freeze

Context: modeling

Synopsis

Fix model parameters so they are not changed by a fit.

freeze(*args)

args - sequence of str or Parameter or Model

The arguments can be parameters or models, in which case all parameters of the model are frozen. If no arguments are given then nothing is changed.

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()

Freeze all parameters of the line model and then re-fit:

>>> freeze(line)
>>> fit()

Freeze the nh parameter of the gal model and the abund parameter of the src model:

>>> freeze(gal.nh, src.abund)

The parameter for this function is:

Parameter	Definition
args	The parameters or models to freeze.

The `thaw` function can be used to reverse this setting, so that parameters can be varied in a fit.

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.