redhat man page for sorg2r

SORG2R(l)								 )								 SORG2R(l)

NAME
       SORG2R - generate an m by n real matrix Q with orthonormal columns,

SYNOPSIS
       SUBROUTINE SORG2R( M, N, K, A, LDA, TAU, WORK, INFO )

	   INTEGER	  INFO, K, LDA, M, N

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

PURPOSE
       SORG2R  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 SGEQRF.

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) REAL 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
	       SGEQRF 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) REAL array, dimension (K)
	       TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGEQRF.

       WORK    (workspace) REAL 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 							 SORG2R(l)