dorg2l(3F)

NAME
     DORG2L - generate an m by n real matrix Q with orthonormal columns,

SYNOPSIS
     SUBROUTINE DORG2L( M, N, K, A, LDA, TAU, WORK, INFO )

         INTEGER        INFO, K, LDA, M, N

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

PURPOSE
     DORG2L generates an m by n real matrix Q with orthonormal columns, which
     is defined as the last n columns of a product of k elementary reflectors
     of order m

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

     as returned by DGEQLF.


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 (n-k+i)-th column must contain the vector which
             defines the elementary reflector H(i), for i = 1,2,...,k, as
             returned by DGEQLF in the last 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 DGEQLF.

     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