Re: Solving Simultaneous Differential Equations
- To: mathgroup at smc.vnet.net
- Subject: [mg78944] Re: Solving Simultaneous Differential Equations
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 13 Jul 2007 06:07:02 -0400 (EDT)
- Organization: Uni Leipzig
- References: <f74rj2$80f$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
Hi,
since you where not so kind to provide an example
here are the Roesseler equations
deqn={(x^\[Prime])[t]==-y[t]-z[t],(y^\[Prime])[t]==x[t]+a
y[t],(z^\[Prime])[t]==b+(-c+x[t]) z[t]}
param = {a -> 1/5, b -> 1/5, c -> 57/10};
roess = NDSolve[
Join[deqn /. param, {x[0] == 5, y[0] == 5, z[0] == 1}], {x[t],
y[t], z[t]}, {t, 0, 40}];
and
Plot[x[t] /. roess[[1]], {t, 0, 40}]
will plot the x[t] solution, y[t] you get with
Plot[y[t] /. roess[[1]], {t, 0, 40}]
and so on.
Regards
Jens
Nikhil Shankar wrote:
> Hey guys,
>
> I'm working on a model of the heart, which can be simplified to eleven simultaneous differential equations... I am solving them all with NDSolve and explicit Runge Kutta numerical integration. I am happy with the results, but I don't know how to plot a single function, of the eleven that are solved simultaneously.
>
> I can plot all 11 of them on one graph by using
>
> Plot[Evaluate[eqs /. %], {t, 0, 10}]
>
> where eqs are all 11 functions, and the last output was the set of the 11 interpolating functions. Plotting all 11 pretty much has no value to me though.
>
> How do I store the interpolating function data for each function so I can plot each by itself?
>
> Also, how can I save step-by-step results using Reap/Sow?
>
> Thanks for your help guys.
>