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Re: Coupled second-order nonlinear ODEs

  • To: mathgroup at smc.vnet.net
  • Subject: [mg90527] Re: Coupled second-order nonlinear ODEs
  • From: Alois Steindl <Alois.Steindl at tuwien.ac.at>
  • Date: Fri, 11 Jul 2008 05:57:11 -0400 (EDT)
  • References: <g54olq$f15$1@smc.vnet.net> <g56taq$3s5$1@smc.vnet.net>

Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com> writes:

>
> Your system is really stiff, I mean *really* stiff, on the given range 
> for y. Do you need m as large as twenty? Everything is fine up to m 
> about 1.4. Setting m = 7/5, we do not need to add any options to NDSolve 
> and it does not return any warning message.
>
Hello,
my impression is, that the system isn't just stiff, but that there is
a "finite time blow up" close to y=1.4, where the solution has a pole.
Compare the simple nonlinear ode 
y'=y^3, y(0)=1.

Alois
 


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