Overview of the astero module
Overview of the astero
module
The astero
module serves two basic functions in MESA.

It links to two stellar oscillation packages to compute stellar oscillation frequencies from inside MESA.

It implements algorithms to search for model parameters that best fit some observations (seismic or not).
By design, the astero
module doesn't do much of the first task for
you automatically. Instead, it provides hooks that you can use in
run_star_extras
. So if you want to compute a grid of models with
oscillation frequencies, you can call these routines according to your
needs.
The astero/work
directory presumes that you wish to perform the
second task and most of this tutorial is about how to use MESA and
astero_search_controls
to fit models to data. It's strongly
recommended that you try running the example in work
and make sense
of what the inputs and outputs are. A brief description of the
example is at the end of this document.
Calculating stellar oscillations
MESA provides interfaces to two stellar oscillation codes: ADIPLS and
GYRE. The subroutines for calling these codes is found in
star/astero/src
. So, for example, adipls_support.f
has various
subroutines for calling ADIPLS to compute frequencies. For examples
of how this is done, have a look in astero_support.f
. To use these
routines in run_star_extras
, use
the relevant module in your
own subroutine.
ADIPLS
ADIPLS is wellestablished code, written and maintained by
Jørgen ChristensenDalsgaard. It computes linear, adiabatic
oscillation frequencies using one of a secondorder shooting method,
fourthorder shooting method or relaxation method, with or without
Richardson extrapolation. Detailed documentation is bundled with MESA
in two files, both found in $MESA_DIR/adipls/adipack.c/notes
:

adiab.prg.c.pdf
describes the details of the oscillation calculation, including the control file,adipls.c.in
. 
operation.ps
describes how to use several utility scripts that convert between binary and ASCII formats and remesh the model. If you're only using ADIPLS from inside MESA, you generally don't need to worry about these.
GYRE
GYRE is a new, opensource code, written and maintained by Rich Townsend. GYRE computes linear adiabatic or nonadiabatic oscillation frequencies using a parallelized multiple Magnusson shooting scheme. Like ADIPLS, tThere are multiple options for the formulation of the equations, boundary conditions, order of the integration method, and more. The documentation is online at the GYRE website.
Stellar modelling as an optimization problem
To understand the second task, let's briefly consider a very general problem. Suppose that I have a magical black box that produces some numbers y given some input numbers x. In other words, I have some function y(x) but not its inverse: I can't run the box backwards. Now, suppose that some other kindly soul has gone out and measured some values of y. How do I decide which values of x reproduce y, using my black box? As you can imagine, this is a common problem in science and engineering, known variously as optimization, parameter estimation or occasionally inversion (though the latter usually refers to the case where x is a continuous variable and y(x) a function, rather than a discrete set of paremeters and observations).
Here, our magical black box is MESA (although it's unlocked, so you
can look inside yourself!) and the observations y it produces are
anything about a star that can be observed: effective temperature,
surface gravity, metallicity, radius, mass, mode frequencies,
whatever. The parameters x are the numbers we need to make a
stellar model, like mass, age, mixinglength, and composition. The
astero
module implements some standard algorithms that optimize
the stellar model, given observational constraints. The user can
choose which parameters to vary and which to fix. You can also
constrain the helium abundance and metallicity to vary together
according to some enrichment law.
Although we're discussing the astero
module, this process doesn't
have to involve seismology. We can try to fit a stellar model even if
we don't have any frequency information because we may also have
luminosities, interferometric radii or even dynamical masses. In
fact, this is precisely what MESA does for the Sun. This
distinguishes MESA's current solar calibration from the standard
procedure. Usually, one fixes the mass and age of the Sun and fits
the initial metallicity, initial helium and mixing length to the
observed luminosity, radius and metallicity. MESA uses other
information, including, for example, a direct fit to the rms variation
of the sound speed relative to a reference profile.
Age
MESA capitalizes on the special status of the stellar age. It's special because to have a model at a particular age, you must have the model at the previous age, and the age before that, etc., going all the way back to your initial model. The evaluation of one more model along the current evolutionary track is inexpensive, so it makes sense to optimize the age for every set of trial parameters. Thus, you never need to specify that you want to optimize the age. Rather, you have to specify if you only want to evaluate models at a particular age, as is the case in the solar calibration.
Optimization algorithms
MESA has several optimization algorithms available. They're described here very briefly, so it's recommended that you look up these methods to know exactly what MESA is doing.

