CUNM2L(3)      LAPACK routine of NEC Numeric Library Collection      CUNM2L(3)



NAME
       CUNM2L

SYNOPSIS
       SUBROUTINE CUNM2L (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK,
           INFO)



PURPOSE
            CUNM2L overwrites the general complex m-by-n matrix C with

                  Q * C  if SIDE = 'L' and TRANS = 'N', or

                  Q**H* C  if SIDE = 'L' and TRANS = 'C', or

                  C * Q  if SIDE = 'R' and TRANS = 'N', or

                  C * Q**H if SIDE = 'R' and TRANS = 'C',

            where Q is a complex unitary matrix defined as the product of k
            elementary reflectors

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

            as returned by CGEQLF. Q is of order m if SIDE = 'L' and of order n
            if SIDE = 'R'.




ARGUMENTS
           SIDE      (input)
                     SIDE is CHARACTER*1
                     = 'L': apply Q or Q**H from the Left
                     = 'R': apply Q or Q**H from the Right

           TRANS     (input)
                     TRANS is CHARACTER*1
                     = 'N': apply Q  (No transpose)
                     = 'C': apply Q**H (Conjugate transpose)

           M         (input)
                     M is INTEGER
                     The number of rows of the matrix C. M >= 0.

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

           K         (input)
                     K is INTEGER
                     The number of elementary reflectors whose product defines
                     the matrix Q.
                     If SIDE = 'L', M >= K >= 0;
                     if SIDE = 'R', N >= K >= 0.

           A         (input)
                     A is COMPLEX array, dimension (LDA,K)
                     The i-th column must contain the vector which defines the
                     elementary reflector H(i), for i = 1,2,...,k, as returned by
                     CGEQLF in the last k columns of its array argument A.
                     A is modified by the routine but restored on exit.

           LDA       (input)
                     LDA is INTEGER
                     The leading dimension of the array A.
                     If SIDE = 'L', LDA >= max(1,M);
                     if SIDE = 'R', LDA >= max(1,N).

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

           C         (input/output)
                     C is COMPLEX array, dimension (LDC,N)
                     On entry, the m-by-n matrix C.
                     On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.

           LDC       (input)
                     LDC is INTEGER
                     The leading dimension of the array C. LDC >= max(1,M).

           WORK      (output)
                     WORK is COMPLEX array, dimension
                                              (N) if SIDE = 'L',
                                              (M) if SIDE = 'R'

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



LAPACK routine                  31 October 2017                      CUNM2L(3)