Last modified: December 2023

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AHELP for CIAO 4.16 Sherpa


Context: modeling


Should the user be asked for the parameter values when creating a model?



val - bool, optional


When `val` is True , calls to `set_model` will cause the user to be prompted for each parameter in the expression. The prompt includes the parameter name and default value, in [] : the valid responses are

The value , min , and max components are optional, so ",-5" will use the default parameter value and set its minimum to -5, while "2,,10" will change the parameter value to 2 and its maximum to 10, but leave the minimum at its default. If any value is invalid then the parameter is re-prompted.


In the following, the default parameter settings are accepted for the pl.gamma parameter, the starting values for the pl.ref and gline.pos values are changed, the starting value and ranges of both the pl.ampl and gline.ampl parameters are set, and the gline.fwhm parameter is set to 100, with its maximum changed to 10000.

>>> paramprompt(True)
>>> set_source( + gauss1d.gline)
pl.gamma parameter value [1]
pl.ref parameter value [1] 4500
pl.ampl parameter value [1] 1.0e-5,1.0e-8,0.01
gline.fwhm parameter value [10] 100,,10000
gline.pos parameter value [0] 4900
gline.ampl parameter value [1] 1.0e-3,1.0e-7,1


The parameter for this function is:

Parameter Definition
val If True , the user will be prompted to enter each parameter value, including support for changing the minimum and maximum values, when a model component is created. The default is False .


Setting this to True only makes sense in an interactive environment. It is designed to be similar to the parameter prompting provided by XSPEC.


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

See Also

freeze, guess, link, set_par, thaw, unlink