Contents
zupgtr - generate a complex unitary matrix Q which is
defined as the product of n-1 elementary reflectors H(i) of
order n, as returned by CHPTRD using packed storage
SUBROUTINE ZUPGTR(UPLO, N, AP, TAU, Q, LDQ, WORK, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX AP(*), TAU(*), Q(LDQ,*), WORK(*)
INTEGER N, LDQ, INFO
SUBROUTINE ZUPGTR_64(UPLO, N, AP, TAU, Q, LDQ, WORK, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX AP(*), TAU(*), Q(LDQ,*), WORK(*)
INTEGER*8 N, LDQ, INFO
F95 INTERFACE
SUBROUTINE UPGTR(UPLO, [N], AP, TAU, Q, [LDQ], [WORK], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: AP, TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: Q
INTEGER :: N, LDQ, INFO
SUBROUTINE UPGTR_64(UPLO, [N], AP, TAU, Q, [LDQ], [WORK], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: AP, TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: Q
INTEGER(8) :: N, LDQ, INFO
C INTERFACE
#include <sunperf.h>
void zupgtr(char uplo, int n, doublecomplex *ap, doublecom-
plex *tau, doublecomplex *q, int ldq, int *info);
void zupgtr_64(char uplo, long n, doublecomplex *ap, doub-
lecomplex *tau, doublecomplex *q, long ldq, long
*info);
zupgtr generates a complex unitary matrix Q which is defined
as the product of n-1 elementary reflectors H(i) of order n,
as returned by CHPTRD using packed storage:
if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),
if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).
UPLO (input)
= 'U': Upper triangular packed storage used in
previous call to CHPTRD; = 'L': Lower triangular
packed storage used in previous call to CHPTRD.
N (input) The order of the matrix Q. N >= 0.
AP (input)
The vectors which define the elementary reflec-
tors, as returned by CHPTRD.
TAU (input)
TAU(i) must contain the scalar factor of the ele-
mentary reflector H(i), as returned by CHPTRD.
Q (output)
The N-by-N unitary matrix Q.
LDQ (input)
The leading dimension of the array Q. LDQ >=
max(1,N).
WORK (workspace)
dimension(N-1)
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an ille-
gal value