Synopsis
Set the statistical errors on the dependent axis of a data set.
Syntax
set_staterror(id, val=None, fractional=False, bkg_id=None) id - int or str, optional val - array or scalar fractional - bool, optional bkg_id - int or str, optional
Description
These values over-ride the errors calculated by any statistic, such as chi2gehrels or chi2datavar .
Examples
Example 1
Set the statistical error for the default data set to the value in dys (a scalar or an array):
>>> set_staterror(dys)
Example 2
Set the statistical error on the 'core' data set to be 5% of the data values:
>>> set_staterror('core', 0.05, fractional=True)
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` . |
val | The systematic error. |
fractional | If False (the default value), then the `val` parameter is the absolute value, otherwise the `val` parameter represents the fractional error, so the absolute value is calculated as get_dep() * val (and `val` must be a scalar). |
bkg_id | Set to identify which background component to set. The default value ( none ) means that this is for the source component of the data set. |
Notes
The function does not follow the normal Python standards for parameter use, since it is designed for easy interactive use. When called with a single un-named argument, it is taken to be the `val` parameter. If given two un-named arguments, then they are interpreted as the `id` and `val` parameters, respectively.
Bugs
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.
See Also
- confidence
- set_conf_opt, set_covar_opt, set_proj_opt
- data
- load_staterror, set_areascal, set_arf, set_backscal, set_bkg, set_coord, set_counts, set_data, set_dep, set_exposure, set_grouping, set_quality, set_rmf, set_syserror
- filtering
- set_filter
- methods
- set_iter_method, set_iter_method_opt, set_method, set_method_opt
- modeling
- get_par, get_xsabund, get_xscosmo, get_xsxsect, get_xsxset, set_bkg_model, set_bkg_source, set_full_model, set_model, set_par, set_pileup_model, set_source, set_xsabund, set_xscosmo, set_xsxsect, set_xsxset
- statistics
- set_prior, set_sampler, set_sampler_opt, set_stat
- utilities
- set_analysis, set_default_id
- visualization
- image_setregion