# astero_search_controls

## \(\chi^2\) weights

### chi2_seismo_fraction

The optimization methods will use and report a total \(\chi^2\) that
is a weighted sum of
seismic and “spectroscopic” (really “non-seismic”)
parts. `chi2_seismo_fraction`

is the weight given to the seismic
part. i.e. the code internally evaluates something like

```
chi2 = chi2_seismo*chi2_seismo_fraction
+ chi2_spectro*(1 - chi2_seismo_fraction)
```

```
chi2_seismo_fraction = 0.667d0
```

## Non-seismic (“spectroscopic”) observations

`chi2_spectro`

is a sum of terms for different non-seismic
observables (e.g. Teff, logg, [Fe/H]). These controls specify what
quantities are added to this \(\chi^2\) and, in some cases, how they
are computed.

Each component is identified by setting its name to either a string
matching a history column or one of the cases defined in `run_star_extras.f90`

.
If target value and uncertainty `sigma`

are greater than zero, a \(\chi^2\) component
will be computed and output in the sample data.

If `include_in_chi2_spectro`

is set to `.true.`

, that component will be included
in `chi2_spectro`

. The old fixed options were equivalent to:

`Teff`

`log_g`

`log_L`

`log_R`

`M_H`

(was`FeH`

)`surface_Z_div_X`

`surface_He`

`Rcz`

where `M_H`

, `surface_Z_div_X`

, `surface_He`

and `Rcz`

are now implemented in the standard ``run_star_extras.f90`.
The other options fall back to the history columns.

To implement your own constraints, create the appropriate case
in `set_constraint_value`

in `run_star_extras.f90`

.

The `age`

option is still treated separately because there are
additional controls that determine how the age target is
approached.

Target values must be set separately for PGstar. If you want
targets to appear in the `loggTe`

window, you need to set
the following PGstar controls:

```
loggTe_target_logg
loggTe_target_logg_sigma
loggTe_target_Teff
loggTe_target_Teff_sigma
```

Similarly, if you want targets to appear in the HR window, you need to set the following PGstar controls:

```
HR_target_logL
HR_target_logL_sigma
HR_target_Teff
HR_target_Teff_sigma
```

### constraint_name(:)

### include_constraint_in_chi2_spectro(:)

### constraint_target(:)

### constraint_sigma(:)

constraint_name(:) = ‘’ ! change this to whatever you want constraint_target(:) = 0 constraint_sigma(:) = 0 include_constraint_in_chi2_spectro(:) = .false.

### normalize_chi2_spectro

If `.true.`

, the total \(\chi^2\) computed for the non-seismic
components (defined above) is divided by the number of components
used to define it.

```
normalize_chi2_spectro = .true.
```

### Z_div_X_solar

Convenience parameter leftover from the old interface that can be used when calculating things relative to solar metallicity.

Z_div_X_solar = 0.02293d0

### include_age_in_chi2_spectro

### age_target

### age_sigma

`age`

is the star’s age in years. When you
`include_age_in_chi2_spectro`

, set `min_age_for_chi2`

and
`max_age_for_chi2`

, and set `eval_chi2_at_target_age_only`

to
`.false.`

. In `&control`

, set `max_years_for_timestep`

but don’t set
`max_age`

or `num_adjusted_dt_steps_before_max_age`

.

```
include_age_in_chi2_spectro = .false.
age_target = 4.5695d9 ! (see Bahcall, Serenelli, and Basu, 2006)
age_sigma = 0.0065d9
```

### num_smaller_steps_before_age_target

```
num_smaller_steps_before_age_target = 50 ! only used if > 0
```

### dt_for_smaller_steps_before_age_target

This should be much smaller than `age_sigma`

.

dt_for_smaller_steps_before_age_target = 0.0065d8 ! 1/10 age_sigma

## Seismic observations

### chi2_seismo_delta_nu_fraction

### chi2_seismo_nu_max_fraction

### chi2_seismo_r_010_fraction

### chi2_seismo_r_02_fraction

`chi2_seismo`

is a weighted combination of the large separation
\(\Delta\nu\), the frequency of maximum oscillation power
\(\nu_\mathrm{max}\), ratios of frequencies and individual
frequencies. Specify the weighting of the terms in
`chi2_seismo`

by setting these controls. Naturally, all the
fractions must be between zero and one. If the relevant
fraction is not zero, the corresponding target values and
uncertainties must be set.

```
chi2_seismo_delta_nu_fraction = 0d0 ! if > 0 then delta_nu and delta_nu_sigma must be set (see below)
chi2_seismo_nu_max_fraction = 0d0 ! if > 0 then nu_max and nu_max_sigma must be set (see below)
chi2_seismo_r_010_fraction = 0d0 ! if > 0, then include r_010 frequency ratios
chi2_seismo_r_02_fraction = 0d0 ! if > 0, then include r_02 frequency ratios
```

The fraction for the frequencies is whatever is left. i.e.

```
fraction for frequencies = 1 - (frac_r_010_ratios + frac_r_02_ratios + frac_delta_nu + frac_nu_max)
```

so if you only want to use individual frequencies in
`chi2_seismo`

, set all four fractions to zero.

