IMPLEMENTATION: Step 23x3 Matrix to a Real Schur Form
For all pairs (k,m) in a sweep do:
- For each triple i = k, k+1 do
- Set B = A[i,m,m+1]
- Find a real eigenvalue ? for B
- Find an eigenvector x such that B x = ? x
- Find a 3D orthogonal matrix Q such that the pivot elements in QT A Q are zero.
- Complete the update QT A Q