• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

dorglq - generate an M-by-N real matrix Q with orthonormal rows,

SYNOPSIS

  SUBROUTINE DORGLQ( M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)
  INTEGER M, N, K, LDA, LDWORK, INFO
  DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)

  SUBROUTINE DORGLQ_64( M, N, K, A, LDA, TAU, WORK, LDWORK, INFO)
  INTEGER*8 M, N, K, LDA, LDWORK, INFO
  DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)

F95 INTERFACE

  SUBROUTINE ORGLQ( M, [N], [K], A, [LDA], TAU, [WORK], [LDWORK], 
 *       [INFO])
  INTEGER :: M, N, K, LDA, LDWORK, INFO
  REAL(8), DIMENSION(:) :: TAU, WORK
  REAL(8), DIMENSION(:,:) :: A

  SUBROUTINE ORGLQ_64( M, [N], [K], A, [LDA], TAU, [WORK], [LDWORK], 
 *       [INFO])
  INTEGER(8) :: M, N, K, LDA, LDWORK, INFO
  REAL(8), DIMENSION(:) :: TAU, WORK
  REAL(8), DIMENSION(:,:) :: A

C INTERFACE

#include <sunperf.h>

void dorglq(int m, int n, int k, double *a, int lda, double *tau, int *info);

void dorglq_64(long m, long n, long k, double *a, long lda, double *tau, long *info);

PURPOSE

dorglq generates an M-by-N real matrix Q with orthonormal rows, which is defined as the first M rows of a product of K elementary reflectors of order N

      Q  =  H(k) . . . H(2) H(1)

as returned by SGELQF.

ARGUMENTS

• M (input)
  The number of rows of the matrix Q. M > = 0.

• N (input)
  The number of columns of the matrix Q. N > = M.

• K (input)
  The number of elementary reflectors whose product defines the matrix Q. M > = K > = 0.

• A (input/output)
  On entry, the i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by SGELQF in the first k rows 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 elementary reflector H(i), as returned by SGELQF.

• WORK (workspace)
  On exit, if INFO = 0, WORK(1) returns the optimal LDWORK.

• LDWORK (input)
  The dimension of the array WORK. LDWORK > = max(1,M). For optimum performance LDWORK > = M*NB, where NB is the optimal blocksize.

  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.

• INFO (output)
  

   = 0:  successful exit

   < 0:  if INFO  = -i, the i-th argument has an illegal value