[vtkusers] ICP Error: vtkMath::Jacobi: Error extracting eigenfunctions

[Maarten Beek]

Hi all,

I get the following warning when using ICP:

vtkMath::Jacobi: Error extracting eigenfunctions

It comes from vtkMath::vtkJacobiN that calculates the eigenvalues, -vectors of a matrix.
The function returns 0, when this error occurs (otherwise 1), but vtkLandmarkTransform doesn't check for the return value and thus uses undefined values for the eigenvalues, -vectors.
This means my point set becomes invalid.
I believe the way to avoid this error is to 'giggle' the coordinates a little when it happens, but how can I intervene when vtkLandmarkTransform stubbornly uses whatever values it gets from vtkMath::vtkJacobiN?
Is there a way to intercept the error message?

I also noticed that if I apply ICP on A and B1 resulting in the error message, applying ICP on A and B2 (loading the same data file that gives me B1) works fine. I don't see vtkMath::vtkJacobiN using a random number or doing something similar, which makes me believe the error message I get is due to floating point accuracy? Even more a reason to think that 'giggling' might work (if I were able to intervene before the invalid transform is applied to my data...)


Thanks - Maarten
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