Downhill simplex. Constructs a simplex and reflects, expands and contracts it towards a minimum. This is a standard method for functions where reliable derivatives are unavailable. If you don't know where to start, you could do worse than a downhill simplex. Also known as the NelderMead method, and implemented as
amoeba
in IDL andfminsearch
in MATLAB. 
NEWUOA and BOBYQA. Roughly speaking, these two methods approximate the shape of the objective function using quadratic approximation and then use the minimum of the approximation as the next guess for the bestfitting model. These methods are slightly more prone to getting stuck in local minima, so are bettersuited to improving a good fit. BOBYQA is a bounded method, so it respects the maximum and minimum values you provide.
Userdefined searches
MESA can also search for the bestfitting model based on usersupplied data.

Grid search. Evaluates all models at regular intervals in a userspecified range of parameter space.

Input file. Evaluates models with parameters given in a file. Useful for reevaulating models from other runs to get extra output.

No search/optimization. Just runs the userspecified initial parameters. Important during testing, so that you don't lose time to an improperly formulated run. Should also be used if no optimization is desired, but remember to disable the modelfitting specifics like stop conditions and timestep adaptation.
Userdefined observables
MESA allows you to define up to three of your own variables. These
are denoted my_var1
, my_var2
and my_var3
, and included just like
other observables. Their values must be defined in
run_star_extras.f
. An example of your own variables might be the
acoustic depth of the base of the convection zone measured from the
acoustic glitch.
Model inputs
Although astero_search_controls
provides detailed parameters for the
input data, initial guess and progress of the optimization, all the
details about the stellar model (e.g. formulation of mixinglength
theory, opacity tables, etc.) are still contained in the usual
inlist
. Some of these (e.g. the model mass) will be overwritten by
values in astero_search_controls
, but most won't. So don't forget
to check the usual inlist
to make sure you're fitting a model with
the physics you want!
Basic overview of astero_search_controls
structure
In a nutshell, astero_search_controls
contains everything we need to
set up the optimization problem. The components are described in more
detail elsewhere, but the overall structure is given below. Note that
there are some other controls that either don't fit into these
categories or aren't quite in the order given here.

Observational data. These are the numbers we're trying to reproduce. There are several standard options, as well as room to add up to three of your own variables, defined in
run_star_extras.f
. The constraints are separated into seismic and nonseismic and there is an additional control for the relative weights of the two. 
Fitting algorithm. These controls select which optimization algorithm is used and set parameters specific to those methods.

Initial guess and variable parameters. All optimization algorithms require an initial guess. In addition, one must specify which parameters are to be varied and, if using a bounded method, the bounds of the parameter ranges.

Partial evaluation controls. MESA performs some adaptive tricks to avoid calculating everything that's necessary until it's already close to a good fit. For example, computing mode frequencies is more expensive than nonseismic inputs, and nonradial mode frequencies are more expensive that radial mode frequencies.

Stopping conditions. A particular run can be terminated when the fit is becoming much worse or when the stellar model moves outside the bounds of the observations.

Controls for the oscillation codes. The oscillation codes have some options which can be set in MESA. There are always many more that are set in the separate input file, which is specified in this section.

Output. MESA provides options for what output to store.

