Re: Reconstructing data points from a InterpolatingFunction object

*To*: mathgroup at smc.vnet.net*Subject*: [mg66515] Re: Reconstructing data points from a InterpolatingFunction object*From*: Paul Abbott <paul at physics.uwa.edu.au>*Date*: Wed, 17 May 2006 03:30:38 -0400 (EDT)*Organization*: The University of Western Australia*References*: <e4bits$1a9$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <e4bits$1a9$1 at smc.vnet.net>, "Eckhard Schlemm" <e.schlemm at hotmail.de> wrote: > I am nummerically solving a differential equation using NDSolve and then I > want to apply a NonlinearFit on the resulting InterpolatingFunction > object.... What do you want the NonlinearFit to do? Note that in Version 5 you can use FindFit instead of NonlinearFit. Also, you can use InterpolatingFunctions directly, rather than sampling or re-sampling them. I think a concrete example is likely to generate a more useful answer. > and therefore need to have access to the data points which NDSolve > created and from which the InterpolatingFunction is created.... I don't follow the use of therefore here. The data points at which NDSolve samples the solution depends on the automatic and optional settings supplied to NDSolve -- so I don't see why accessing these points is required. You can, of course, just generate a Table of points by re-sampling the InterpolatingFunction. > Is there any fast and direct way to get these data points ? > (There must be....) See the Advanced Documentation for NDSolve. This can be opened directly be executing the following command: NotebookOpen[FrontEnd`FileName[ {$TopDirectory, "Documentation", "English","RefGuide", "AdvancedDocumentation","DifferentialEquations"}, "Packages.nb"]] Cheers, Paul _______________________________________________________________________ Paul Abbott Phone: 61 8 6488 2734 School of Physics, M013 Fax: +61 8 6488 1014 The University of Western Australia (CRICOS Provider No 00126G) AUSTRALIA http://physics.uwa.edu.au/~paul