Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Problems with parametric sweep

Please login with a confirmed email address before reporting spam

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 28 giu 2013, 16:09 GMT-4

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 27 giu 2013, 18:48 GMT-4
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

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 28 giu 2013, 08:28 GMT-4
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

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 28 giu 2013, 16:09 GMT-4
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

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.