dorgr2(3F)

NAME
     DORGR2 - generate an m by n real matrix Q with orthonormal rows,

SYNOPSIS
     SUBROUTINE DORGR2( M, N, K, A, LDA, TAU, WORK, INFO )

         INTEGER        INFO, K, LDA, M, N

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

PURPOSE
     DORGR2 generates an m by n real matrix Q with orthonormal rows, which is
     defined as the last m rows of a product of k elementary reflectors of
     order n

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

     as returned by DGERQF.


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. N >= M.

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

     A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
             On entry, the (m-k+i)-th row must contain the vector which
             defines the elementary reflector H(i), for i = 1,2,...,k, as
             returned by DGERQF in the last k rows 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 DGERQF.

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

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