zung2l(3P) Sun Performance Library zung2l(3P)NAMEzung2l - generate an m by n complex matrix Q with orthonormal columns,
SYNOPSIS
SUBROUTINE ZUNG2L(M, N, K, A, LDA, TAU, WORK, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER M, N, K, LDA, INFO
SUBROUTINE ZUNG2L_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 UNG2L(M, [N], [K], A, [LDA], TAU, [WORK], [INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, INFO
SUBROUTINE UNG2L_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 zung2l(int m, int n, int k, doublecomplex *a, int lda, doublecom‐
plex *tau, int *info);
void zung2l_64(long m, long n, long k, doublecomplex *a, long lda, dou‐
blecomplex *tau, long *info);
PURPOSEzung2l L generates an m by n complex matrix Q with orthonormal columns,
which is defined as the last n columns of a product of k elementary
reflectors of order m
Q = H(k) . . . H(2)H(1)
as returned by ZGEQLF.
ARGUMENTS
M (input) The number of rows of the matrix Q. M >= 0.
N (input) The number of columns of the matrix Q. M >= N >= 0.
K (input) The number of elementary reflectors whose product defines the
matrix Q. N >= K >= 0.
A (input/output)
On entry, the (n-k+i)-th column must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by ZGEQLF in the last k columns of its array argu‐
ment 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 ZGEQLF.
WORK (workspace)
dimension(N)
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value
6 Mar 2009 zung2l(3P)
