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Increasing precision of eigen value calculations
Posted Jan 24, 2011, 5:59 a.m. EST Version 3.5a, Version 4.0a 0 Replies
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Although this problem is not specific to any version of Comsol but I am working with 2D Perpendicular waves application mode of Comsol 3.5a's RF-module to find waveguide modes of a metallic cylinder in THz regime. Theoretically, I know that the mode exists with effective index equal to, for example, 1.000002345. But this seems to be too precise for eigen value solver and as a result it sometimes compute neff to be (again an example) 0.9999345 or anything just above one, for example, 1.023.
Since this is quite a huge error in the specific scenario I am working in, I was wondering if there is a possibility to inform Comsol to decrease the tolerance in error between actual and computed values at the cost of increased iterations. Could you suggest some way to do this? I have already toiled with the idea of increasing/decreasing relative tolerance (as high as 1000 and as low as 1e-10) but no avail. I don't think meshing is a problem either as increasing and decreasing refinement doesn't have any impact. Until now I have worked with Pardiso solver but may be there is another solver better suited to calculations this sensitive?
Thanks
Hello Shakeeb Bin Hasan
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