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Problem with Large domain

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Hi

I am simulating propagation through a simple waveguide in 3D.
The simulation is working perfectly as long as the length of the waveguide is below 10um. When I increase the device length to 10um, the simulation continues and reaches the convergence, however at the final step an error message appears. as below.

Failed to find a solution.
Very ill-conditioned preconditioner.
The relative residual is more than 1000 times larger than the relative tolerance.
Returned solution is not converged.

I have attached the file. I would appreciate any suggestions.

Thank you

Kapil


2 Replies Last Post 12 feb 2015, 09:40 GMT-5
COMSOL Moderator

Hello Kapil Debnath

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Mohammed Thameemul Ansari

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Posted: 10 years ago 8 feb 2015, 21:40 GMT-5
Hello sir

The same error am facing now. Did you fix the problem?

May i know what is the solution for the problem?

The relative residual is more than 1000 times larger than the relative tolerance.
Returned solution is not converged.
Hello sir The same error am facing now. Did you fix the problem? May i know what is the solution for the problem? The relative residual is more than 1000 times larger than the relative tolerance. Returned solution is not converged.

Walter Frei COMSOL Employee

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Posted: 10 years ago 12 feb 2015, 09:40 GMT-5
Dear Kapil,

You may want to check the geometric scales here. You would want units of microns, not meters.
Dear Kapil, You may want to check the geometric scales here. You would want units of microns, not meters.

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