cgelq2 (3p)

Name

cgelq2 - compute the LQ factorization of a general rectangular matrix using an unblocked algorithm

Synopsis

SUBROUTINE CGELQ2(M, N, A, LDA, TAU, WORK, INFO)


INTEGER INFO, LDA, M, N

COMPLEX A(LDA,*), TAU(*), WORK(*)


SUBROUTINE CGELQ2_64(M, N, A, LDA, TAU, WORK, INFO)


INTEGER*8 INFO, LDA, M, N

COMPLEX A(LDA,*), TAU(*), WORK(*)


F95 INTERFACE
SUBROUTINE GELQ2(M, N, A, LDA, TAU, WORK, INFO)


INTEGER :: M, N, LDA, INFO

COMPLEX, DIMENSION(:) :: TAU, WORK

COMPLEX, DIMENSION(:,:) :: A


SUBROUTINE GELQ2_64(M, N, A, LDA, TAU, WORK, INFO)


INTEGER(8) :: M, N, LDA, INFO

COMPLEX, DIMENSION(:) :: TAU, WORK

COMPLEX, DIMENSION(:,:) :: A


C INTERFACE
#include <sunperf.h>

void cgelq2 (int m, int n, floatcomplex *a, int lda, floatcomplex *tau,
int *info);


void cgelq2_64 (long m, long n, floatcomplex *a, long lda, floatcomplex
*tau, long *info);

Description

Oracle Solaris Studio Performance Library                           cgelq2(3P)



NAME
       cgelq2  -  compute the LQ factorization of a general rectangular matrix
       using an unblocked algorithm


SYNOPSIS
       SUBROUTINE CGELQ2(M, N, A, LDA, TAU, WORK, INFO)


       INTEGER INFO, LDA, M, N

       COMPLEX A(LDA,*), TAU(*), WORK(*)


       SUBROUTINE CGELQ2_64(M, N, A, LDA, TAU, WORK, INFO)


       INTEGER*8 INFO, LDA, M, N

       COMPLEX A(LDA,*), TAU(*), WORK(*)


   F95 INTERFACE
       SUBROUTINE GELQ2(M, N, A, LDA, TAU, WORK, INFO)


       INTEGER :: M, N, LDA, INFO

       COMPLEX, DIMENSION(:) :: TAU, WORK

       COMPLEX, DIMENSION(:,:) :: A


       SUBROUTINE GELQ2_64(M, N, A, LDA, TAU, WORK, INFO)


       INTEGER(8) :: M, N, LDA, INFO

       COMPLEX, DIMENSION(:) :: TAU, WORK

       COMPLEX, DIMENSION(:,:) :: A


   C INTERFACE
       #include <sunperf.h>

       void cgelq2 (int m, int n, floatcomplex *a, int lda, floatcomplex *tau,
                 int *info);


       void cgelq2_64 (long m, long n, floatcomplex *a, long lda, floatcomplex
                 *tau, long *info);


PURPOSE
       cgelq2 computes an LQ factorization of a  complex  m  by  n  matrix  A:
       A=L*Q.


ARGUMENTS
       M (input)
                 M is INTEGER
                 The number of rows of the matrix A. M >= 0.


       N (input)
                 N is INTEGER
                 The number of columns of the matrix A. N >= 0.


       A (input/output)
                 A is COMPLEX array, dimension (LDA,N)
                 On entry, the m by n matrix A.
                 On  exit, the elements on and below the diagonal of the array
                 contain the m by min(m,n) lower trapezoidal matrix  L  (L  is
                 lower triangular if m <= n); the elements above the diagonal,
                 with the array TAU, represent the unitary matrix Q as a prod-
                 uct of elementary reflectors (see Further Details).


       LDA (input)
                 LDA is INTEGER
                 The leading dimension of the array A. LDA >= max(1,M).


       TAU (output)
                 TAU is COMPLEX array, dimension (min(M,N))
                 The  scalar factors of the elementary reflectors (see Further
                 Details).


       WORK (output)
                 WORK is COMPLEX array, dimension (M)


       INFO (output)
                 INFO is INTEGER
                 = 0: successful exit,
                 < 0: if INFO = -i, the i-th argument had an illegal value.


FURTHER DETAILS
       The matrix Q is represented as a product of elementary reflectors

       Q = H(k)**H . . . H(2)**H H(1)**H, where k = min(m,n).

       Each H(i) has the form

       H(i) = I - tau * v * v**H

       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).



                                  7 Nov 2015                        cgelq2(3P)