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Re: NDSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg86146] Re: NDSolve
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Mon, 3 Mar 2008 04:41:38 -0500 (EST)
  • References: <fqet8u$jff$1@smc.vnet.net>

Hi,

a) we are not clairvoyants and it is rather hard to imagine what
    you wish to do without an example
b) if there is a "sudden changes in the slope" the step size control
    will reduce the step size dramatical and monitoring the step size
    is a good indicator for a "sudden changes in the slope"
c) the case that "mean that Mathematica took the wrong root of a complex 
number" mean in many cases the the right hand side of your ODE's
   are not Lipshitz continuous and that there exist no solution
   at all

Regards
   Jens

Alex Cloninger wrote:
> So I'm running an NDSolve operation on a series of coupled ODE's.  I want to look at specific results every 10 steps or so to see if I have any sudden changes in the slope of the graph (the sudden changes would mean that Mathematica took the wrong root of a complex number).  I'm not sure what I can do to get this information.
> 
> If anyone could help me out, I'd be very appreciative.
> 
> Thanks,
> Alex
> 


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