Last modified: December 2020

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/get_grouping.html
AHELP for CIAO 4.13 Sherpa v1

get_grouping

Context: data

Synopsis

Return the grouping array for a PHA data set.

Syntax

get_grouping(id=None, bkg_id=None)

id - int or str, optional
bkg_id - int or str, optional

Description

The function returns the grouping value for each channel in the PHA data set.


Examples

Example 1

Copy the grouping array from the default data set to data set 2:

>>> grp1 = get_grouping()
>>> set_grouping(2, grp1)

Example 2

Return the grouping array of the background component labelled 2 for the 'histate' data set:

>>> grp = get_grouping('histate', bkg_id=2)

PARAMETERS

The parameters for this function are:

Parameter Definition
id The identifier for the data set to use. If not given then the default identifier is used, as returned by `get_default_id` .
bkg_id Set if the grouping flags should be taken from a background associated with the data set.

Return value

The return value from this function is:

grouping -- A value of 1 indicates the start of a new group, and -1 indicates that the bin is part of the group. This array is not filtered - that is, there is one element for each channel in the PHA data set. Changes to the elements of this array will change the values in the dataset (it is a reference to the values used to define the quality, not a copy).

Notes

The meaning of the grouping column is taken from [1] , which says that +1 indicates the start of a bin, -1 if the channel is part of group, and 0 if the data grouping is undefined for all channels.

References


Bugs

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

See Also

confidence
get_conf, 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
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_indep, get_quality, get_rmf, get_specresp, get_staterror, get_syserror, group, group_adapt, group_adapt_snr, group_bins, group_counts, group_snr, group_width, load_grouping, set_grouping, ungroup
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
saving
save_grouping
statistics
get_chisqr_plot, get_delchi_plot, get_prior, get_sampler, get_stat, get_stat_name
utilities
get_analysis, get_rate
visualization
image_getregion