How i choose the best solver ?

How i choose the best solver for my simulink model and why i get different results if i use a different solver?

[Walter Roberson]

Sunspots.

Computer memory makes very nice solar cosmic ray detectors, so the larger the code, the more chance it has to be altered in memory by solar cosmic rays. This leads to different sized solvers tending to give different answers.

[dimitris]

I didn't know that cosmic rays interact with computer memory, it is very interesting.

[Walter Roberson]

It's true!

http://en.wikipedia.org/wiki/Dynamic_random-access_memory#Error_detection_and_correction

"The majority of one-off ("soft") errors in DRAM chips occur as a result of background radiation, chiefly neutrons from cosmic ray secondaries, which may change the contents of one or more memory cells or interfere with the circuitry used to read/write them."

and see also this New Scientist article: http://www.newscientist.com/blog/technology/2008/03/do-we-need-cosmic-ray-alerts-for.html

Answer 1

[Fangjun Jiang]

See the link. choosing a solver

[Walter Roberson]

That link just explains what all the solvers are and shows that they use different formula. That link doesn't explain why the different formula may give different results, or why the ones that give different results are not considered buggy. How should one know which solver to use to get the "right" answer?

Now, heliostigmata: that maybe be all the explanation you really need!

[Fangjun Jiang]

That link is the complete handbook for choosing a solver. It provides the explanation about all the solvers provided, how to deal with different problems, how to deal with discrete or continuous system, how to choose the tolerance, how to improve the simulation accuracy, etc.

Why do you get different results if using different solvers? That is a good question. I bet you can't draw the same line if using a pencil than using a paintbrush. The results are different because at least one of the tools is wrong. You should not care why the results are different. There is no point to compare the pencil with the paintbrush. You should care which solver could give you the most accurate result. For that, you need to follow the link, understand the solvers and understand the nature of your problem and then choose the best one.