Synopsis
Fix model parameters so they are not changed by a fit.
Syntax
freeze(*args)
Description
If called with no arguments, then all parameters of models in source expressions are frozen. The arguments can be parameters or models (in which case all parameters of the model are frozen).
Examples
Example 1
Fix the FWHM parameter of the line model (in this case a `gauss1d` model) so that it will not be varied in the fit.
>>> set_source(const1d.bgnd + gauss1d.line) >>> line.fwhm = 2.1 >>> freeze(line.fwhm) >>> fit()
Example 2
Freeze all parameters of the line model and then re-fit:
>>> freeze(line) >>> fit()
Example 3
Freeze the nh parameter of the gal model and the abund parameter of the src model:
>>> freeze(gal.nh, src.abund)
Notes
The `thaw` function can be used to reverse this setting, so that parameters can be varied in a fit.
Bugs
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.