MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: numerical solution of an ODE doesn't make sense


"Ita" <kitamar at actcom.net.il> writes:

> Hello, and thanks in advance to any response.
> I solved a 2nd degree ode with NDSolve for the unknown x(t) for 2 time
> domains: 0<t<100 and 0<t<700, with the same boundary conditions.
> than I ploted the two solutions for 0<t<20, and they came out different ! it
> is like the solution in t<20 is influenced by the solution in t>100 - it
> doesn't make sense.
> thanks,
> Itamar.

Hello,
this certainly depends on the differential equation and the boundary
conditions! 
Consider the simple problem
u'' = -1
u(0) = 0
u'(L) =0
(this might model the longitudinal deformation of an elastic rod under
constant axial load).
The solution strongly depends on L.
Alois
 


  • Prev by Date: Re: Combining vectors to form a matrix
  • Next by Date: Re: 3D Pascal's Triangle (Cone?)
  • Previous by thread: Re: numerical solution of an ODE doesn't make sense
  • Next by thread: Simple Module Code