MathGroup Archive 2005

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

Search the Archive

Re: Boundary conditions in NDSolve

  • To: mathgroup at
  • Subject: [mg56811] Re: [mg56773] Boundary conditions in NDSolve
  • From: Chris Chiasson <chris.chiasson at>
  • Date: Fri, 6 May 2005 03:01:09 -0400 (EDT)
  • References: <>
  • Reply-to: Chris Chiasson <chris.chiasson at>
  • Sender: owner-wri-mathgroup at

Take a guess at the derivative on the left edge. Comput the function
value at the right edge. Guess a new value and recompute... After your
search is reasonably wide, you could hone down on the lhs derivatives
that give the rhs boundary condition.

I am having a similar problem, but with PDEs and more variables...

On 5/5/05, YZ <z at ***> wrote:
> Hello,
> when I NDSolve a 2nd order DE, I cant seem to give two boundary
> conditions at different point of an interval I am solving it on:
> NDSolve[{f''[x]==K^2*Sin[f[x]],f'[-L]==A, f[-L]==B},f,{x,-L,L}]
> produces good result, but i.e.
> NDSolve[{f''[x]==K^2*Sin[f[x]],f'[-L]==A, f[L]==B},f,{x,-L,L}]
>   ____here derivative is given at left edge, but the functi0n itself is
> given at the right edge___
> produces error:
> NDSolve::"bvlin"
> "The differential equation(s) and/or boundary conditions are not linear
> in the dependent variables. NDSolve requires linearity to compute the
> solution of a multipoint boundary value problem. "
> Is there a way around this?
> Thanks
> YZ

Chris Chiasson
1 (810) 265-3161

  • Prev by Date: Re: Controlled evaluation of functions
  • Next by Date: Re: Bug in Integrate in Version 5.1?
  • Previous by thread: Boundary conditions in NDSolve
  • Next by thread: Re: Boundary conditions in NDSolve