zunghr - generate a complex unitary matrix Q which is defined as the product of IHI-ILO elementary reflectors of order N, as returned by CGEHRD
SUBROUTINE ZUNGHR( N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO) DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*) INTEGER N, ILO, IHI, LDA, LWORK, INFO
SUBROUTINE ZUNGHR_64( N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO) DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*) INTEGER*8 N, ILO, IHI, LDA, LWORK, INFO
SUBROUTINE UNGHR( [N], ILO, IHI, A, [LDA], TAU, [WORK], [LWORK], * [INFO]) COMPLEX(8), DIMENSION(:) :: TAU, WORK COMPLEX(8), DIMENSION(:,:) :: A INTEGER :: N, ILO, IHI, LDA, LWORK, INFO
SUBROUTINE UNGHR_64( [N], ILO, IHI, A, [LDA], TAU, [WORK], [LWORK], * [INFO]) COMPLEX(8), DIMENSION(:) :: TAU, WORK COMPLEX(8), DIMENSION(:,:) :: A INTEGER(8) :: N, ILO, IHI, LDA, LWORK, INFO
#include <sunperf.h>
void zunghr(int n, int ilo, int ihi, doublecomplex *a, int lda, doublecomplex *tau, int *info);
void zunghr_64(long n, long ilo, long ihi, doublecomplex *a, long lda, doublecomplex *tau, long *info);
zunghr generates a complex unitary matrix Q which is defined as the product of IHI-ILO elementary reflectors of order N, as returned by CGEHRD:
Q = H(ilo)
H(ilo+1)
. . . H(ihi-1).
TAU(i)
must contain the scalar factor of the elementary
reflector H(i), as returned by CGEHRD.
WORK(1)
returns the optimal LWORK.
If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA.
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value