ZUNG2L(3)      LAPACK routine of NEC Numeric Library Collection      ZUNG2L(3)



NAME
       ZUNG2L

SYNOPSIS
       SUBROUTINE ZUNG2L (M, N, K, A, LDA, TAU, WORK, INFO)



PURPOSE
            ZUNG2L generates an m by n complex 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 ZGEQLF.




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 COMPLEX*16 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 ZGEQLF 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 COMPLEX*16 array, dimension (K)
                     TAU(i) must contain the scalar factor of the elementary
                     reflector H(i), as returned by ZGEQLF.

           WORK      (output)
                     WORK is COMPLEX*16 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                      ZUNG2L(3)