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Last modified: December 2013

URL: http://cxc.harvard.edu/sherpa/ahelp/list_stats.html
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AHELP for CIAO 4.6 Sherpa v1

list_stats

Context: info

Synopsis

List all Sherpa fit statistics.

Syntax

list_stats()

Description

Sherpa includes several different fit statistics that can be used to evaluate how well a model fits a data set. This function lists all statistics, by name; it accepts no arguments.

Available statistics include

  • leastsq: least-squares fitting (chi-square without statistical errors)
  • chi2constvar: chi-square with constant variance computed from the counts data.
  • chi2modvar: chi-square with model amplitude variance.
  • chi2gehrels: chi-square with gehrels method (Sherpa default).
  • chi2datavar: chi-square with data variance.
  • chi2xspecvar: chi-square with data variance (XSPEC-style, variance = 1.0 if data less than or equal to 0.0).
  • cstat: a maximum likelihood function (XSPEC implementation of Cash)
  • cash: a maximum likelihood function.

Example

sherpa> list_stats()

['leastsq', 'chi2constvar', 'chi2modvar', 'cash', 'chi2gehrels', 'chi2datavar', 'chi2xspecvar', 'cstat']

This function returns a list of all Sherpa fit statistics, by name.

Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

confidence
get_conf, get_covar, get_int_proj, get_int_unc, get_proj, get_reg_proj, get_reg_unc
contrib
get_chart_spectrum
data
get_areascal, get_arf, get_arf_plot, get_axes, get_backscal, get_bkg, get_bkg_plot, get_bkg_scale, get_coord, get_counts, get_data, get_data_plot, get_dep, get_dims, get_error, get_exposure, get_grouping, get_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror
filtering
get_filter
fitting
calc_stat_info, get_fit, get_stat_info
info
get_default_id
methods
get_draws, get_iter_method_name, get_iter_method_opt, get_method
modeling
get_model, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_order_plot, get_par, get_pileup_model, get_response, get_source, get_source_component_image, get_source_component_plot, image_source
plotting
get_split_plot
psfs
get_kernel, get_psf
statistics
cash, chi2constvar, chi2datavar, chi2gehrels, chi2modvar, chi2xspecvar, chisquare, cstat, get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat, leastsq, list_priors, set_prior, set_sampler, set_stat
utilities
get_analysis, get_rate
visualization
get_ratio, get_resid, image_getregion

Last modified: December 2013
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