plot_resid

sherpa.astro.ui.plot_resid(id=None, replot=False, overplot=False, clearwindow=True, **kwargs)

Plot the residuals (data - model) for a data set.

This function displays the residuals (data - model) for a data set.

Changed in version 4.12.0: The Y axis is now always drawn using a linear scale.

Parameters
  • id (int or str, optional) – The data set. If not given then the default identifier is used, as returned by get_default_id.

  • replot (bool, optional) – Set to True to use the values calculated by the last call to plot_resid. The default is False.

  • overplot (bool, optional) – If True then add the data to an exsiting plot, otherwise create a new plot. The default is False.

  • clearwindow (bool, optional) – Should the existing plot area be cleared before creating this new plot (e.g. for multi-panel plots)?

Raises

sherpa.utils.err.IdentifierErr – If the data set does not exist or a source expression has not been set.

See also

get_resid_plot()

Return the data used by plot_resid.

get_default_id()

Return the default data set identifier.

plot()

Create one or more plot types.

plot_chisqr()

Plot the chi-squared value for each point in a data set.

plot_delchi()

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

plot_ratio()

Plot the ratio of data to model for a data set.

set_xlinear()

New plots will display a linear X axis.

set_xlog()

New plots will display a logarithmically-scaled X axis.

Notes

The additional arguments supported by plot_resid 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.

Examples

Plot the residuals for the default data set:

>>> plot_resid()

Overplot the residuals from the ‘core’ data set on those from the ‘jet’ dataset:

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

Add the residuals to the plot of the data, for the default data set:

>>> plot_data()
>>> plot_resid(overplot=True)

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 the cap length for the ends of the error bars:

>>> plot_resid(capsize=5)