## Institut für Astronomie und Astrophysik## Abteilung AstronomieSand 1, D-72076 Tübingen, Germany |

fit

- Name
- Purpose
- Category
- SYNTAX:
- Input Parameters
- OPTIONS:
- SETUP:
- Description
- Side Effects
- REMARK:
- Example
- Revision History

fit

perform fit process of given model to data

cafe

fit, [iterations][,/selected][,/quiet]

iterations - (optional) Number of iterations to perform before query to prolong.

quiet - Do not show fit processing. selected - Apply fit to selected data points only. nodata - Take also models into account which are in groups containing no data. May be usefull when building complex models refering one to other. iterstop - Stop when key 'q' pressed. Default true.

All inputs/options may be set with the "set" command. The command prefix is "fit".

The fit command performs the actual data fitting for given models. All groups containing (defined) data and a model are taken into account. The result are the best fit parameters with errors estimated from the inverted covariance matrix (the hessian). Fit results may be shown with "> show,result". The data/model distance is plotted with the plot model "res". During fitting parameter handling is as follows: - if a parameter is frozen (fixed flag = 1) the parameter will not be touched while fitting. - if a parameter is tied to another parameter this parameter will copy the latter parameter value (in case of expressions the value will be mapped with this expression). - groups which contain a model but no valid data points are ignored. In case of the selected flag (s.a.) only selected data points are taken into account, i.e. if no data points are selected the group is ignored. - groups which contain valid data points but no model are ignored.

Changes parameter values/errors in environment according fit result.

Long lasting fit processes may be interrupted with "q".

> model, "sin+lin", 2 > fit -> fit result > plot,data+model,res

$Id: cafe_fit.pro,v 1.25 2004/03/06 14:29:08 goehler Exp $

Last modified by pro2html on 2005 January 04 at 16:04 UTC

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]

Jörn Wilms (wilms@astro.uni-tuebingen.de)

Updated automatically