Other inlists. Finally, like the normal MESA inlist, there is the option to include other inlists. This is very useful if you're performing fits for many stars and want some parameters to remain fixed.
star/astero/work
walkthrough
To concretize this material, let's have a look at the example
contained in the star/astero/work
folder. These are observable
details for the CoRoT target HD49385. Not all the controls are
represented here, so be sure to look at the
star/astero/defaults/astero_search_controls.defaults
too.
Observational data
chi2_seismo_fraction = 0.667d0
This first option specifies that the total reduced chisquared is the some of onethird the nonseismic component and twothirds the seismic component.
include_Teff_in_chi2_spectro = .true.
Teff_target = 6095d0
Teff_sigma = 65d0
include_logg_in_chi2_spectro = .false.
logg_target = 3.97d0
logg_sigma = 0.02d0
include_logL_in_chi2_spectro = .true.
logL_target = 0.67d0
logL_sigma = 0.05d0
include_FeH_in_chi2_spectro = .true. ! [Fe/H]
FeH_target = 0.09
FeH_sigma = 0.05
Z_div_X_solar = 0.02293d0
include_logR_in_chi2_spectro = .false.
logR_target = 0
logR_sigma = 1d4
The list of observational starts with "classical" values. In this case, we have constraints Teff=6095+65K, logg=3.97+0.02, logL=0.67+0.05 and [Fe/H]=0.09+0.05, though the logg constraint is not being used. We must define the solar metallicity to make sense of [Fe/H]. This should be the same as the composition of your stellar model! The option for a radius (e.g. from interferometry) is available but not used here. Keep in mind that, because of the surface boundary condition L=4\pi R^2\sigma Teff^4, constraining R, L and Teff is degenerate.
include_surface_Z_div_X_in_chi2_spectro = .false.
surface_Z_div_X_target = 2.292d2 ! GS98 value
!surface_Z_div_X_target = 1.81d2 ! Asplund 09 value
surface_Z_div_X_sigma = 1d3
include_surface_He_in_chi2_spectro = .false.
surface_He_target = 0.2485d0 ! Bahcall, Serenelli, Basu, 2005
surface_He_sigma = 0.0034
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 = 50 ! only used if > 0
dt_for_smaller_steps_before_age_target = 0.0065d8 ! 1/10 age_sigma
! this should be << age_sigma
include_Rcz_in_chi2_spectro = .false. ! radius of base of convective zone
Rcz_target = 0.713d0 ! Bahcall, Serenelli, Basu, 2005
Rcz_sigma = 1d3
include_csound_rms_in_chi2_spectro = .false. ! check sound profile
csound_rms_target = 0
csound_rms_sigma = 2d6
report_csound_rms = .false.
We then have a series of nonseismic constraints that are principally used in the solar calibration, including a raw value of Z/X, the surface helium abundance, the age target (and controls for meeting it), the depth of the convection zone and the rms difference against a reference sound speed profile.
include_my_var1_in_chi2_spectro = .false.
my_var1_target = 0
my_var1_sigma = 0
my_var1_name = 'my_var1'
include_my_var2_in_chi2_spectro = .false.
my_var2_target = 0
my_var2_sigma = 0
my_var2_name = 'my_var2'
include_my_var3_in_chi2_spectro = .false.
my_var3_target = 0
my_var3_sigma = 0
my_var3_name = 'my_var3'
These controls include userdefined variables. They are computed in
run_star_extras.f
.
chi2_seismo_delta_nu_fraction = 0d0
chi2_seismo_nu_max_fraction = 0d0
chi2_seismo_r_010_fraction = 0d0
chi2_seismo_r_02_fraction = 0d0
We now specify how much of the seismic reduced chisquared comes from the large separation ($\Delta\nu$), the frequency of maximum oscillation power ($\nu_\text{max}$) and the frequency ratios. The remainder of the seismic reduced chisquared comes from the individual mode frequencies.
trace_chi2_seismo_delta_nu_info = .false. ! if true, output info to terminal
trace_chi2_seismo_nu_max_info = .false. ! if true, output info to terminal
trace_chi2_seismo_ratios_info = .false. ! if true, output info to terminal
