# thaw¶

sherpa.astro.ui.thaw(*args)

Allow model parameters to be varied during a fit.

If called with no arguments, then all parameters of models in source expressions are thawed. The arguments can be parameters or models (in which case all parameters of the model are thawed).

fit()

Fit one or more data sets.

freeze()

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

link()

Link a parameter value to an associated value.

set_par()

Set the value, limits, or behavior of a model parameter.

unlink()

Notes

The freeze function can be used to reverse this setting, so that parameters are “frozen” and so remain constant during a fit.

Examples

Ensure that the FWHM parameter of the line model (in this case a gauss1d model) will be varied in any fit.

>>> set_source(const1d.bgnd + gauss1d.line)
>>> thaw(line.fwhm)
>>> fit()


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

>>> thaw(line)
>>> fit()


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

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