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Does NDSolve have an upper limit requirement of the number of equations?

Lammond Wan
Posted 8 years ago
POSTED BY: Lammond Wan
9 Replies
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POSTED BY: Michael Rogers
POSTED BY: Michael Rogers
Lammond Wan
Lammond Wan
Posted 8 years ago

Sorry to express it that way, my English is so poor that I can't describe what I mean to say correctly. No doubt I should fix my problem myself, and I'm really appreciate your help. Thank you very much!
POSTED BY: Lammond Wan

Try add option to NDSolve: 

 Method->{"EquationSimplification"->"Residual"}

Did it help?
POSTED BY: Mariusz Iwaniuk
Lammond Wan
Lammond Wan
Posted 8 years ago

Wow, the error disappears! I will check the correctness of the answers later, but I need to thank you at first. Moreover, how does it works by setting the method of equation simplification?
POSTED BY: Lammond Wan

You can find the answer how it works probably here -> Differential-Algebraic Equations -> Introduction

Regards,MI
POSTED BY: Mariusz Iwaniuk
Lammond Wan
Lammond Wan
Posted 8 years ago
POSTED BY: Lammond Wan

NDSolve tries to solve for the highest derivatives (or the derivatives of the equivalent first-order system). If solving fails, then you get the error. Try solving the system yourself. There may also be a time constraint on solving, but I'm not sure.
POSTED BY: Michael Rogers
Lammond Wan
Lammond Wan
Posted 8 years ago

As you can see in my code, the founded equations are all of first order, but its amount may reach to 200 000 if needed. The error occurs when the amount of ODEs gets greater than only 10 000. It really disappoints me. By the way, what do you mean by mentioning solving it myself? Is there other effective way to solve ODE set? I'm a beginner of MMA, sorry to ask you this question. Thanks!
POSTED BY: Lammond Wan
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