- Create the function to be integrated correctly, e.g. avoid numerical problems.
- ODE45 and the other intergrators of Matlab require smooth functions. Therefore avoid commands like: IF, RAND, DATE, TIME, ABS, etc.
- Adjust the relative and absolute tolerance appropriately. It is hard science to define this term accurately.
- Control the senistivity of the result to variations of the input: Start the integration at y and y+eps(y) and compare the effects. If small variations produce large differences, the system is instable and an accurate integration is not possible with the current choice of tolerances.
Using a large integration range and ode45
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Hi all,
I have a set of equations that needs to be solved over a very large domain (say x > 1000, where x is the integration range).
What is the best way to do this to ensure accurate results using ode45?
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Answers (1)
Jan
on 6 Dec 2012
This is a very general question. Therefore only a general answer is possible.
It is unclear, why "1000" should be very large. If you simulate vehicel dynamics of a car on different terrain and the measurement units are seconds, this is a small period. If you simulate the molecular dynamics in the engine of the same car, 1000 seconds would be hilariously gigantic.
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