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Re: Finding only final values in NDSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg91274] Re: Finding only final values in NDSolve
  • From: "Kevin J. McCann" <Kevin.McCann at umbc.edu>
  • Date: Wed, 13 Aug 2008 04:38:58 -0400 (EDT)
  • Organization: University System of Maryland
  • References: <g7lvmq$fdj$1@smc.vnet.net>

Zakseidov,


How about something like this:

First[{y[3], y'[3]} /.
   NDSolve[{y''[t] + y[t] == 0, y[0] == 1, y'[0] == -1}, y, {t, 0, 3}]]


Kevin

zakseidov2 at gmail.com wrote:
> Dear Mathematica gurus,
> 1. I use NDSolve for integration from some t0 to some tf, but I'm
> interested only in FINAL VALUES y(tf),y'(tf).
>  How to do it (I mean: avoiding InterpolatingFunction and saving all
> intermediate values)?
> 2. I use WorkingPrecision -> 32(or larger). Final values y(tf),y'(tf)
> are of lesser Precision than 32D so i can't use them directly for
> further integrations. I do some manupulations to take more artificial
> digits...
> But what's the best way for doing it automatically not manually?
> 3. In other words: I need only values of y(t), y'(t) in fixed t_i with
> fixed interval d.
> How to do it using NDSolve economically without InterpolatingFunction
> (which I guess takes a lot of time if MaxSteps -> 10^8(or larger))?
> Thanks a lot,
> zakseidov
> 


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