
> definition?
>
> best
> Ali Pourmand
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
>
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