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MathGroup Archive 2005

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ndsolve error message

  • To: mathgroup at smc.vnet.net
  • Subject: [mg56648] ndsolve error message
  • From: Chris Chiasson <chris.chiasson at gmail.com>
  • Date: Sun, 1 May 2005 03:13:30 -0400 (EDT)
  • Reply-to: Chris Chiasson <chris.chiasson at gmail.com>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi MathGroup gurus,

I get the following error from my input to NDSolve, but I am not sure
if I am actually violating the rule it says I am:

Boundary values may only be specified for one independent variable.
Initial values may only be specified at one value of the other
independent variable.

***Do you think I have violated the rule? What should I change?***

the input was as follows: (copy it into Mathematica and hit
ctrl+shift+n to get a more readable form)

NDSolve[\[ScriptCapitalN]A[z, t] == (\[ScriptCapitalN]A[z, t] +
\[ScriptCapitalN]B[z, t] + \[ScriptCapitalN]C[z, t])*÷A[z, t] -
    (0.0003610152163600286*Derivative[1, 0][÷A][z, t])/
     ((0.3040465336986682*÷C[z, t])/(÷A[z, t] + ÷B[z, t]) + 
      (0.39170805107300855*÷B[z, t])/(÷A[z, t] + ÷C[z, t])) && 
  \[ScriptCapitalN]B[z, t] == (\[ScriptCapitalN]A[z, t] +
\[ScriptCapitalN]B[z, t] + \[ScriptCapitalN]C[z, t])*÷A[z, t] -
    (0.0003610152163600286*Derivative[1, 0][÷B][z, t])/
     ((0.2905456429313062*÷C[z, t])/(÷A[z, t] + ÷B[z, t]) + 
      (0.39170805107300855*÷A[z, t])/(÷B[z, t] + ÷C[z, t])) && 
  \[ScriptCapitalN]C[z, t] == (\[ScriptCapitalN]A[z, t] +
\[ScriptCapitalN]B[z, t] + \[ScriptCapitalN]C[z, t])*÷A[z, t] -
    (0.0003610152163600286*Derivative[1, 0][÷C][z, t])/
     ((0.2905456429313062*÷B[z, t])/(÷A[z, t] + ÷C[z, t]) + 
      (0.3040465336986682*÷A[z, t])/(÷B[z, t] + ÷C[z, t])) && 
  0.0003610152163600286*(÷A[z, t]*Derivative[0, 1][P][z, t] + 
     P[z, t]*Derivative[0, 1][÷A][z, t] + 
     2769.9663468*Derivative[1, 0][\[ScriptCapitalN]A][z, t]) == 0 && 
  0.0003610152163600286*(÷B[z, t]*Derivative[0, 1][P][z, t] + 
     P[z, t]*Derivative[0, 1][÷B][z, t] + 
     2769.9663468*Derivative[1, 0][\[ScriptCapitalN]B][z, t]) == 0 && 
  0.0003610152163600286*(÷C[z, t]*Derivative[0, 1][P][z, t] + 
     P[z, t]*Derivative[0, 1][÷C][z, t] + 
     2769.9663468*Derivative[1, 0][\[ScriptCapitalN]C][z, t]) == 0 && 
  ÷A[z, t] + ÷B[z, t] + ÷C[z, t] == 1 && 
  ÷A[z, 0] == ÷A[0, t] == 0.13238383827902114 && 
  ÷B[z, 0] == ÷B[0, t] == 0.6681373176389893 && 
  ÷C[z, 0] == ÷C[0, t] == 0.1994788440819895 && 
  P[z, 0] == P[0, t] == 100000 && \[ScriptCapitalN]A[1/4000, t] == 
   0.011156006364769414 && \[ScriptCapitalN]B[1/4000, t] == 0 &&
\[ScriptCapitalN]C[1/4000, t] == 0,
  {P, \[ScriptCapitalN]A, \[ScriptCapitalN]B, \[ScriptCapitalN]C, ÷A,
÷B, ÷C}, {z, 0, 1/4000}, {t, 0, 2}]

Thank you for your valuable time,
-- 
Chris Chiasson
http://chrischiasson.com
Kettering University
Mechanical Engineering
Graduate Student
1 810 265 3161


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