DORG2L(3)      LAPACK routine of NEC Numeric Library Collection      DORG2L(3)



NAME
       DORG2L

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



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)
                     M is INTEGER
                     The number of rows of the matrix Q. M >= 0.

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

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

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

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

           WORK      (output)
                     WORK is DOUBLE PRECISION array, dimension (N)

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



LAPACK routine                  31 October 2017                      DORG2L(3)