### normalize_chi2_seismo_frequencies

### normalize_chi2_seismo_r_010

### normalize_chi2_seismo_r_02

The terms for the frequencies and ratios are sums of terms for each frequency and ratio. If you normalize them, they are divided by that number of terms.

```
normalize_chi2_seismo_frequencies = .true.
normalize_chi2_seismo_r_010 = .true.
normalize_chi2_seismo_r_02 = .true.
```

### trace_chi2_seismo_delta_nu_info

### trace_chi2_seismo_nu_max_info

### trace_chi2_seismo_ratios_info

### trace_chi2_seismo_frequencies_info

### trace_chi2_spectro_info

If `.true.`

, output information on that \(\chi^2\) component to the terminal.

```
trace_chi2_seismo_delta_nu_info = .false.
trace_chi2_seismo_nu_max_info = .false.
trace_chi2_seismo_ratios_info = .false.
trace_chi2_seismo_frequencies_info = .false.
trace_chi2_spectro_info = .false. ! if true, output info to terminal
```

### nu_max

### nu_max_sigma

`nu_max`

is the frequency of maximum oscillation power. You must set this value if
`chi2_seismo_nu_max_fraction`

is greater than zero.

```
nu_max = -1
! nu_max is needed when
! chi2_seismo_nu_max_fraction > 0 or correction_factor > 0 (see below)
nu_max_sigma = -1
```

### delta_nu

### delta_nu_sigma

`delta_nu`

is the large frequency separation (roughly constant
frequency difference between radial modes of increasing order) .
You must set this value if `chi2_seismo_delta_nu_fraction`

is
greater than zero.

```
delta_nu = -1
delta_nu_sigma = -1
```

If `delta_nu`

in the inlist is greater than zero, the
code uses the inlist values for both `delta_nu`

and
`delta_nu_sigma`

.

If `delta_nu`

is less than or equal to zero in the inlist, the code estimates it
by a linear fit to the observed radial frequencies and orders, `l0_obs`

and `l0_n_obs`

.

Along with calculating `delta_nu`

, if `delta_nu_sigma`

from the inlist is less than zero, then the code also sets
it by using the radial data. Note that by setting
`delta_nu_sigma`

to a positive value and `delta_nu`

to
a negative value, you can have the code get `delta_nu`

from the given `l0_obs`

and `l0_n_obs`

, while still
using the `delta_nu_sigma`

from the inlist.

## Mode frequency data

### nl

### freq_target

### freq_sigma

Data for oscillation modes. `nl(el)`

is the number of modes of degree `el`

,
`freq_target(el,1)`

to `freq_target(el,nl(el))`

are the
frequencies (in increasing frequency order) and `freq_sigma(el,1)`

to `freq_sigma(el,nl(el))`

are
the uncertainties.

```
nl(0:3) = 0 ! number of observed modes
freq_target(0:3,:) = 0 ! frequencies. set e.g. freq_target(0,1) ... freq_target(0,nl(0)) for radial modes
freq_sigma(0:3,:) = 0 ! freq_sigma(el,i) is uncertainty for freq_target(el,i)
```

### l0_n_obs

`l0_n_obs(i)`

is the radial order of `l0_obs(i)`

for `i=1, nl0`

.
Need to give these if the code is to calculate `delta_nu`

and `delta_nu_sigma`

.
If you provide `delta_nu`

, then you don’t need to set these.
If `l0_n_obs`

are provided, the Kjeldsen surface correction will use them.

```
l0_n_obs(:) = -1
```

## Optimization method

### eval_chi2_at_target_age_only

Set this to `.true.`

if you only want \(\chi^2\) for a specific age
and no others. In addition, set `max_age`

