Set the statistical method
The set_stat command sets the statistical method to be used in fitting.
-
stat - the statistical method
Available statistics are returned by the list_stats command
("ahelp list_stats").
There is a help file for each statistical method, e.g.
("ahelp chi2constvar").
| leastsq |
least-squares fitting (chi^2 without statistical errors) |
| chi2constvar |
chi^2 with constant variance computed from the counts
data |
| chi2modvar |
chi^2 with model amplitude
variance |
| chi2gehrels |
chi^2 with gehrels method
(default) |
| chi2datavar |
chi^2 with data variance |
| chi2xspecvar |
chi^2 with data variance (XSPEC-style, variance = 1.0 if
data less than or equal to 0.0). |
| cstat |
CStat - A maximum likelihood function (XSPEC
implementation of Cash) |
| cash |
Cash - A maximum likelihood function |
sherpa> set_stat( "chi2modvar" );
Set the statistic to "chi2modvar", chi^2 with model
amplitude variance.
sherpa> set_stat( "cash" );
Set the statistic to "cash", a maximum likelihood function.
- sl.sherpa
-
cash,
chi2constvar,
chi2datavar,
chi2gehrels,
chi2modvar,
chi2xspecvar,
chisquare,
cstat,
get_par,
image_setregion,
leastsq,
list_stats,
set_analysis,
set_areascal,
set_arf,
set_backscal,
set_bkg,
set_bkg_model,
set_coord,
set_counts,
set_covar_opt,
set_data,
set_default_id,
set_exposure,
set_grouping,
set_method,
set_method_opt,
set_model,
set_par,
set_pileup_model,
set_proj_opt,
set_rmf,
set_source,
set_staterror,
set_syserror
- sl.sherpa_contrib
-
set_param_limits_from_image
|
![[Sherpa Logo]](../imgs/sherpa_logo_navbar.gif){kind=logo}