redhat man page for dorg2r

DORG2R(l)								 )								 DORG2R(l)

NAME
       DORG2R - generate an m by n real matrix Q with orthonormal columns,

SYNOPSIS
       SUBROUTINE DORG2R( M, N, K, A, LDA, TAU, WORK, INFO )

	   INTEGER	  INFO, K, LDA, M, N

	   DOUBLE	  PRECISION A( LDA, * ), TAU( * ), WORK( * )

PURPOSE
       DORG2R  generates  an  m  by n real matrix Q with orthonormal columns, which is defined as the first n columns of a product of k elementary
       reflectors of order m

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

       as returned by DGEQRF.

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

       N       (input) INTEGER
	       The number of columns of the matrix Q. M >= N >= 0.

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

       A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
	       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
	       DGEQRF in the first k columns of its array argument A.  On exit, the m-by-n matrix Q.

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

       TAU     (input) DOUBLE PRECISION array, dimension (K)
	       TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGEQRF.

       WORK    (workspace) DOUBLE PRECISION array, dimension (N)

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

LAPACK version 3.0						   15 June 2000 							 DORG2R(l)