, `max_years_for_timestep`

and `num_adjusted_dt_steps_before_max_age`

.

```
eval_chi2_at_target_age_only = .false.
```

### min_age_for_chi2

### max_age_for_chi2

Use these if you only want to evaluate chi2 for a given range of ages.

```
min_age_for_chi2 = -1 ! (years) only use if > 0
max_age_for_chi2 = -1 ! (years) only use if > 0
```

### search_type

This specifies the kind of search to perform, each of which has its own separate controls further on. The options are

`use_first_values`

This option means no search. Just do a single run using

`first`

values for the parameters.`scan_grid`

Evaluates \(\chi^2\) for each parameter combination within the

`min`

and`max`

ranges specified below, with the spacing defined by`delta`

.For a first rough scan, consider setting

`chi2_seismo_delta_nu_fraction = 1`

, which skips the relatively costly calculations of frequencies and simply uses`delta_nu`

along with the non-seismic information. You can then follow up with medium resolution scans in smaller regions around candidates from the rough scan with`chi2_seismo_delta_nu_fraction = 0`

to include frequencies.`simplex`

Search for minimal \(\chi^2\) model using Nelder-Mead simplex algorithm:

Nelder, J. A. and Mead, R. "A Simplex Method for Function Minimization." Comput. J. 7, 308-313, 1965.

There are versions of this in Numerical Recipes under the name “amoeba”, in Matlab under the name “fminsearch”, and in Mathematica as an option for “NMminimize”. Our version has lots of bells and whistles and is, of course, superior to the others. ;)

`newuoa`

Search for minimal \(\chi^2\) model using Powell’s NEWUOA algorithm for unconstrained minimization without derivatives by quadratic polynomial approximation.

M.J.D. Powell, "Developments of NEWUOA for unconstrained minimization without derivatives", Department of Applied Mathematics and Theoretical Physics, Cambridge, England, report NA05, 2007.

`bobyqa`

Search for minimal \(\chi^2\) model using Powell’s “Bounded Optimization BY Quadratic Approximation” (BOBYQA) algorithm. Any location within the bounds is available for consideration.

M.J.D. Powell, "The BOBYQA algorithm for bound constrained optimization without derivatives", Department of Applied Mathematics and Theoretical Physics, Cambridge, England, report NA06, 2009.

`from_file`

Calculates \(\chi^2\) for the parameter values in a given file. For each line of the file (after the first, which has column names), set the parameter values to that of the file for those parameters with

`vary_param = .true.`

.

The two methods from Powell use quadratic interpolation, either unconstrained (NEWUOA) or bounded (BOBYQA). The Nelder-Mead simplex method doesn’t interpolate; instead it simply compares values and moves toward lower \(\chi^2\) and away from higher ones. In general, you can expect the Powell methods to converge faster than the simplex if the \(\chi^2\) terrain is not too “bumpy” (bumps confuse the interpolation). Since the simplex scheme doesn’t do interpolation, bumps don’t cause it as much trouble, so it may be more robust. If you are just getting started, go with simplex at first. Try the interpolation methods when you have a very good candidate and want to look near it for even better results.

```
search_type = 'use_first_values'
```

### scan_grid_output_filename

Output goes to the following file when `search_type = 'scan_grid'`

.

```
scan_grid_output_filename = 'scan_grid_results.data'
```

### restart_scan_grid_from_file

If `.true.`

, reads the `scan_grid_output`

file
and continues from where that stopped.

```
restart_scan_grid_from_file = .false.
```

### simplex_itermax

Maximum number of iterations of the downhill simplex.

```
simplex_itermax = 1000 ! each iteration revises the simplex
```

### simplex_fcn_calls_max

Maximum number of function calls for the downhill simplex. One iteration may use several function calls. Each “function call” is a stellar evolution track to get a \(\chi^2\).

```
simplex_fcn_calls_max = 10000
```

### simplex_x_atol

### simplex_x_rtol

Terminate the simplex if the differences between iterations are less than either of these tolerances.

```
simplex_x_atol = 1d-10 ! tolerance for absolute differences
simplex_x_rtol = 1d-10 ! tolerance for relative differences
```

If you want the details, here’s the snippet of code.
`simplex(i,j)`

is value of `i`

-th parameter for point `j`

.
`l`

is the index of the best point.
There are `n`

parameters and `n+1`

points.

```
term_val_x = 0
do j=1,n+1 ! check each point
if (j == l) cycle ! l is the best point; so skip it
do i=1,n ! check each coordinate of point j vs point l
term1 = abs(simplex(i,j)-simplex(i,l)) / &
(x_atol + x_rtol*max(abs(simplex(i,j)), abs(simplex(i,l))))
if (term1 > term_val_x) term_val_x = term1
end do
end do
if (term_val_x <= 1d0) exit ! converged
```

