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"
<mosser at earthlink.net> wrote:
> 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
Please don't send any junk mail or advertisements. For personal mail please send to: Christian.Jost at epc.u-psud.fr