plot_ratio¶

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

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

This function displays the ratio data / model for a data set.

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_ratio. 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_ratio_plot(): Return the data used by plot_ratio.
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_resid(): Plot the residuals (data - 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.
set_ylinear(): New plots will display a linear Y axis.
set_ylog(): New plots will display a logarithmically-scaled Y axis.

Notes

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

Examples

Plot the ratio of data to model for the default data set:

>>> plot_ratio()

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

>>> plot_ratio('jet')
>>> plot_ratio('core', 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 X axis to a log scale and draws a solid line between the points:

>>> plot_ratio(xlog=True, linestyle='solid')