Re: Help getting values from NDSolve

• To: mathgroup at smc.vnet.net
• Subject: [mg6849] Re: Help getting values from NDSolve
• From: jost at no-junk-mail.fr (Christian Jost)
• Date: Thu, 24 Apr 1997 02:44:30 -0400 (EDT)
• Organization: Universite Paris-Sud XI
• Sender: owner-wri-mathgroup at wolfram.com

```In article <5j75mr\$5ok at smc.vnet.net>, "Christopher Moss"

> 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.
>
After simulation
In[6]:=
solution = NDSolve[{x'[t]== 1.7 x[t],x[0]==1.0},x,{t,0,10}];

solution is now like a list of rules, use Apply or its shortcut /. to
extract values
In[7]:=
{5,x[5]} /. solution

Out[7]=
{{5,4914.83}}

In[9]:=
Table[{t,x[t]} /. solution,{t,0,10}]

Out[9]=
\!\({{{0, 1.`}}, {{1, 5.47398247034581775`}}, {{2, 29.9643350630800888`}}, {{
3, 164.023441789861523`}}, {{4, 897.857167517260457`}}, {{5,
4914.8291275592113`}}, {{6, 26903.5623625458697`}}, {{7,
147268.905784071213`}}, {{8, 806143.319096327637`}}, {{9,
4.41279377748526435`*^6}}, {{10, 2.41554318832612802`*^7}}}\)

hth, Christian.

ps: there are good examples in the mathematica book, you will find
solutions to all kind of syntax problems faster than on usenet ;-)

--
*********************************************************************
Christian Jost, Université Paris-Sud XI, Orsay, France