MathGroup Archive 1997

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Help getting values from NDSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg6826] Re: [mg6783] Help getting values from NDSolve
  • From: penny at suu.edu (Des Penny)
  • Date: Mon, 21 Apr 1997 02:03:24 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

>I'm relatively new to Mathematica and need some help with the NDSolve
>function.  I have used it to solve an ordinary differential equation and got
>the expected interpolating function which I then plotted.  The plot is great
>but I would like a list of coordinates so that I can analyze them further
>and possibly import into a "prettier" graphing package.
>
>Any help would be appreciated.
>
>Please email and post (mosser at earthlink.net)


Hi Chris:

I decided to do some more work on this question.  I was interested in
pulling the data directly from the InterpolatingFunction.

Here is my code.  I've given it in expanded form so that the components
would be easy to understand:



sol=NDSolve[{y'[x]==y[x],y[0]==1},y,{x,0,2}];

fun= y /. sol;
args=fun /. InterpolatingFunction->List;

xvalues=args[[1,3,1]];
yvalues=Map[First,args[[1,4]]];

data=Transpose[{xvalues,yvalues}];
ListPlot[data]

Hope this helps.

Cheers,

Des Penny


-------------------------------
Des Penny
Physical Science Dept.
Southern Utah University
Cedar City, UT 84720

VOICE: (Office): (801) 586-7708
       (Home)  : (801) 586-2286
FAX:    (801) 865-8051
e-mail: penny at suu.edu
-------------------------------




  • Prev by Date: Re: Help getting values from NDSolve
  • Next by Date: Integrate[1/2+1/2 Erf[z],{z,-inf,0}]
  • Previous by thread: Re: Help getting values from NDSolve
  • Next by thread: Re: Help getting values from NDSolve