Last modified: December 2020

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

plot_delchi

Context: plotting

Synopsis

Plot the ratio of residuals to error for a data set.

Syntax

plot_delchi(id=None, replot=False, overplot=False, clearwindow=True,
**kwargs)

id - int or str, optional
replot - bool, optional
overplot - bool, optional
clearwindow - bool, optional

Description

This function displays the residuals (data - model) divided by the error, for a data set.


Examples

Example 1

Plot the residuals for the default data set, divided by the error value for each bin:

>>> plot_delchi()

Example 2

Overplot the values from the 'core' data set on those from the 'jet' dataset:

>>> plot_delchi('jet')
>>> plot_delchi('core', overplot=True)

Example 3

Additional arguments can be given that are passed to the plot backend: the supported arguments match the keywords of the dictionary returned by `get_data_plot_prefs` . The following sets error bars to be orange and the marker to be a circle (larger than the default one):

>>> plot_delchi(ecolor='orange', marker='o')

PARAMETERS

The parameters for this function are:

Parameter Definition
id The data set. If not given then the default identifier is used, as returned by `get_default_id` .
replot Set to True to use the values calculated by the last call to `plot_delchi` . The default is False .
overplot If True then add the data to an existing plot, otherwise create a new plot. The default is False .
clearwindow Should the existing plot area be cleared before creating this new plot (e.g. for multi-panel plots)?

Notes

The additional arguments supported by `plot_delchi` are the same as the keywords of the dictionary returned by `get_data_plot_prefs` .

The ylog setting is ignored, and the Y axis is drawn using a linear scale.

Changes in CIAO

Changed in CIAO 4.12

The Y axis is now always drawn using a linear scale.


Bugs

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

See Also

contrib
get_data_prof, get_data_prof_prefs, get_delchi_prof, get_delchi_prof_prefs, get_fit_prof, get_model_prof, get_model_prof_prefs, get_resid_prof, get_resid_prof_prefs, get_source_prof, get_source_prof_prefs, plot_chart_spectrum, plot_marx_spectrum, prof_data, prof_delchi, prof_fit, prof_fit_delchi, prof_fit_resid, prof_model, prof_resid, prof_source
data
get_arf_plot, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_source_plot
modeling
normal_sample, t_sample, uniform_sample
plotting
get_cdf_plot, get_energy_flux_hist, get_pdf_plot, get_photon_flux_hist, get_pvalue_plot, get_pvalue_results, get_split_plot, plot, plot_arf, plot_bkg, plot_bkg_chisqr, plot_bkg_delchi, plot_bkg_fit, plot_bkg_fit_delchi, plot_bkg_fit_resid, plot_bkg_model, plot_bkg_ratio, plot_bkg_resid, plot_bkg_source, plot_cdf, plot_chisqr, plot_data, plot_energy_flux, plot_fit, plot_fit_delchi, plot_fit_resid, plot_model, plot_model_component, plot_order, plot_pdf, plot_photon_flux, plot_pvalue, plot_ratio, plot_resid, plot_scatter, plot_source, plot_source_component, plot_trace, set_xlinear, set_xlog, set_ylinear, set_ylog
psfs
plot_kernel
statistics
get_chisqr_plot, get_delchi_plot
visualization
contour_resid