sherpa.astro.ui.get_syserror(id=None, filter=False, bkg_id=None)

Return the systematic error on the dependent axis of a data set.

The function returns the systematic errors on the values (dependenent axis) of a data set, or its background. It is an error if called on a data set with no systematic errors (which are set with set_syserror).

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

  • filter (bool, optional) – Should the filter attached to the data set be applied to the return value or not. The default is False.

  • bkg_id (int or str, optional) – Set if the values returned should be from the given background component, instead of the source data set.


syserrors – The systematic error for each data point. The size of this array depends on the filter argument.

Return type



See also


Return the errors on the dependent axis of a data set.


Return the independent axis of a data set.


Return the statistical errors on the dependent axis of a data set.


List the identifiers for the loaded data sets.


Set the systematic errors on the dependent axis of a data set.


The default behavior is to not apply any filter defined on the independent axes to the results, so that the return value is for all points (or bins) in the data set. Set the filter argument to True to apply this filter.


Return the systematic error for the default data set:

>>> yerr = get_syserror()

Return an array that has been filtered to match the data:

>>> yerr = get_syserror(filter=True)

Return the filtered errors for data set “core”:

>>> yerr = get_syserror("core", filter=True)