### simplex_chi2_tol

Terminate the simplex if the best point has a \(\chi^2\) less than this.

```
simplex_chi2_tol = 1d-10 ! tolerance for chi^2
```

### simplex_centroid_weight_power

Each iteration starts by doing a reflection
of the worst point through the centroid of the others.
The centroid points are weighted by `(1/chi^2)**power`

.
`power = 0`

gives the standard unweighted centroid.
`power > 0`

shifts the reflection towards the better points.

```
simplex_centroid_weight_power = 0d0
```

### simplex_enforce_bounds

If `.true.`

, points outside the bounds will be rejected without evaluation.
If `.false.`

, the bounds will only be used when creating the initial simplex
and for adaptive random search.

```
simplex_enforce_bounds = .false.
```

### simplex_adaptive_random_search

This flag controls what is done if the standard options of reflect or contract
fail to produce a improvement in the simplex.
If `.true.`

, test uniform random samples within the bounds until a better point is found.
If `.false.`

, shrink the simplex toward the best point.

```
simplex_adaptive_random_search = .false.
```

### simplex_output_filename

Filename for the simplex output.

```
simplex_output_filename = 'simplex_results.data'
```

### restart_simplex_from_file

If `.true.`

, then reads the output file (`simplex_output_filename`

)
and continues from where that stopped
using the best \(n+1\) results as the initial simplex
(where \(n\) is the number of parameters).
Note that this restores the best simplex but you may still
see it rerun recent cases if they were not good enough to be
included in the simplex. We don’t restore the information
about those failed attempts, so we need to rerun them.

```
restart_simplex_from_file = .false.
```

### simplex_seed

Integer seed for random number generation.

```
simplex_seed = 1074698122 ! seed for random number generation
```

### simplex_alpha

Coefficients for the reflection step of the downhill simplex algorithm.

```
simplex_alpha = 1d0 ! reflect
```

### simplex_beta

Coefficients for the expansion step of the downhill simplex algorithm.

```
simplex_beta = 2d0 ! expand
```

### simplex_gamma

Coefficients for the contraction step of the downhill simplex algorithm.

```
simplex_gamma = 0.5d0 ! contract
```

### simplex_delta

Coefficients for the shrink step of the downhill simplex algorithm.

```
simplex_delta = 0.5d0 ! shrink
```

### newuoa_output_filename

Filename for the NEWUOA output.

```
newuoa_output_filename = 'newuoa_results.data'
```

### newuoa_rhoend

This is the tolerance that determines relative accuracy of final values
i.e., NEWUOA stops when results are changing by less than this.
See `mesa/num/public/num_newuoa`

for details.

```
newuoa_rhoend = 1d-6
```

### bobyqa_output_filename

Filename for the BOBYQA output.

```
bobyqa_output_filename = 'bobyqa_results.data'
```

### bobyqa_rhoend

This is the tolerance that determines relative accuracy of final values
i.e., BOBYQA stops when results are changing by less than this.
See `mesa/num/public/num_bobyqa`

for details.

```
bobyqa_rhoend = 1d-6
```

### filename_for_parameters

Filename containing parameter values when `search_type = 'from_file'`

.

```
filename_for_parameters = 'undefined'
```

### max_num_from_file

If greater than zero, stop `from_file`

search after trying this
many lines from the file.

max_num_from_file = -1 ! if > 0, then stop after doing this many lines from file.

### file_column_for_param

You need to say which columns in the file hold the various parameters. For example, if your file starts like the following:

```
chi2 mass init_Y init_FeH alpha init_f_ov my_param1 my_param2 my_param3
654 0.81543178 1.35000000 0.27000000 0.21000000 1.76000000 0.01000000 0.00000000 0.00000000 0.00000000
```

then set the column numbers like this:

```
file_column_for_param(1) = 3
file_column_for_param(2) = 4
file_column_for_param(3) = 5
file_column_for_param(4) = 6
file_column_for_param(5) = 7
file_column_for_param(6) = 8
file_column_for_param(7) = 9
file_column_for_param(8) = 10
```

Note that if you are not varying one of the parameters, e.g. `f_ov`

,
then you don’t need to set the `file_column`

for that parameter.

