Re: NDSolve does not work in shooting method

*To*: mathgroup at smc.vnet.net*Subject*: [mg44143] Re: NDSolve does not work in shooting method*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Fri, 24 Oct 2003 04:24:12 -0400 (EDT)*Organization*: Universitaet Leipzig*References*: <bn8du7$nfi$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de*Sender*: owner-wri-mathgroup at wolfram.com

Hi, system[a_?NumericQ] := {y1'[x] == y2[x], y2'[x] == -Sin[y2[x]] + Cos[5x], y1[-1] == 0, y2[-1] == a}; myODEsoln[a_?NumericQ] := NDSolve[system[a], {y1[x], y2[x]}, {x, -1, 1}] yend[a_?NumericQ] := (y1[x] /. myODEsoln[a]) /. x -> 1 bc = FindRoot[First[yend[a]] == 0, {a, -2, 2}]; Plot[Evaluate[y1[x] /. myODEsoln[a /. bc]], {x, -1, 1}, AxesLabel -> {"x", "y1(x)"}]; Regards Jens Alexander Koulidis wrote: > > This comes from a newbie in Mathematica, so have some mercy.... > > I'm trying to reproduce some examples of the shooting method that have been > published in this forum, but Mathematica 5.0 shows some strange behavior > with NDSolve. > > In http://forums.wolfram.com/mathgroup/archive/2001/Aug/msg00128.html Brian > wrote: > > The following code implements the shooting technique > > system[a_] := {y1'[x] == y2[x], y2'[x] == -Sin[y2[x]] + Cos[5x], > y1[-1] == 0, > y2[-1] == a}; > myODEsoln[a_] := NDSolve[system[a], {y1[x], y2[x]}, {x, -1, 1}] > yend[a_] := (y1[x] /. myODEsoln[a]) /. x -> 1 > bc = FindRoot[First[yend[a]] == 0, {a, -2, 2}]; > Plot[Evaluate[y1[x] /. myODEsoln[a /. bc]], {x, -1, 1}, > AxesLabel -> {"x", "y1(x)"}]; > > While the code was working fine in v. 4.2, now it produces warnings of > "NDSolve::ndinnt :" or "RuleDelayed::rhs". > Can someone test this code in v5.0? Does anyone have some idea of what is > happening and should I implement a typical shooting method? > Thanks in advance. > Alexander Koulidis, Athens, Greece