trace_chi2_seismo_frequencies_info = .false. ! if true, output info to terminal
trace_chi2_spectro_info = .false. ! if true, output info to terminal
These controls provide terminal output about the reduced chisquared calculation.
nu_max = 1010
nu_max_sigma = 1
delta_nu = 56.28
delta_nu_sigma = 1.0
We now set the overall seismic properties. Note that delta_nu
and
delta_nu_sigma
must always be set, even when
chi2_seismo_delta_nu_fraction
is 0. This is because the asymptotic
value of delta_nu
can be evaluated without computing the mode
frequencies.
If delta_nu
in the inlist is positive, then the code uses values for
both delta_nu
and delta_nu_sigma
from the inlist. If delta_nu
is negative in the inlist, the code estimates it by linear fit to the
observed radial frequencies and orders, l0_obs
and l0_n_obs
. If
delta_nu_sigma
from the inlist is also negative, then the code also
sets it by using the radial data.
nl0 = 9
l0_obs(1) = 799.70d0
l0_obs(2) = 855.30d0
l0_obs(3) = 909.92d0
l0_obs(4) = 965.16d0
l0_obs(5) = 1021.81d0
l0_obs(6) = 1078.97d0
l0_obs(7) = 1135.32d0
l0_obs(8) = 1192.12d0
l0_obs(9) = 1250.12d0
l0_obs_sigma(1) = 0.27d0
l0_obs_sigma(2) = 0.73d0
l0_obs_sigma(3) = 0.26d0
l0_obs_sigma(4) = 0.36d0
l0_obs_sigma(5) = 0.28d0
l0_obs_sigma(6) = 0.33d0
l0_obs_sigma(7) = 0.34d0
l0_obs_sigma(8) = 0.45d0
l0_obs_sigma(9) = 0.89d0
nl1 = 10
l1_obs(1) = 748.60d0
l1_obs(2) = 777.91d0
l1_obs(3) = 828.21d0
l1_obs(4) = 881.29d0
l1_obs(5) = 935.90d0
l1_obs(6) = 991.09d0
l1_obs(7) = 1047.79d0
l1_obs(8) = 1104.68d0
l1_obs(9) = 1161.27d0
l1_obs(10) = 1216.95d0
l1_obs_sigma(1) = 0.23d0
l1_obs_sigma(2) = 0.24d0
l1_obs_sigma(3) = 0.42d0
l1_obs_sigma(4) = 0.29d0
l1_obs_sigma(5) = 0.23d0
l1_obs_sigma(6) = 0.22d0
l1_obs_sigma(7) = 0.24d0
l1_obs_sigma(8) = 0.22d0
l1_obs_sigma(9) = 0.33d0
l1_obs_sigma(10) = 0.53d0
nl2 = 8
l2_obs(1) = 794.55d0
l2_obs(2) = 905.31d0
l2_obs(3) = 961.47d0
l2_obs(4) = 1017.56d0
l2_obs(5) = 1075.01d0
l2_obs(6) = 1130.79d0
l2_obs(7) = 1187.55d0
l2_obs(8) = 1246.78d0
l2_obs_sigma(1) = 0.52d0
l2_obs_sigma(2) = 0.35d0
l2_obs_sigma(3) = 0.49d0
l2_obs_sigma(4) = 0.27d0
l2_obs_sigma(5) = 0.27d0
l2_obs_sigma(6) = 0.61d0
l2_obs_sigma(7) = 0.32d0
l2_obs_sigma(8) = 0.84d0
nl3 = 0 ! number of observed l=3 modes
l3_obs(:) = 0 ! frequencies. set l3_obs(1), l3_obs(2) .... l3_obs(nl3)
l3_obs_sigma(:) = 0 ! l3_obs_sigma(i) is uncertainty for l3_obs(i), for i=1,nl3
Finally, we provide the observed frequency data. The number of observed modes of each degree must be provided, but the radial orders are not needed. MESA matches the radial orders on its own. Even so, the order of the radial orders can be set but they are used for other purposes.
Search controls
eval_chi2_at_target_age_only = .false.
True if you only want to evaluate models at a particular target age.
min_age_for_chi2 = 1 ! (years) only use if > 0
max_age_for_chi2 = 1 ! (years) only use if > 0
This confines the search to a range of ages. Chisquared is not evaluated if the age is not within these age bounds.
search_type = 'use_first_values'
This run just uses the first values, since we don't want an example that takes hours upon hours in its default mode. The other options are commented out. Each generally has some tolerance control, a choice of whether or not to resume from a file and a handful of other specific controls.
Choice of parameters
Y_depends_on_Z = .false.
Y0 = 0.248d0
dYdZ = 1.4d0
You may specify that Y varies with Z according do an enrichment law of
the form Y = Y0 + dYdZ*Z
. If you do so, set vary_Y = .false.
below.
vary_FeH = .true. ! FeH = [Fe/H] = log10((Z/X)/Z_div_X_solar)
vary_Y = .true. ! Y the initial uniform value
vary_mass = .true. ! initial mass
vary_alpha = .true.
vary_f_ov = .false.
These controls specify which parameters are free to vary. They are
the initial metallicity, initial helium abundance, mass, mixinglength
