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MathGroup Archive 2007

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Re: ndsolve ndsv problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg80847] Re: ndsolve ndsv problem
  • From: Chris Chiasson <chris.chiasson at gmail.com>
  • Date: Tue, 4 Sep 2007 03:42:45 -0400 (EDT)
  • References: <f96j3d$q3m$1@smc.vnet.net>

On Aug 6, 2:37 am, "Chris Chiasson" <ch... at chiasson.name> wrote:
> Steps to reproduce:
> 1. Issue this command (given to you in InputFrom due to a copy/paste problem)
>
> NDSolve[0.0005635632304299039*psi[R] ==
>    (2*Derivative[1][psi][R])/R +
>     Derivative[2][psi][R] &&
>   Derivative[1][psi][1] == 7.017487714753473 &&
>   psi[Infinity] == 0, psi, R]
>
> 2. Notice the warning (input returns unevaluated):
>
> NDSolve::ndsv: Cannot find starting value for the variable psi^\[Prime]. >>
>
> 3. The documentation for this error says:
>
> Generated when NDSolve is unable to solve the initial conditions to
> find a starting value in an initial value problem.
> This message can be generated by a variety of errors in the
> specification of initial conditions.
>
> Expected result:
> Something more helpful
>
> Maybe I am being too hard on Mathematica here, but maybe not,
> considering what Rob Knapp said in 1999 about Mathematica 4:http://forums.wolfram.com/mathgroup/archive/2000/Jun/msg00070.html
>
> Also, it appears the documentation hasn't changed for this error:http://forums.wolfram.com/mathgroup/archive/2000/Jun/msg00068.html
>
> --http://chris.chiasson.name/

1999 -> 2000
...



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