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Problems with parametric sweep

Posted Jun 24, 2013, 4:46 p.m. EDT Low-Frequency Electromagnetics, Fluid & Heat, Structural Mechanics Version 4.3b 3 Replies

Anders Karlsson
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I have a model that I want to investigate with differens values on at least one of the design variables. If I change the variables value manually and compute, there is no problem but if i use variable sweep i get the following error message:

Failed to find a solution.
Maximum number of Newton iterations reached.
Returned solution is not converged.
-Feature: stationary solver1(sol2/s1)
-Error: Failed to find a solution

In parametric sweep I use for example the following parameter value:
range(0.03,0.01,0.06)
so it should only be four values that i'm trying to calculate now (when testing)

When I have been searching the internet all I can find is that it might be something about tolerance but first of all I don't understand where to set the tolerance and second of all, why does it work when i change the values manually?
3 Replies Last Post Jun 28, 2013, 4:09 p.m. EDT
farhad farzbod
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Posted: 1 decade ago Jun 27, 2013, 6:48 p.m. EDT
I have the same problem, I was wondering if Comsol tries to save everything in the memory and then can't handle it. Because it goes up to certain number in the sweeps (update the sweep and u can see that the solution existed for couple of them). I am working on it and try other ways to get around it or see what was wrong
I have the same problem, I was wondering if Comsol tries to save everything in the memory and then can't handle it. Because it goes up to certain number in the sweeps (update the sweep and u can see that the solution existed for couple of them). I am working on it and try other ways to get around it or see what was wrong
Josh Thomas Certified Consultant
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Posted: 1 decade ago Jun 28, 2013, 8:28 a.m. EDT
Anders-

Are you using the "Parametric Sweep" function or the "Continuation" method of sweeping?

The "Continuation" method uses the solution of the previous parameter as the initial guess at the solution of the next parameter and so on. Perhaps this is why the solver does not converge (ie because you are using a different initial guess than if you simply solve for the single parameter). Although, usually using a continuation parameter helps (not hurts) the possibility of convergence.

The "Parametric Sweep" method is usually reserved for situations where you are sweeping some parameter that affects the geometry or mesh. In this case, the previous parameter solution is not used as the initial guess for the next parameter solution process.

Best regards,
Josh Thomas
AltaSim Technologies
Anders- Are you using the "Parametric Sweep" function or the "Continuation" method of sweeping? The "Continuation" method uses the solution of the previous parameter as the initial guess at the solution of the next parameter and so on. Perhaps this is why the solver does not converge (ie because you are using a different initial guess than if you simply solve for the single parameter). Although, usually using a continuation parameter helps (not hurts) the possibility of convergence. The "Parametric Sweep" method is usually reserved for situations where you are sweeping some parameter that affects the geometry or mesh. In this case, the previous parameter solution is not used as the initial guess for the next parameter solution process. Best regards, Josh Thomas AltaSim Technologies
farhad farzbod
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Posted: 1 decade ago Jun 28, 2013, 4:09 p.m. EDT
I used "Parametric Sweep" under the "Study". I this point I am not sure about the source of error
I used "Parametric Sweep" under the "Study". I this point I am not sure about the source of error

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