Computes the eigenvalues and Schur factorization of a general matrix, and orders the factorization so that selected eigenvalues are at the top left of the Schur form.
The routine computes for an
nreal/complex nonsymmetric matrix
A, the eigenvalues, the real Schur form
T, and, optionally, the matrix of Schur vectors
Z. This gives the Schur factorization
Optionally, it also orders the eigenvalues on the diagonal of the real-Schur/Schur form so that selected eigenvalues are at the top left. The leading columns of
Zthen form an orthonormal basis for the invariant subspace corresponding to the selected eigenvalues.
A real matrix is in real-Schur form if it is upper quasi-triangular with 1-by-1 and 2-by-2 blocks. 2-by-2 blocks will be standardized in the form
. The eigenvalues of such a block are
A complex matrix is in Schur form if it is upper triangular.
- Must beCHARACTER*1.'N'or'V'.If, then Schur vectors are not computed.jobvs='N'If, then Schur vectors are computed.jobvs='V'