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