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Last modified: December 2010

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AHELP for CIAO 4.3 Sherpa v1


Context: data


Return the systematic errors on the counts of a data set


get_syserror( [id, filter=False, bkg_id] )


The get_syserror() function returns the systematic errors on the counts of a source or background data set, by data id or bkg_id. If a data filter has been applied to the data set in question, e.g. ignore() or notice(), the systematic error array for either the filtered or unfiltered data set may be returned by setting the 'filter' argument to 'True' or 'False'. If set to 'True', the systematic error array returned by get_syserror() will be filtered, i.e. the array will be shorter in length than the unfiltered array (not padded with zeros). The systematic errors may be defined by the user with set_syserror().

  • id - the id of the data set to use; if not given, uses the default dataset id (id=1 by default, see "ahelp get_default_id")
  • filter - apply an established data filter to the data set before returning results; default=False
  • bkg_id - the id of the background to use, e.g. if more than one background is associated with the data; default is the first background data set loaded

Example 1

sherpa> get_syserror()

When called with no arguments, the get_syserror() function returns the systematic error array of the unfiltered default data set.

sherpa> print(get_syserror())

Example 2

sherpa> get_syserror(1, bkg_id=1)

To return the systematic error array of a background associated with a data set, the background ID must be specified along with the data set ID. Here, the systematic error array for the first background loaded for data set 1 is returned by get_syserror().

sherpa> print(get_syserror(1, 1))         

Example 3

sherpa> get_syserror(1, filter=True)

If a data set ID is supplied to get_syserror(), the unfiltered systematic error array of the specified data set is returned, unless the 'filter' argument is set to 'True'.


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

See Also

get_conf, get_covar, get_int_proj, get_int_unc, get_proj, get_reg_proj, get_reg_unc
copy_data, dataspace1d, dataspace2d, delete_data, fake, 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, group_sherpa, load_ascii, load_data, load_grouping, load_quality, set_data, set_quality, ungroup, unpack_ascii, unpack_data
get_filter, load_filter, set_filter
calc_stat_info, get_fit, get_stat_info
get_default_id, list_data_ids, list_response_ids, list_stats
get_iter_method_name, get_iter_method_opt, get_method
clean, 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
get_split_plot, plot_data, set_xlinear, set_xlog, set_ylinear, set_ylog
get_kernel, get_psf
save_error, save_filter, save_grouping, save_quality, save_staterror, save_syserror
get_chisqr_plot, get_delchi_plot, get_stat
calc_data_sum, calc_data_sum2d, calc_ftest, calc_kcorr, calc_mlr, calc_model_sum2d, calc_source_sum2d, get_analysis, get_rate
contour, contour_data, contour_ratio, get_ratio, get_resid, histogram1d, histogram2d, image_data, image_getregion, rebin

Last modified: December 2010
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