T = schur(A)
T = schur(A,flag)
[U,T] = schur(A,...)
The schur command computes the Schur form of a matrix.
T is triangular and is complex if A is real and has complex eigenvalues.
T has the real eigenvalues on the diagonal and the complex eigenvalues in 2-by-2 blocks on the diagonal. 'real' is the default when A is real.
The function rsf2csf converts the real Schur form to the complex Schur form.
H is a 3-by-3 eigenvalue test matrix:
H = [ -149 -50 -154 537 180 546 -27 -9 -25 ]
Its Schur form is
schur(H) ans = 1.0000 -7.1119 -815.8706 0 2.0000 -55.0236 0 0 3.0000
The eigenvalues, which in this case are 1, 2, and 3, are on the diagonal. The fact that the off-diagonal elements are so large indicates that this matrix has poorly conditioned eigenvalues; small changes in the matrix elements produce relatively large changes in its eigenvalues.