| Author | Message | |||
     Matthew Lloyd Davies (mdavies) Member Username: mdavies Post Number: 4 Registered: 10-2004 |
Could someone please help to fix this code. I am trying to solve a 3 variable nonlinear ODE problem but I keep getting the message: Duplicate co-ordinate name Code attached. Regards M
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| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 249 Registered: 06-2003 |
The default coordinate system is two-dimensional Cartesian with coordinates X and Y. In that system, you cannot redefine X or Y as a variable. You must either use a different name for your variable, or change the coordinate names using the COORDINATES command. | |||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 250 Registered: 06-2003 |
The diagnostic issued for this error is not very helpful. I will try to make it more informative in the next version release. | |||
| Matthew Lloyd Davies (mdavies) Member Username: mdavies Post Number: 5 Registered: 10-2004 |
Thanks Robert  | |||
| Mohammad Rahmani (mrahmani) Junior Member Username: mrahmani Post Number: 3 Registered: 10-2004 |
The derivation seems to be wrong. The precursor concentration should be decreasing. It needs a minus sign in the first equation. Also the set of ODEs are stiff and you need a stiff solver like "ode15s" in Matlab. I am not sure about FlexPDE solver, but if it uses a general solver then you can not obtain the right answer. | |||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 252 Registered: 06-2003 |
FlexPDE uses a stiff solver. See my response to Rahmani's separate posting. |
Double salnikov