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Hi

In other words, from your graph, you are saying you have some harmonic bahaviour (of unknown frequency)with a varying amplitude that after some time reaches a saturation, so you want to detect when the amplitude has reached it's "steady state.

Clearly if you know the periode, you can take a running integration of one periode and plot that, then you get rid of the main oscillations. As a priori you do not know the frequency, then perhaps if you use the calculated time signal and run an autocorrelation after each time step and put a stop condition on the derivative of the result ?, just a crazy idea.

make a test with an function such as a*(1-exp(-k/t))*sin(2*pi*f*t)

Have fun Comsoling
Ivar

Complement:

I tried it out in Maple, not good enough as the result is oscillating, should have though about that, but there should be a trivial way to extract the average amplitude from such a signal.
The file below might give you some ideas, I would have to go back to my signal processing books, that subject has slipped away I notice ;)

The main issue is to get a function that is not to sensitive to noise and offset

Ivar

Wow, that looks more trickier than I thought. Many thanks Ivar.

Hi

yes I agree, that is why I believe there must be a simpler way ;)

What I show is the lazy engineer trying out some formulas, my reference books are in my office and it's the week-end, nice weather and I'm at home, to far to fetch those. But you might find a working trick, no ?

have fun Comsoling
Ivar

"How can one ... tell the solver to stop?"

Excellent question for our resident Comsol gurus.

It would be great to be able to embed a stop condition in Comsol that would abort the computation if some particular condition were met, say in a time dependent calculation. Let's say you set up a problem to run for 10 sec but you find the computation is going awry after 1 sec. Rather than wait around for the full 10 sec (which could be 10 min or 10 hr in computation time), it would be better to just abort the whole thing. This would require being able to set up some function for performing a test at each time step, and then issuing a command to stop the computation (probably also instructing Comsol to do clean up work) if necessary.

Is this possible?

Hi

yes there is a "stop condition" in the (or just for some?) solver section (advanced ones ?), that does as if you manually hit the "stop button" in the log, up to you to define your criteria, try a indexed search on the pdf doc more info, notls such info is somewhat spread out often in examples in the different docs.

Have fun Comsoling
Ivar

Hi

yes there is a "stop condition" in the (or just for some?) solver section (advanced ones ?), that does as if you manually hit the "stop button" in the log, up to you to define your criteria, try a indexed search on the pdf doc more info, notls such info is somewhat spread out often in examples in the different docs.

Have fun Comsoling
Ivar

Indeed. e.g. for the case of inverted meshes, you can tell comsol to stop and do remeshing.

Meanwhile, back to the problem itself:
Is there a way to apply some functions on the results? (FFT, mean,...)?

Sorry, I meant to stop a computation programmatically, not manually. Further, it would be useful to be able to write out some diagnostics at the same time, to be able to see the state of the computation at the time it stopped. It would be rather like a try-catch approach in Matlab or C/C++ programming. Would this be possible to do by first saving a model in Matlab, manually inserting the necessary diagnostics in the Matlab code, then running it from there? I'll check the docs as you suggested. Thanks.