zungql(3P) Sun Performance Library zungql(3P)NAMEzungql - generate an M-by-N complex matrix Q with orthonormal columns,
SYNOPSIS
SUBROUTINE ZUNGQL(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER M, N, K, LDA, LWORK, INFO
SUBROUTINE ZUNGQL_64(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER*8 M, N, K, LDA, LWORK, INFO
F95 INTERFACE
SUBROUTINE UNGQL(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK], [INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, LWORK, INFO
SUBROUTINE UNGQL_64(M, [N], [K], A, [LDA], TAU, [WORK], [LWORK],
[INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORK
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER(8) :: M, N, K, LDA, LWORK, INFO
C INTERFACE
#include <sunperf.h>
void zungql(int m, int n, int k, doublecomplex *a, int lda, doublecom‐
plex *tau, int *info);
void zungql_64(long m, long n, long k, doublecomplex *a, long lda, dou‐
blecomplex *tau, long *info);
PURPOSEzungql 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)
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK (input)
The dimension of the array WORK. LWORK >= max(1,N). For
optimum performance LWORK >= N*NB, where NB is the optimal
blocksize.
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.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value
6 Mar 2009 zungql(3P)
