Removes a link between model parameters.
The command-line argument <arg> may be:
UNLINK Command Argument
| <sherpa_modelname>.{<paramname> | <#>} |
A specified model component parameter (e.g., GAUSS.pos). |
| <modelname>.{<paramname> | <#>} |
A specified model component parameter (e.g., g.pos). |
A link between two model parameters is established using the
=> operator (see examples, below); UNLINK
breaks the link.
When a link is removed between model parameters, the parameter value
will be 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
value will return to its value before such a link was established.
Set up, and then remove, a link between model parameters:
sherpa> ERASE ALL
sherpa> PARAMPROMPT ON
Model parameter prompting is on
sherpa> GAUSS[modelb]
modelb.fwhm parameter value [10]
modelb.pos parameter value [0]
modelb.ampl parameter value [1]
sherpa> GAUSS[modelf]
modelf.fwhm parameter value [10]
modelf.pos parameter value [0]
modelf.ampl parameter value [1]
sherpa> modelf.ampl => 0.5*modelb.ampl
The last command in this series uses a model parameter expression,
to link the ampl parameter of modelf
to 0.5 multiplied by the ampl parameter of modelb.
That is, the amplitudes of two Gaussian models are linked, where
one is half that of the other.
Note that model parameter expressions cannot be created
within the model parameter prompting.
The link may be broken as follows:
sherpa> UNLINK modelf.ampl
Set up, and then remove, links between model parameters:
sherpa> PARAMPROMPT OFF
Model parameter prompting is off
sherpa> POW[modelc]
sherpa> POW[modeld]
sherpa> POW[modele]
sherpa> modelc.1 => modele.1
sherpa> modelc.3 => 2*modeld.3 - modele.3
The next-to last command in this series links the
first parameter (gamma) of modelc
to the first parameter of modele.
The last command in this series links the
third parameter (ampl) of modelc
to the parameter expression: 2 multiplied
by the third parameter of modeld,
minus the third parameter of modele.
The links may be broken as follows:
sherpa> UNLINK modelc.1
sherpa> UNLINK modelc.3
- sherpa
-
autoest,
background,
create,
create_model,
createparamset,
fit,
freeze,
get_defined_models,
get_model_params,
get_models,
get_num_par,
get_par,
get_stackexpr,
getx,
gety,
guess,
instrument,
integrate,
is_paramset,
jointmode,
kernel,
lineid,
linkparam,
mdl,
modelexpr,
modelstack,
nestedmodel,
noise,
paramprompt,
paramset,
pileup,
rename,
run_fit,
set_par,
set_paramset,
set_stackexpr,
source,
thaw,
truncate
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