parameters alpha
and overshooting parameter f_ov
. Composition
parameters correspond to initial uniform values. The overshooting
parameters sets all the overshooting coefficients (i.e. above and
below all zones, burning or not) to the next trial value.
first_FeH = 0.0118938
first_Y = 0.23765625
first_mass = 1.31093750
first_alpha = 1.5875
first_f_ov = 0.015
min_FeH = 0.012012738
min_Y = 0.2352796875
min_mass = 1.297828125
min_alpha = 1.571625
max_FeH = 0.011774862
max_Y = 0.2400328125
max_mass = 1.324046875
max_alpha = 1.603375
The first
, min
and max
parameters for each parameter control the
initial guess, used for the initialization of the optimization, and
the bounds, for those methods that are bounded. In addition, the
simplex
method uses the bounds to determine the size of the initial
simplex.
delta_FeH = 0.03
delta_Y = 0.01
delta_mass = 0.01
delta_alpha = 0.1
delta_f_ov = 0
These controls specify the spacing in the grid when using the
grid_search
method.
Partial evaluation controls
! 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: if none of the models in a run pass these tests,
! then you will not get any total chi2 result for that run.
! in some situations that might not matter,
! but if you are eliminating too many candidates in this way,
! the search routines might not be getting 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 = 1d6
Lnuc_div_L_limit = 0.95 ! this rules out prezams models
These controls prevent the code from considering premainsequence models.
chi2_spectroscopic_limit = 20
chi2_delta_nu_limit = 20
Models are only considered once the nonseismic reduced chisquared is
less than chi2_spectroscopic_limit
and the chisquared contribution
of the asymptotic large separation is within chi2_delta_nu_limit
.
Note that this means delta_nu
and delta_nu_sigma
must be set, even
if delta_nu
is not included in chisquared.
If these conditions are met
! we calculate radial modes only if pass the previous checks
! calculating nonradial modes is much more expensive than radial ones.
! so we skip the nonradial calculation if the radial results are poor.
! don't consider models with chi2_radial above this limit
chi2_radial_limit = 30
If the previous conditions are met, the radial mode frequencies are
computed. If the chisquared contribution of the radial modes is less
than chi2_radial_limit
, then all the mode frequencies are computed
and chisquared is evaluated in full.
Chisquared based timestep control
max_yrs_dt_when_cold = 1d7 ! when fail Lnuc/L, chi2_spectro, or ch2_delta_nu
max_yrs_dt_when_warm = 1d6 ! when pass previous but fail chi2_radial; < max_yrs_dt_when_cold
max_yrs_dt_when_hot = 1d5 ! when pass chi2_radial; < max_yrs_dt_when_warm
max_yrs_dt_chi2_small_limit = 5d4 ! < max_yrs_dt_when_hot
chi2_limit_for_small_timesteps = 30
max_yrs_dt_chi2_smaller_limit = 5d4 ! < max_yrs_dt_chi2_small_limit
chi2_limit_for_smaller_timesteps = 1d99 ! < chi2_limit_for_small_timesteps
max_yrs_dt_chi2_smallest_limit = 3d4 ! < max_yrs_dt_chi2_smaller_limit
chi2_limit_for_smallest_timesteps = 1d99 ! < chi2_limit_for_smaller_timesteps
These controls set the maximum timestep based on the current value of chisquared. That is, as chisquared becomes smaller, the timestep can be reduced. This is a balancing act between making sure that the age is resolved finely enough to find a good chisquared but not so finely that a lot of time is spent calculating everything even though it isn't improving the fit much.
Stopping conditions
sigmas_coeff_for_logg_limit = 5 ! disable by setting to 0
sigmas_coeff_for_logL_limit = 5 ! disable by setting to 0
sigmas_coeff_for_Teff_limit = 5 ! disable by setting to 0
sigmas_coeff_for_logR_limit = 0 ! disable by setting to 0
sigmas_coeff_for_surface_Z_div_X_limit = 0 ! disable by setting to 0
sigmas_coeff_for_surface_He_limit = 0 ! disable by setting to 0
