save_delchi

sherpa.ui.save_delchi(id, filename=None, clobber=False, sep=' ', comment='#', linebreak='\n', format='%g')

Save the ratio of residuals (data-model) to error to a file.

Parameters:

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.
filename (str) – The name of the file to write the array to.
clobber (bool, optional) – If filename is not None, then this flag controls whether an existing file can be overwritten (True) or if it raises an exception (False, the default setting).
sep (str, optional) – The separator character. The default is ' '.
comment (str, optional) – The comment character. The default is '#'.
linebreak (str, optional) – Indicate a new line. The default is '\n'.
format (str, optional) – The format used to write out the numeric values. The default is '%g%'.

Raises:

sherpa.utils.err.IdentifierErr – If no model has been set for this data set.
sherpa.utils.err.IOErr – If filename already exists and clobber is False.

See also

save_data: Save the data to a file.
save_resid: Save the residuals (data-model) to a file.

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 filename parameter. If given two un-named arguments, then they are interpreted as the id and filename parameters, respectively. The remaining parameters are expected to be given as named arguments.

The output file contains the columns X and DELCHI. The residuals array respects any filter setting for the data set.

Examples

Write the residuals to the file “delchi.dat”:

>>> save_delchi('delchi.dat')

Write the residuals from the data set ‘jet’ to the file “delchi.dat”:

>>> save_resid('jet', "delchi.dat", clobber=True)