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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
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subroutine ztgexc | ( | logical | WANTQ, |
logical | WANTZ, | ||
integer | N, | ||
complex*16, dimension( lda, * ) | A, | ||
integer | LDA, | ||
complex*16, dimension( ldb, * ) | B, | ||
integer | LDB, | ||
complex*16, dimension( ldq, * ) | Q, | ||
integer | LDQ, | ||
complex*16, dimension( ldz, * ) | Z, | ||
integer | LDZ, | ||
integer | IFST, | ||
integer | ILST, | ||
integer | INFO | ||
) |
ZTGEXC
Download ZTGEXC + dependencies [TGZ] [ZIP] [TXT]
ZTGEXC reorders the generalized Schur decomposition of a complex matrix pair (A,B), using an unitary equivalence transformation (A, B) := Q * (A, B) * Z**H, so that the diagonal block of (A, B) with row index IFST is moved to row ILST. (A, B) must be in generalized Schur canonical form, that is, A and B are both upper triangular. Optionally, the matrices Q and Z of generalized Schur vectors are updated. Q(in) * A(in) * Z(in)**H = Q(out) * A(out) * Z(out)**H Q(in) * B(in) * Z(in)**H = Q(out) * B(out) * Z(out)**H
[in] | WANTQ | WANTQ is LOGICAL .TRUE. : update the left transformation matrix Q; .FALSE.: do not update Q. |
[in] | WANTZ | WANTZ is LOGICAL .TRUE. : update the right transformation matrix Z; .FALSE.: do not update Z. |
[in] | N | N is INTEGER The order of the matrices A and B. N >= 0. |
[in,out] | A | A is COMPLEX*16 array, dimension (LDA,N) On entry, the upper triangular matrix A in the pair (A, B). On exit, the updated matrix A. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). |
[in,out] | B | B is COMPLEX*16 array, dimension (LDB,N) On entry, the upper triangular matrix B in the pair (A, B). On exit, the updated matrix B. |
[in] | LDB | LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). |
[in,out] | Q | Q is COMPLEX*16 array, dimension (LDZ,N) On entry, if WANTQ = .TRUE., the unitary matrix Q. On exit, the updated matrix Q. If WANTQ = .FALSE., Q is not referenced. |
[in] | LDQ | LDQ is INTEGER The leading dimension of the array Q. LDQ >= 1; If WANTQ = .TRUE., LDQ >= N. |
[in,out] | Z | Z is COMPLEX*16 array, dimension (LDZ,N) On entry, if WANTZ = .TRUE., the unitary matrix Z. On exit, the updated matrix Z. If WANTZ = .FALSE., Z is not referenced. |
[in] | LDZ | LDZ is INTEGER The leading dimension of the array Z. LDZ >= 1; If WANTZ = .TRUE., LDZ >= N. |
[in] | IFST | IFST is INTEGER |
[in,out] | ILST | ILST is INTEGER Specify the reordering of the diagonal blocks of (A, B). The block with row index IFST is moved to row ILST, by a sequence of swapping between adjacent blocks. |
[out] | INFO | INFO is INTEGER =0: Successful exit. <0: if INFO = -i, the i-th argument had an illegal value. =1: The transformed matrix pair (A, B) would be too far from generalized Schur form; the problem is ill- conditioned. (A, B) may have been partially reordered, and ILST points to the first row of the current position of the block being moved. |
Definition at line 202 of file ztgexc.f.