sigmas_coeff_for_Rcz_limit = 0 ! disable by setting to 0
sigmas_coeff_for_csound_rms_limit = 0 ! disable by setting to 0
sigmas_coeff_for_delta_nu_limit = 0 ! 5 ! disable by setting to 0
sigmas_coeff_for_csound_rms_limit = 0 ! disable by setting to 0
sigmas_coeff_for_my_var1_limit = 0 ! disable by setting to 0
sigmas_coeff_for_my_var2_limit = 0 ! disable by setting to 0
sigmas_coeff_for_my_var3_limit = 0 ! disable by setting to 0
These controls stop the current run when the given observable differs
from its observed value by sigmas_coeff_for_observable_limit
. They
are only used if nonzero. If negative, the limit is a lower limit;
if positive, as an upper limit.
chi2_relative_increase_limit = 2.0
limit_num_chi2_too_big = 3
! and here is an absolute limit
chi2_search_limit1 = 3.0
chi2_search_limit2 = 4.0
! if best chi2 for the run is <= chi2_search_limit1,
! then stop the run if chi2 >= chi2_search_limit2.
The run is halted if limit_num_chi2_too_big
consecutive chisquareds
are more than chi2_relative_increase_limit
times the best chi2 for
the run.
! 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 = 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 = 5 ! stop if age > avg age + this limit times sigma of avg age
avg_model_number_sigma_limit = 5 ! ditto for model number
These controls allow you to halt the run if the age is getting much
larger than that of some average of the bestfitting models so far.
Specifically, the means and standard deviations of the age and model
number of at least min_num_samples_for_avg
and at most
max_num_samples_for_avg
are computed. If the age or model number
are greater by more than avg_age_sigma_limit
or
avg_model_number_sigma_limit
, the run is halted. The idea here is
that if the 10 bestfitting models have an average age of 1+0.1 Gyr,
it doesn't make sense to follow a model past, say, 1.5 Gyr.
Surface corrections
! surface corrections (see K08  ApJ 683, pg 175) correction_factor = 1 ! use this fraction of the correction; set to 0 to skip doing corrections. l0_n_obs(:) = 1 ! the observed radial orders (ignored if < 0) ! the observed radial orders are used in calculating surface corrections ! if <= 0, use default calculation for radial orders correction_b = 4.25d0
Output controls
write_best_model_data_for_each_sample = .true.
num_digits = 4 ! number of digits in sample number (with leading 0's)
sample_results_prefix = 'outputs/sample_'
! note that you can include a directory in the prefix if desired
sample_results_postfix = '.data'
model_num_digits = 4 ! number of digits in model number (with leading 0's)
write_fgong_for_each_model = .false.
fgong_prefix = 'fgong_'
! note that you can include a directory in the prefix if desired
fgong_postfix = '.data'
write_fgong_for_best_model = .false.
best_model_fgong_filename = ''
write_gyre_for_each_model = .false.
gyre_prefix = 'gyre_'
! note that you can include a directory in the prefix if desired
gyre_postfix = '.data'
max_num_gyre_points = 1 ! only used if > 1
write_gyre_for_best_model = .false.
best_model_gyre_filename = ''
write_profile_for_best_model = .false.
best_model_profile_filename = ''
save_model_for_best_model = .false.
best_model_save_model_filename = ''
save_info_for_last_model = .false. ! if true, treat final model as "best"
last_model_save_info_filename = '' ! and save info about final model to this file.
The controls for recording models and profiles are selfexplanatory.
Options include writing model files, profiles, and inputs for ADIPLS
and GYRE (if you wish to run those codes manually later). The
best_model_data
is a short summary of the parameters of the best
model in that run, similar to output given in the terminal.
The best
model is always the best model of the most recent run.
Thus, at the end of the optimization, these models might not