### from_file_output_filename

Filename for the `from_file`

output.

```
from_file_output_filename = 'from_file_results.data'
```

## Parameters

You can set a large number of parameters (currently up to 100) that will be
searched/optimized for a best-fitting solution. Specify the
parameters by the name, then either implement your own
parameters in the `set_param`

subroutine in
`run_star_extras.f90`

, or rely on the default
implementation, which provides the legacy options
* `initial_mass`

* `initial_Y`

* `initial_FeH`

* `alpha`

* `f_ov`

### param_name

Names for parameters that will searched/optimized. Empty names `''`

are ignored.

```
param_name(:) = ''
```

### vary_param

If `.true.`

, that parameter will be varied by the search.
If `.false.`

, that parameter will be fixed at the first value
(see `first_param`

).

vary_param(:) = .false.

### first_param

Initial parameter values for parameters that vary; fixed values for parameters that don’t.

```
first_param(:) = 0
```

### min_param

### max_param

Lower and upper bounds for parameter values.

```
min_param(:) = 0
max_param(:) = 0
```

### delta_param

Grid spacing for parameter values, used when `search_type = 'scan_grid'`

.

```
delta_param(:) = 0
```

### Y_depends_on_Z

### Y0

### dYdZ

Legacy controls from the old interface, which is available with
the default `run_star_extras.f90`

by using the parameter names
`initial_Y`

and ``initial_FeH`.

If `Y_depends_on_Z = .false.`

, `Y`

is a parameter like any other and you should set
`vary_Y`

, `first_Y`

, `min_Y`

and `max_Y`

(and `delta_Y`

for a grid).
If `.true.`

, `Y`

depends on `Z`

according to

```
Y = Y0 + dYdZ*Z
```

where `Y0`

and `dYdZ`

are set below.

```
Y_depends_on_Z = .false.
Y0 = 0.248d0
dYdZ = 1.4d0
```

### Y_frac_he3

If using the legacy `initial_Y`

parameter, this controls the
proportion of the initial helium abundance that’s ³He rather than
⁴He.

```
Y_frac_he3 = 1d-4 ! = xhe3/(xhe3 + xhe4); Y = xhe3 + xhe4
```

### f0_ov_div_f_ov

If using the legacy parameter `f_ov`

, the overshoot `f0`

is
changed along with overshoot `f`

according to

```
f0_ov = f0_ov_div_f_ov * f_ov
```

so this must be set to a positive value if `f_ov`

is not zero.

```
f0_ov_div_f_ov = -1
```

## Parameter limits

Calculating mode frequencies is a relatively costly process, so we don’t want to do it for models that are not good candidates. i.e., we want to filter out the bad candidates using the following less expensive tests whenever possible.

Note that if none of the models in a run pass these tests, then you will not get a total \(\chi^2\) result for that run. That might not matter but if you are eliminating too many candidates in this way, the search routines might not get enough valid results to work properly. So watch what you are doing! If your search or scan is getting lots of runs that fail to give \(\chi^2\) results, you’ll need to adjust the limits.

### min_age_limit

Don’t consider models that aren’t old enough.

```
min_age_limit = 1d6
```

### Lnuc_div_L_limit

Don’t consider models with L_nuc/L less than this limit. This rules out pre-ZAMS models.

```
Lnuc_div_L_limit = 0.95
```

### chi2_spectroscopic_limit

Don’t consider models with `chi2_spectro`

above this limit.

```
chi2_spectroscopic_limit = 1000
```

### chi2_delta_nu_limit

Don’t consider models with `chi2_delta_nu`

above this limit.

```
chi2_delta_nu_limit = 1000
```

### chi2_radial_limit

We only calculate radial modes if the previous checks pass.

Calculating non-radial modes is much more expensive than radial ones, so we skip the non-radial calculation if the radial results are poor.

Don’t consider models with `chi2_radial`

above this limit.

```
chi2_radial_limit = 100
```

We only calculate full \(\chi^2\) if the model passes all these limit checks.

## Timestep adjustment

We don’t want to evaluate more models than we need to but we also want to make sure that we resolve the optimal \(\chi^2\). These controls adjust the maximum timestep depending on how close we are to the target values.

If you set the timestep limits too large, you run the risk of missing good \(\chi^2\) cases. But if they are very small, you will spend a lot of runtime calculating lots of frequencies for lots of models. There is no standard set of best values for this. The choice will depend on the stage of evolution and how fast things are changing in the general region of the models with good \(\chi^2\) values. These are just default values: there is no alternative to trying things and tuning the controls for your problem.

