Re: Reconstructing data points from a InterpolatingFunction object
- To: mathgroup at smc.vnet.net
- Subject: [mg66504] Re: Reconstructing data points from a InterpolatingFunction object
- From: Peter Pein <petsie at dordos.net>
- Date: Wed, 17 May 2006 03:29:51 -0400 (EDT)
- References: <e4bits$1a9$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Eckhard Schlemm schrieb: > Hello everyone, > > My question is probably rather simple to answer but I just don't know how to > do it. > > I am nummerically solving a differential equation using NDSolve and then I > want to apply a NonlinearFit on the resulting InterpolatingFunction > object....and therefore need to have access to the data points which NDSolve > created and from which the InterpolatingFunction is created....Is there any > fast and direct way to get these data points ? (There must be....) > > Thanks in advance > > Eckhard > > Hi Eckhard, sol=y/.First@ NDSolve[{y''[x]==-y[x]+y'[x]Cos[x]+Sin[3x],y[0]==0,y'[0]==0},y,{x,0,10Pi}]; xyData=Transpose[{sol[[3,1]],sol[[4,2,1+Most@sol[[4,1]]]]}]; and compare p1=ListPlot[xyData,PlotJoined->True]; to p2 = Plot[ sol[x], {x, 0, 10Pi}, PlotPoints -> Length[sol[[4, 1]]] - 1, PlotStyle -> Red]; DisplayTogether[p1,p2] Peter