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Last modified: December 2010

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AHELP for CIAO 4.3 Sherpa v1


Context: modeling


Toggle parameter prompting for initial model values


paramprompt( [val=False] )


The paramprompt command controls whether Sherpa prompts the user for initial parameter values when a model component is created.

  • val - a boolean value which indicates whether parameter prompting is off (the default, val=False) or on (val=True).

If parameter prompting is turned on, the user is queried for the initial value of each model component parameter when it is established. At the model component prompt, either specify the initial value for the component or just hit <Return> to accept the default value.

In addition to the initial value, the minimum and maximum parameter limits may be set at the prompt. They must be comma-separated and specified in the order "value, min, max".

Example 1

sherpa> paramprompt(True)
sherpa> set_model(gauss1d.g1)

Parameter prompting is turned on, then a gauss1d model is created and named "g1". The screen output is:

g1.fwhm parameter value [10] 20
g1.pos parameter value [0] 0.05
g1.ampl parameter value [1]

Initial parameter values are set for the fwhm and pos parameters, while the default of the ampl parameter is accepted by hitting <Return>.

Example 2

sherpa> paramprompt(True)
sherpa> set_model(gauss2d.src)

Parameter prompting is turned on, then a gauss2d model is created and named "src". The screen output is:

src.fwhm parameter value [20] 20, 0.1, 300
src.xpos parameter value [0] 4024
src.ypos parameter value [0] 4250
src.ellip parameter value [0]
src.theta parameter value [0]
src.ampl parameter value [1] 20, 0.1, 1000

The initial value, minimum, and maximum are set for the fwhm and ampl parameters. An initial value only is set for the xpos and ypos parameters; the ellip and theta values are left unchanged by hitting <Return>.

See Also

freeze, guess, link, set_par, thaw, unlink

Last modified: December 2010
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