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MathGroup Archive 2007

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ndsolve ndsv problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg79829] ndsolve ndsv problem
  • From: "Chris Chiasson" <chris at chiasson.name>
  • Date: Mon, 6 Aug 2007 03:35:03 -0400 (EDT)

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/


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