Last modified: December 2023

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AHELP for CIAO 4.16 Sherpa


Context: confidence


Return the confidence-interval estimation object.




Example 1

>>> print(get_conf())
name         = confidence
numcores     = 8
verbose      = False
openinterval = False
max_rstat    = 3
maxiters     = 200
soft_limits  = False
eps          = 0.01
fast         = False
maxfits      = 5
remin        = 0.01
tol          = 0.2
sigma        = 1
parallel     = True

Example 2

Change the remin field to 0.05.

>>> cf = get_conf()
>>> cf.remin = 0.05


The attributes of the confidence-interval object include:

Item Definition
eps The precision of the calculated limits. The default is 0.01.
fast If True then the fit optimization used may be changed from the current setting (only for the error analysis) to use a faster optimization method. The default is False .
max_rstat If the reduced chi square is larger than this value, do not use (only used with chi-square statistics). The default is 3.
maxfits The maximum number of re-fits allowed (that is, when the remin filter is met). The default is 5.
maxiters The maximum number of iterations allowed when bracketing limits, before stopping for that parameter. The default is 200.
numcores The number of computer cores to use when evaluating results in parallel. This is only used if parallel is True . The default is to use all cores.
openinterval How the `conf` method should cope with intervals that do not converge (that is, when the maxiters limit has been reached). The default is False .
parallel If there is more than one free parameter then the results can be evaluated in parallel, to reduce the time required. The default is True .
remin The minimum difference in statistic value for a new fit location to be considered better than the current best fit (which starts out as the starting location of the fit at the time `conf` is called). The default is 0.01.
sigma What is the error limit being calculated. The default is 1.
soft_limits Should the search be restricted to the soft limits of the parameters ( True ), or can parameter values go out all the way to the hard limits if necessary ( False ). The default is False
tol The tolerance for the fit. The default is 0.2.
verbose Should extra information be displayed during fitting? The default is False .


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

See Also

conf, confidence, covar, covariance, get_conf_opt, get_conf_results, get_covar, get_covar_opt, get_covar_results, get_covariance_results, get_int_proj, get_int_unc, get_proj, get_proj_opt, get_proj_results, get_projection_results, get_reg_proj, get_reg_unc, int_proj, int_unc, proj, projection, reg_proj, reg_unc, set_conf_opt, set_covar_opt, set_proj_opt
get_chart_spectrum, get_marx_spectrum
get_areascal, get_arf, get_arf_plot, get_axes, get_backscal, get_bkg, get_bkg_arf, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_rmf, get_bkg_scale, get_bkg_source, get_bkg_source_plot, get_coord, get_counts, get_data, get_data_contour, get_data_contour_prefs, get_data_image, get_data_plot, get_data_plot_prefs, get_dep, get_dims, get_error, get_exposure, get_grouping, get_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror
calc_stat_info, get_stat_info
get_default_id, list_stats
get_draws, get_iter_method_name, get_iter_method_opt, get_method, get_method_name, get_method_opt
get_model, get_model_component, get_model_component_image, get_model_component_plot, get_model_plot, get_num_par, get_num_par_frozen, get_num_par_thawed, get_order_plot, get_par, get_pileup_model, get_response, get_source, get_source_component_image, get_source_component_plot, get_source_contour, get_source_image, get_source_plot, image_source
get_psf, get_psf_contour, get_psf_image, get_psf_plot
get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat, get_stat_name
get_analysis, get_rate