### max_yrs_dt_when_cold

```
max_yrs_dt_when_cold = 1d8 ! when fail Lnuc/L, chi2_spectro, or ch2_delta_nu
```

### max_yrs_dt_when_warm

```
max_yrs_dt_when_warm = 1d7 ! when pass previous but fail chi2_radial; < max_yrs_dt_when_cold
```

### max_yrs_dt_when_hot

```
max_yrs_dt_when_hot = 1d6 ! when pass chi2_radial; < max_yrs_dt_when_warm
```

### chi2_limit_for_small_timesteps

```
chi2_limit_for_small_timesteps = -1
```

### max_yrs_dt_chi2_small_limit

```
max_yrs_dt_chi2_small_limit = 3d5 ! < max_yrs_dt_when_hot
```

### chi2_limit_for_smaller_timesteps

```
chi2_limit_for_smaller_timesteps = -1 ! < chi2_limit_for_small_timesteps
```

### max_yrs_dt_chi2_smaller_limit

```
max_yrs_dt_chi2_smaller_limit = 1d5 ! < max_yrs_dt_chi2_small_limit
```

### chi2_limit_for_smallest_timesteps

```
chi2_limit_for_smallest_timesteps = -1 ! < chi2_limit_for_smaller_timesteps
```

### max_yrs_dt_chi2_smallest_limit

```
max_yrs_dt_chi2_smallest_limit = 5d4 ! < max_yrs_dt_chi2_smaller_limit
```

### sigmas_coeff_for_delta_nu_limit

### sigmas_coeff_for_constraint_limit

We need a way to decide when to stop an evolution run.
The following limits are used for this.
We don’t want to stop too soon, so these limits
are only tested for models that are okay for the `Lnuc_div_L_limit`

.

The limit on each variable `X`

is

```
X_limit = X_target + X_sigma*sigmas_coeff_for_X_limit
```

We only use limits where `sigma_coeff_X`

is not zero.
If `sigma_coeff`

is positive, we stop when that value is greater than the limit.
If `sigma_coeff`

is negative, we stop when that value is less than the limit.
Hence, use positive `sigma_coeff`

for values that are increasing (e.g. `log_L`

)
and negative `sigma_coeff`

for values that are decreasing
(e.g. `log_g`

, `Teff`

, `delta_nu`

).

```
sigmas_coeff_for_delta_nu_limit = 0
sigmas_coeff_for_constraint_limit(:) = 0
```

## \(\chi^2\) limits

You can stop the run if \(\chi^2\) is rising.

### limit_num_chi2_too_big

### chi2_relative_increase_limit

If any of the following conditions are met in `limit_num_chi2_too_big`

consecutive models
after a minimum \(\chi^2\) has been found, stop the run for that sample.

\(\chi^2\) is greater than

`chi2_relative_increase_limit`

times the best \(\chi^2\) for the run.`chi2_spectro`

,`chi2_delta_nu`

or`chi2_radial`

is greater than its corresponding`_limit`

.MESA fails to evaluate \(\chi^2\) (because e.g. it can’t match all the modes of a particular degree).

```
limit_num_chi2_too_big = 20
chi2_relative_increase_limit = 2.0
```

### chi2_search_limit1

### chi2_search_limit2

If the best \(\chi^2\) for the run is less than `chi2_search_limit1`

,
stop the run if \(\chi^2\) is greater than `chi2_search_limit2`

.

```
chi2_search_limit1 = 3.0
chi2_search_limit2 = 4.0
```

If you are doing a search or scanning a grid, you can use previous results as a guide for when to stop a run

### min_num_samples_for_avg

### max_num_samples_for_avg

### avg_age_sigma_limit

### avg_model_number_sigma_limit

We can stop the run using limits based on the average age of previous samples.
Specifically, use at least `min_num_samples_for_avg`

and at most
`max_num_samples_for_avg`

to compute the average age and model number,
then stop the run if the age is greater than the average age or model number
plus `avg_age_sigma_limit`

or `avg_model_number_sigma_limit`

times the standard deviation
of the same set of samples.

```
min_num_samples_for_avg = 2 ! want at least this many samples to form averages
max_num_samples_for_avg = 10 ! use this many of the best chi^2 samples for averages
avg_age_sigma_limit = 10 ! stop if age > avg age + this limit times sigma of avg age
avg_model_number_sigma_limit = 10 ! ditto for model number
```

## Surface corrections

### correction_scheme

The options for the correction scheme are:

`'kjeldsen'`

, the correction of Kjeldsen et al. (2008);`'power_law'`

, a free power law, used as a sanity check in Ball & Gizon (2017);`'cubic'`

, the cubic/one-term correction by Ball & Gizon (2014, eqn 3);`'combined'`

, the combined/two-term correction by Ball & Gizon (2014, eq 4);`'sonoi'`

, the modified Lorentzian by Sonoi et al. (2015, eq 9); or`''`

, no corrections.

```
correction_scheme = 'kjeldsen'
```

If you’d like to experiment with your own correction scheme,
you can use the `other_astero_freq_corr`

hook in `$MESA_DIR/star`

.

