[vtkusers] PCA Problem

[Wenlong Wang]

Dear all.

I'm using vtkPCAStatistics to calculate the principle directions
(eigenvector) of two sets of 2D points. Then use the eigenvectors to compute
the angles between these two sets. The pointset1 is the target set and I'm
trying to rotate pointset2 with the same angle. I follow the steps in
http://www.vtk.org/Wiki/VTK/Examples/Cxx/Utilities/vtkPCAStatistics.

However, I found that when the angle is bigger than 45 degrees, the
direction of pointset2 goes to the opposite way it supposed to be.

Is that because of I missed any step in the calculation? Can anyone give me
some advice?

Thank you very much in advance.

Best wishes
Wenlong
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