Chandra X-Ray Observatory
	(CXC)
Skip to the navigation links
Last modified: December 2013

URL: http://cxc.harvard.edu/sherpa/ahelp/unlink.html
Jump to: Description · Examples · Bugs · See Also


AHELP for CIAO 4.9 Sherpa v1

unlink

Context: modeling

Synopsis

Remove a link between model parameters

Syntax

unlink( par )

Description

The unlink command removes a link between two model parameters.

  • par - the model parameter to unlink

When a link is removed between two model parameters, the parameter value is set to that of the parameter to which it had been linked. When a link is removed between a model parameter and a model stack, the parameter is set to the value it had before that link was established.

A link between two model parameters is established using the link command ("ahelp link").

Example 1

sherpa> set_source(gauss1d.g1 + gauss1d.g2)
sherpa> link(g1.ampl, 0.5*g2.ampl)
sherpa> show_model()
...
g1.ampl linked 0.5 expr: (0.5 * g2.ampl)

sherpa> unlink(g1.ampl)
sherpa> show_model()
...
g1.ampl thawed 1 -3.4e+38 3.4e+38

Link the amplitudes of two Gaussian models, then remove the link.

Example 2

sherpa> link(modelc.3, 2*modeld.3 - modele.3)
sherpa> unlink(modelc.3)

Create a link to a model expression, then remove the link.

Bugs

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

See Also

contrib
renorm
modeling
freeze, guess, link, paramprompt, set_par, thaw

Last modified: December 2013
Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email:   cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2017. All rights reserved.