### surf_coef1_name

### surf_coef2_name

Each surface correction has one or two parameters that are
passed around in the code as `surf_coef1`

and `surf_coef2`

and
reported in the output under the control parameters
`surf_coef1_name`

and `surf_coef2_name`

.
In the various schemes, the surface corrections added to a mode with
frequency \(\nu\), normalized inertia \(\mathcal{I}\)
and relative inertia \(Q\) are

where `νac`

is the acoustic cutoff frequency, computed by
scaling the solar value of 5mHz in the same way as `νmax`

(i.e. `νac = 5mHz * (g/gsun)/sqrt(Teff/Teff_sun)`

).

```
surf_coef1_name = 'a_div_r'
surf_coef2_name = 'correction_r'
```

The default values `a_div_r`

and `correction_r`

correspond to the
behaviour in r11701 and before.

### correction_factor

Scale the correction by this fraction. Set to zero to skip doing corrections.

```
correction_factor = 0
```

### correction_b

Solar-calibrated power law index used in the `kjeldsen`

surface correction.
The `kjeldsen`

surface correction uses the observed radial orders of the
radial modes (`l0_n_obs`

) if they are provided.

```
correction_b = 4.90d0
```

note: to set nu_max_sun or delta_nu_sun, see star/defaults/controls.defaults

output controls

### astero_results_directory

Directory in which to save `astero`

outputs.
If it doesn’t exist, it will be created.

```
astero_results_directory = 'outputs'
```

### astero_results_dbl_format

### astero_results_int_format

### astero_results_txt_format

Formats for writing floats (reals), integers and characters (strings) to the results file.

astero_results_dbl_format = ‘(1pes26.16)’ astero_results_int_format = ‘(i26)’ astero_results_txt_format = ‘(a26)’

### write_best_model_data_for_each_sample

```
write_best_model_data_for_each_sample = .true.
```

### num_digits

Number of digits in sample number (with leading zeros).

```
num_digits = 4
```

### sample_results_prefix

### sample_results_postfix

Prefix and postfix for sample results filenames.

```
sample_results_prefix = 'sample_'
sample_results_postfix = '.data'
```

### model_num_digits

Number of digits in model number (with leading zeros).

```
model_num_digits = 4
```

### write_fgong_for_each_model

```
write_fgong_for_each_model = .false.
```

### fgong_prefix

### fgong_postfix

Prefix and postfix for FGONG filenames. You can include a directory in the prefix if desired but you must create the directory yourself.

```
fgong_prefix = 'fgong_'
fgong_postfix = '.data'
```

### write_fgong_for_best_model

```
write_fgong_for_best_model = .false.
```

### best_model_fgong_filename

```
best_model_fgong_filename = ''
```

### write_gyre_for_each_model

```
write_gyre_for_each_model = .false.
```

### gyre_prefix

### gyre_postfix

Prefix and postfix for GYRE filenames. You can include a directory in the prefix if desired but you must create the directory yourself.

```
gyre_prefix = 'gyre_'
gyre_postfix = '.data'
```

### max_num_gyre_points

```
max_num_gyre_points = -1 ! only used if > 1
```

### write_gyre_for_best_model

```
write_gyre_for_best_model = .false.
```

### best_model_gyre_filename

```
best_model_gyre_filename = ''
```

### write_profile_for_best_model

```
write_profile_for_best_model = .false.
```

### best_model_profile_filename

```
best_model_profile_filename = ''
```

### save_model_for_best_model

```
save_model_for_best_model = .false.
```

### best_model_save_model_filename

```
best_model_save_model_filename = ''
```

### save_info_for_last_model

### last_model_save_info_filename

If `save_info_for_last_model = .true.`

, treat the final model
as the “best” and save info about final model to
`last_model_save_info_filename`

.

```
save_info_for_last_model = .false.
last_model_save_info_filename = '' ! and save info about final model to this file.
```

## Miscellaneous

### save_next_best_at_higher_frequency

### save_next_best_at_lower_frequency

Save info about next best matches.

```
save_next_best_at_higher_frequency = .false.
save_next_best_at_lower_frequency = .false.
```

