ctrexc
ctrexc - reorder the Schur factorization of a complex matrix A = Q*T*Q**H, so that the diagonal element of T with row index IFST is moved to row ILST
SUBROUTINE CTREXC( COMPQ, N, T, LDT, Q, LDQ, IFST, ILST, INFO)
CHARACTER * 1 COMPQ
COMPLEX T(LDT,*), Q(LDQ,*)
INTEGER N, LDT, LDQ, IFST, ILST, INFO
SUBROUTINE CTREXC_64( COMPQ, N, T, LDT, Q, LDQ, IFST, ILST, INFO)
CHARACTER * 1 COMPQ
COMPLEX T(LDT,*), Q(LDQ,*)
INTEGER*8 N, LDT, LDQ, IFST, ILST, INFO
SUBROUTINE TREXC( COMPQ, [N], T, [LDT], Q, [LDQ], IFST, ILST, [INFO])
CHARACTER(LEN=1) :: COMPQ
COMPLEX, DIMENSION(:,:) :: T, Q
INTEGER :: N, LDT, LDQ, IFST, ILST, INFO
SUBROUTINE TREXC_64( COMPQ, [N], T, [LDT], Q, [LDQ], IFST, ILST,
* [INFO])
CHARACTER(LEN=1) :: COMPQ
COMPLEX, DIMENSION(:,:) :: T, Q
INTEGER(8) :: N, LDT, LDQ, IFST, ILST, INFO
#include <sunperf.h>
void ctrexc(char compq, int n, complex *t, int ldt, complex *q, int ldq, int ifst, int ilst, int *info);
void ctrexc_64(char compq, long n, complex *t, long ldt, complex *q, long ldq, long ifst, long ilst, long *info);
ctrexc reorders the Schur factorization of a complex matrix
A = Q*T*Q**H, so that the diagonal element of T with row index IFST
is moved to row ILST.
The Schur form T is reordered by a unitary similarity transformation
Z**H*T*Z, and optionally the matrix Q of Schur vectors is updated by
postmultplying it with Z.
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* COMPQ (input)
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* N (input)
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The order of the matrix T. N >= 0.
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* T (input/output)
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On entry, the upper triangular matrix T.
On exit, the reordered upper triangular matrix.
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* LDT (input)
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The leading dimension of the array T. LDT >= max(1,N).
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* Q (input)
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On entry, if COMPQ = 'V', the matrix Q of Schur vectors.
On exit, if COMPQ = 'V', Q has been postmultiplied by the
unitary transformation matrix Z which reorders T.
If COMPQ = 'N', Q is not referenced.
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* LDQ (input)
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The leading dimension of the array Q. LDQ >= max(1,N).
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* IFST (input)
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Specify the reordering of the diagonal elements of T:
The element with row index IFST is moved to row ILST by a
sequence of transpositions between adjacent elements.
1 <= IFST <= N; 1 <= ILST <= N.
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* ILST (input)
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See the description of IFST.
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* INFO (output)
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