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ok_computer July 10, 2012 06:36

Eigenvalues in posdat.f
 
Hello,

anybody want to share coding on how to calculate the eigenvalues in posdat.f from a 3x3 matrix.

Namely I want to plot the Lambda 2 values and for that I have the definition as S_ij**2 + O_ij**2 ,where S_ij=0.5(dui/dxj+duj/dxi) and O_ij=0.5(dui/dxj - duj/dxi).
Lambda 2 is the second eigenvalue of the matrix but it is somewhat difficult to calculate.


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