Institut für Astronomie und Astrophysik
Abteilung AstronomieSand 1, D-72076 Tübingen, Germany
define model of fit
modelstring - Defines the models to apply. The string may consist of several models to apply which could be combined via algebraic operators as there are: "+" - adds two models "-" - subtracts two models "*" - multiplies two models "/" - divides two models Parentheses are allowed to group the operations. Chaining of models is possible by enclosing the inner model within parentheses: sin(lin) -> y = sin(lin(x)). Model components must be lower case. If a component is upper case or starts with a number it is interpreted as a usual IDL function/expression. This can be used to exploit simple/built in functions.
> model, const*SIN(x*2*!DPI) -> use two model components (const and x) and a fix function (SIN) with a built in constant (!DPI). Models can be expanded by using a model string which starts with one of the algebraic operators above: "+","-","*","/". In this case the former model and its parameters will be kept. Models can be copied by assignment using the "= <group>" Operator. In this case all parameters are copied also.
> model, = 2 -> Copy model and its parameters from group 2. group - (optional) The data group for which the model should be applied. Default is the current group which can be changed with "chgrp". Must be in range [0..29].
/quiet - Do not ask for parameter values (useful for command file processing). Also do not report fit statistic.
All options may be set with the "set" command. The command prefix is "model".
The models are defined in separate modules which could be added and maintained separately. Available models could be list with help,model,all while a specific model can be shown with help,model, <model> Models can be add by defining a function in a separate file. Refer maintenance.
The option /add to add a model to an existing one is still supported but deprecated.
Stores model information in environment for given group
> model, "sin+lin", 2
$Id: cafe_model.pro,v 1.20 2004/08/18 07:26:43 goehler Exp $
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