### trace_limits

If `.true.`

, write info to terminal about status relative to various limits,
e.g. if `sigmas_coeff_for_Teff_limit`

is set,
`Teff_limit = Teff_target + Teff_sigma*sigmas_coeff_for_Teff_limit`

and
the run will stop when `Teff < Teff_limit`

.
Trace will write out values of `Teff`

and `Teff_limit`

.
The same goes for other limits, e.g. `logg`

, `logL`

, `delta_nu`

, etc.

```
trace_limits = .false.
```

### save_controls

### save_controls_filename

If `save_controls = .true.`

, the controls in `&astero_search_controls`

are dumped to the file `save_controls_filename`

.
If `save_controls_filename`

is empty, a default filename is used.

```
save_controls = .false. ! dumps &astero_search_controls controls to file
save_controls_filename = '' ! if empty, uses a default name
```

### save_mode_model_number

### save_mode_filename

### el_to_save

### order_to_save

Save an eigenfunction.

```
save_mode_model_number = 0
save_mode_filename = ''
el_to_save = 0
order_to_save = 0
```

### add_atmosphere

If `.true.`

, then `star`

adds the atmosphere structure
before passing the model to ADIPLS or GYRE.
The atmosphere model is determined by the atmosphere boundary
conditions in the `&controls`

namelist for `star`

.

```
add_atmosphere = .false.
```

### keep_surface_point

If `.true.`

, keep the `k=1`

point of model.

```
keep_surface_point = .false.
```

### add_center_point

If `.true.`

, add a point at `r=0`

.

```
add_center_point = .true.
```

## Oscillation calculation controls

### oscillation_code

Either `'adipls'`

or `'gyre'`

(lower case).

```
oscillation_code = 'adipls'
```

### trace_time_in_oscillation_code

```
trace_time_in_oscillation_code = .false.
```

## GYRE controls

The GYRE controls are read from the `gyre_input_file`

.
Rich offers the following comments on setting them:

> I suggest setting freq_min to 0.9*MINVAL(l0_obs), > and freq_max to 1.1*MAXVAL(l0_obs) > (similarly for the other l values).

> freq_units should be ‘UHZ’, > and set grid_type to ‘LINEAR’.

> For n_freq, I suggest either setting it to 10*(freq_max - freq_min)/dfreq, > where dfreq is the estimated frequency spacing; or, set it to 10*nl0. > The factor 10 is arbitrary, but seems to be a good safety factor.

### gyre_input_file

```
gyre_input_file = 'gyre.in'
```

### gyre_non_ad

```
gyre_non_ad = .false.
```

## ADIPLS controls

Some ADIPLS controls are set here. The rest are set in `adipls.c.pruned.in`

.

ADIPLS looks for frequencies in a given range and with a given “density” of coverage.
For example,
for `l=0`

, the ADIPLS frequency search range is `nu_lower_factor*l0_obs(1)`

to `nu_upper_factor*l0_obs(nl0)`

and it uses `iscan = iscan_factor_l0*nl0`

to determine how fine the scan is over the range.

### do_redistribute_mesh

The number of zones for ADIPLS’ remeshing is set in `redistrb.c.pruned.in`

.
If you set this `.false.`

, then the mesh from `star`

is used directly.
If you set this `.true.`

, then `astero`

calls ADIPLS’s `redistb`

before doing
the frequency analysis.

```
do_redistribute_mesh = .true.
```

### iscan_factor

ADIPLS will scan for frequencies at `iscan_factor(l)`

times the number
of observed `l`

modes.

```
iscan_factor(0) = 15
iscan_factor(1) = 15
iscan_factor(2) = 15
iscan_factor(3) = 15
```

### nu_lower_factor

### nu_upper_factor

The frequency scan range is set from the observed frequencies times these factors.

```
nu_lower_factor = 0.8
nu_upper_factor = 1.2
```

### adipls_irotkr

### adipls_nprtkr

### adipls_igm1kr

### adipls_npgmkr

Miscellaneous ADIPLS parameters for experts.

```
adipls_irotkr = 0
adipls_nprtkr = 0
adipls_igm1kr = 0
adipls_npgmkr = 0
```

## Include other inlists

### read_extra_astero_search_inlist(1..5)

### extra_astero_search_inlist_name(1..5)

If `read_extra_astero_search_inlist(i)`

is `.true.`

, then read the namelist
in file `extra_astero_search_inlist_name(i)`

.

```
read_extra_astero_search_inlist(:) = .false.
extra_astero_search_inlist_name(:) = 'undefined'
```