get_stat_info

sherpa.astro.ui.get_stat_info()

Return the statistic values for the current models.

Calculate the statistic value for each data set, and the combined fit, using the current set of models, parameters, and ranges.

Returns:

stats – The values for each data set. If there are multiple model expressions then the last element will be the value for the combined data sets.

Return type:

array of sherpa.fit.StatInfoResults

See also

calc_stat

Calculate the fit statistic for a data set.

calc_stat_info

Display the statistic values for the current models.

get_fit_results

Return the results of the last fit.

list_data_ids

List the identifiers for the loaded data sets.

list_model_ids

List of all the data sets with a source expression.

Notes

If a fit to a particular data set has not been made, or values - such as parameter settings, the noticed data range, or choice of statistic - have been changed since the last fit, then the results for that data set may not be meaningful and will therefore bias the results for the simultaneous results.

The return value of get_stat_info differs to get_fit_results since it includes values for each data set, individually, rather than just the combined results.

The fields of the object include:

name

The name of the data set, or sets, as a string.

ids

A sequence of the data set ids (it may be a tuple or array) included in the results.

bkg_ids

A sequence of the background data set ids (it may be a tuple or array) included in the results, if any.

statname

The name of the statistic function (as used in set_stat).

statval

The statistic value.

numpoints

The number of bins used in the fits.

dof

The number of degrees of freedom in the fit (the number of bins minus the number of free parameters).

qval

The Q-value (probability) that one would observe the reduced statistic value, or a larger value, if the assumed model is true and the current model parameters are the true parameter values. This will be None if the value can not be calculated with the current statistic (e.g. the Cash statistic).

rstat

The reduced statistic value (the statval field divided by dof). This is not calculated for all statistics.

Examples

>>> res = get_stat_info()
>>> res[0].statval
498.21750663761935
>>> res[0].dof
439