Re: serious NDSolve bug?
- To: mathgroup at smc.vnet.net
- Subject: [mg44026] Re: serious NDSolve bug?
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Sat, 18 Oct 2003 03:12:17 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <bmod0f$hof$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
and whe you write
f[kampas_?NumericQ]:=(u[\[Xi]] /. First[sprendinys1 =
NDSolve[{Derivative[2][\[Psi]][\[Xi]] == (\[Xi]^2 - energija)*
\[Psi][\[Xi]], Derivative[1][u][\[Xi]] == \[Psi][\[Xi]]^2,
\[Psi][\[Xi]min] == 0,
Derivative[1][\[Psi]][\[Xi]min] == kampas, u[\[Xi]min] == 0},
{\[Psi][\[Xi]], u[\[Xi]]},
{\[Xi], \[Xi]min, \[Xi]max}]] /. \[Xi] -> \[Xi]max)
and call
teisingasKampas =
FindRoot[f[kampas]==1, {kampas, -0.04, 0.04}]
all works as expected *and* your code is better readable.
BTW: Can you avoid postings with Mathematica's special characters ?
Regards
Jens
Artþras Acus wrote:
>
> Hi, All
>
> In version 4.1 the following code works as expected.
>
> \[Xi]min = -5; energija = 2*n + 1 /. n -> 1; \[Xi]max = 5;
>
> teisingasKampas =
> FindRoot[
> (u[\[Xi]] /. First[sprendinys1 =
> NDSolve[{Derivative[2][\[Psi]][\[Xi]] == (\[Xi]^2 - energija)*
> \[Psi][\[Xi]], Derivative[1][u][\[Xi]] == \[Psi][\[Xi]]^2,
> \[Psi][\[Xi]min] == 0,
> Derivative[1][\[Psi]][\[Xi]min] == kampas, u[\[Xi]min] == 0},
> {\[Psi][\[Xi]], u[\[Xi]]},
> {\[Xi], \[Xi]min, \[Xi]max}]] /. \[Xi] -> \[Xi]max) == 1,
> {kampas, -0.04, 0.04}]
>
> In 5.0 I get message, that kampas is not a number. Changing FindRoot[ ]
> by RootSearch[] (from Ted Ersek package) did not help, therefore I
> suspect that there is serious bug in NDSolve argument evaluation
> procedure. How I can make it to work ?
>
> Sincerely, Arturas Acus