zungr2(3P) Sun Performance Library zungr2(3P)NAMEzungr2 - generate an m by n complex matrix Q with orthonormal rows,
SYNOPSIS
SUBROUTINE ZUNGR2(M, N, K, A, LDA, TAU, WORK, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER M, N, K, LDA, INFO
SUBROUTINE ZUNGR2_64(M, N, K, A, LDA, TAU, WORK, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER*8 M, N, K, LDA, INFO
F95 INTERFACE
SUBROUTINE UNGR2([M], [N], [K], A, [LDA], TAU, [WORK], [INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, INFO
SUBROUTINE UNGR2_64([M], [N], [K], A, [LDA], TAU, [WORK], [INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER(8) :: M, N, K, LDA, INFO
C INTERFACE
#include <sunperf.h>
void zungr2(int m, int n, int k, doublecomplex *a, int lda, doublecom‐
plex *tau, int *info);
void zungr2_64(long m, long n, long k, doublecomplex *a, long lda, dou‐
blecomplex *tau, long *info);
PURPOSEzungr2 generates an m by n complex matrix Q with orthonormal rows,
which is defined as the last m rows of a product of k elementary
reflectors of order n
Q = H(1)' H(2)' . . . H(k)'
as returned by ZGERQF.
ARGUMENTS
M (input) The number of rows of the matrix Q. M >= 0.
N (input) The number of columns of the matrix Q. N >= M.
K (input) The number of elementary reflectors whose product defines the
matrix Q. M >= K >= 0.
A (input/output)
On entry, the (m-k+i)-th row must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by ZGERQF in the last k rows of its array argument
A. On exit, the m-by-n matrix Q.
LDA (input)
The first dimension of the array A. LDA >= max(1,M).
TAU (input)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by ZGERQF.
WORK (workspace)
dimension(M)
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value
6 Mar 2009 zungr2(3P)
