Contents
zungqr - generate an M-by-N complex matrix Q with orthonor-
mal columns,
SUBROUTINE ZUNGQR(M, N, K, A, LDA, TAU, WORKIN, LWORKIN, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORKIN(*)
INTEGER M, N, K, LDA, LWORKIN, INFO
SUBROUTINE ZUNGQR_64(M, N, K, A, LDA, TAU, WORKIN, LWORKIN, INFO)
DOUBLE COMPLEX A(LDA,*), TAU(*), WORKIN(*)
INTEGER*8 M, N, K, LDA, LWORKIN, INFO
F95 INTERFACE
SUBROUTINE UNGQR(M, [N], [K], A, [LDA], TAU, [WORKIN], [LWORKIN],
[INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORKIN
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER :: M, N, K, LDA, LWORKIN, INFO
SUBROUTINE UNGQR_64(M, [N], [K], A, [LDA], TAU, [WORKIN], [LWORKIN],
[INFO])
COMPLEX(8), DIMENSION(:) :: TAU, WORKIN
COMPLEX(8), DIMENSION(:,:) :: A
INTEGER(8) :: M, N, K, LDA, LWORKIN, INFO
C INTERFACE
#include <sunperf.h>
void zungqr(int m, int n, int k, doublecomplex *a, int lda,
doublecomplex *tau, int *info);
void zungqr_64(long m, long n, long k, doublecomplex *a,
long lda, doublecomplex *tau, long *info);
zungqr generates an M-by-N complex matrix Q with orthonormal
columns, which is defined as the first N columns of a pro-
duct of K elementary reflectors of order M
Q = H(1) H(2) . . . H(k)
as returned by CGEQRF.
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 i-th column must contain the vector
which defines the elementary reflector H(i), for i
= 1,2,...,k, as returned by CGEQRF in the first k
columns 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 ele-
mentary reflector H(i), as returned by CGEQRF.
WORKIN (workspace)
On exit, if INFO = 0, WORKIN(1) returns the
optimal LWORKIN.
LWORKIN (input)
The dimension of the array WORKIN. LWORKIN >=
max(1,N). For optimum performance LWORKIN >=
N*NB, where NB is the optimal blocksize.
If LWORKIN = -1, then a workspace query is
assumed; the routine only calculates the optimal
size of the WORKIN array, returns this value as
the first entry of the WORKIN array, and no error
message related to LWORKIN is issued by XERBLA.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an ille-
gal value