correspond to the optimal model (though they should be close). You
can save the best models from each run using the scripting option
below.
shell_script_for_each_sample = '' ! executed after at end of sample run
shell_script_num_string_char = '#' ! replace by num string for sample
The shell script specified by shell_script_for_each_sample
will be
evaluated after a run, with shell_script_num_string_char
substituted
by the current sample number. This script can be a single shell
script or a sequence of commands, as long as it works properly as a
oneliner. e.g. cp best.mod outputs/sample#_best.mod; cp
LOGS/history.data outputs/sample#_history.data
Miscellaneous
! save all control settings to file
save_controls = .false. ! dumps &astero_search_controls controls to file
save_controls_filename = '' ! if empty, uses a default name
Saves the control settings (i.e. &astero_search_controls
) to the
specified file.
Y_frac_he3 = 1d4 ! = xhe3/(xhe3 + xhe4); Y = xhe3 + xhe4
Specifies the fractional abundance of helium3 relative to helium4.
Controls for oscillation codes.
save_mode_model_number = 0
save_mode_filename = ''
el_to_save = 0
order_to_save = 0
You can use these controls to save an eigenfunction. If you want a more output, you can compute eigenfunction yourself using the model output and oscillation codes.
add_atmosphere = .false.
If true, then the atmosphere is added to the stellar model before it
is passed to the oscillation code. The atmosphere model is determined
by the control which_atm_option
in &controls
. It should be one of
the T(tau) integration options or Paczynski_grey
, which takes into
account radiation dilution when tau < 2/3,
keep_surface_point = .false.
If true, the surface point of the stellar model is included when the model is passed to the oscillation code.
add_center_point = .true.
As above, but for the centre point.
oscillation_code = 'adipls' ! or 'gyre' <<< lowercase
trace_time_in_oscillation_code = .false.
Selects the oscillation code and specifies whether to report how much time is spent computing the frequencies.
GYRE controls
gyre_l0_input_file = 'gyre.l0.in'
gyre_l1_input_file = 'gyre.l1.in'
gyre_l2_input_file = 'gyre.l2.in'
gyre_l3_input_file = 'gyre.l3.in'
These specify the input files for GYRE, for each degree.
! comments from Rich on setting gyre controls
! 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.
ADIPLS controls
do_redistribute_mesh = .false.
If true, the stellar model will be remeshed according to the settings
in redistrb.c.pruned.in
.
iscan_factor_l0 = 15
iscan_factor_l1 = 15
iscan_factor_l2 = 15
iscan_factor_l3 = 15
nu_lower_factor = 0.8
nu_upper_factor = 1.2
ADIPLS looks for frequencies in a given range and with a given density
of coverage. For example, for l=0, the frequency search range is
nu_lower_factor*l0_obs(1)
to nu_upper_factor*l0_obs(nl0)
and
ADIPLS uses iscan = iscan_factor_l0*nl0
, where iscan
is the number
of scan points in the frequency range. The same applies for the
higher degree modes.
adipls_irotkr = 0
adipls_nprtkr = 0
adipls_igm1kr = 0
adipls_npgmkr = 0
These are a handful of extra controls that are passed to ADIPLS. Look them up in the ADIPLS documentation.
Other inlists
read_extra_astero_search_inlist1 = .false.
extra_astero_search_inlist1_name = 'undefined'
read_extra_astero_search_inlist2 = .false.
extra_astero_search_inlist2_name = 'undefined'
read_extra_astero_search_inlist3 = .false.
extra_astero_search_inlist3_name = 'undefined'
read_extra_astero_search_inlist4 = .false.
extra_astero_search_inlist4_name = 'undefined'
read_extra_astero_search_inlist5 = .false.
extra_astero_search_inlist5_name = 'undefined'
Finally, like all MESA inlists, there are controls to read other
astero_search_control
inlists. This is useful if you're trying to
fitting multiple stars with similar optimization parameters.