get_covariance_results

Synopsis

Return the results of the last covar run.

Syntax

get_covariance_results()

Alias: get_covar_results

Examples

Example 1

>>> res = get_covar_results()
>>> print(res)
datasets    = (1,)
methodname  = covariance
iterfitname = none
fitname     = levmar
statname    = chi2gehrels
sigma       = 1
percent     = 68.2689492137
parnames    = ('bgnd.c0',)
parvals     = (10.228675427602724,)
parmins     = (-2.4896739438296795,)
parmaxes    = (2.4896739438296795,)
nfits       = 0

Example 2

In this case, of a single parameter, the covariance matrix is just the variance of the parameter:

>>> res.extra_output
array([[ 6.19847635]])

Notes

The fields of the object include:

Item	Definition
datasets	A tuple of the data sets used in the analysis.
methodname	This will be 'covariance'.
iterfitname	The name of the iterated-fit method used, if any.
fitname	The name of the optimization method used.
statname	The name of the fit statistic used.
sigma	The sigma value used to calculate the confidence intervals.
percent	The percentage of the signal contained within the confidence intervals (calculated from the sigma value assuming a normal distribution).
parnames	A tuple of the parameter names included in the analysis.
parvals	A tuple of the best-fit parameter values, in the same order as parnames .
parmins	A tuple of the lower error bounds, in the same order as parnames .
parmaxes	A tuple of the upper error bounds, in the same order as parnames .
nfits	The number of model evaluations.

There is also an extra_output field which is used to return the covariance matrix.

Bugs

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

confidence: conf, confidence, covar, covariance, get_conf, get_conf_results, get_covar, get_covar_opt, get_covar_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
contrib: get_chart_spectrum, get_marx_spectrum
data: 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
filtering: get_filter
fitting: calc_stat_info, get_stat_info
info: get_default_id, list_stats
methods: get_draws, get_iter_method_name, get_iter_method_opt, get_method, get_method_name, get_method_opt
modeling: 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
plotting: get_split_plot
psfs: get_psf, get_psf_contour, get_psf_image, get_psf_plot
statistics: get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat, get_stat_name
utilities: get_analysis, get_rate
visualization: image_getregion

/ sherpa4.16 / ahelp / get_covariance_results.html