cgelqf - compute an LQ factorization of a complex M-by-N matrix A
SUBROUTINE CGELQF( M, N, A, LDA, TAU, WORK, LDWORK, INFO) COMPLEX A(LDA,*), TAU(*), WORK(*) INTEGER M, N, LDA, LDWORK, INFO
SUBROUTINE CGELQF_64( M, N, A, LDA, TAU, WORK, LDWORK, INFO) COMPLEX A(LDA,*), TAU(*), WORK(*) INTEGER*8 M, N, LDA, LDWORK, INFO
SUBROUTINE GELQF( [M], [N], A, [LDA], TAU, [WORK], [LDWORK], [INFO]) COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A INTEGER :: M, N, LDA, LDWORK, INFO
SUBROUTINE GELQF_64( [M], [N], A, [LDA], TAU, [WORK], [LDWORK], * [INFO]) COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A INTEGER(8) :: M, N, LDA, LDWORK, INFO
#include <sunperf.h>
void cgelqf(int m, int n, complex *a, int lda, complex *tau, int *info);
void cgelqf_64(long m, long n, complex *a, long lda, complex *tau, long *info);
cgelqf computes an LQ factorization of a complex M-by-N matrix A: A = L * Q.
WORK(1)
returns the optimal LDWORK.
If LDWORK = -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 LDWORK is issued by XERBLA.
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
The matrix Q is represented as a product of elementary reflectors
Q = H(k)' . . . H(2)' H(1)', where k = min(m,n).
Each H(i)
has the form
H(i) = I - tau * v * v'
where tau is a complex scalar, and v is a complex vector with
v(1:i-1)
= 0 and v(i)
= 1; conjg(v(i+1:n))
is stored on exit in
A(i,i+1:n), and tau in TAU(i).