          SUBROUTINE CUNMLQ( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC,
         $                   WORK, LWORK, INFO )
    *
    *  -- LAPACK routine (version 3.1) --
    *     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
    *     November 2006
    *
    *     .. Scalar Arguments ..
          CHARACTER          SIDE, TRANS
          INTEGER            INFO, K, LDA, LDC, LWORK, M, N
    *     ..
    *     .. Array Arguments ..
          COMPLEX            A( LDA, * ), C( LDC, * ), TAU( * ),
         $                   WORK( * )
    *     ..
    *
    *  Purpose
    *  =======
    *
    *  CUNMLQ overwrites the general complex M-by-N matrix C with
    *
    *                  SIDE = 'L'     SIDE = 'R'
    *  TRANS = 'N':      Q * C          C * Q
    *  TRANS = 'C':      Q**H * C       C * Q**H
    *
    *  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 CGELQF. Q is of order M if SIDE = 'L' and of order N
    *  if SIDE = 'R'.
    *
    *  Arguments
    *  =========
    *
    *  SIDE    (input) CHARACTER*1
    *          = 'L': apply Q or Q**H from the Left;
    *          = 'R': apply Q or Q**H from the Right.
    *
    *  TRANS   (input) CHARACTER*1
    *          = 'N':  No transpose, apply Q;
    *          = 'C':  Conjugate transpose, apply Q**H.
    *
    *  M       (input) INTEGER
    *          The number of rows of the matrix C. M >= 0.
    *
    *  N       (input) INTEGER
    *          The number of columns of the matrix C. N >= 0.
    *
    *  K       (input) 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) COMPLEX array, dimension
    *                               (LDA,M) if SIDE = 'L',
    *                               (LDA,N) if SIDE = 'R'
    *          The i-th row must contain the vector which defines the
    *          elementary reflector H(i), for i = 1,2,...,k, as returned by
    *          CGELQF in the first k rows of its array argument A.
    *          A is modified by the routine but restored on exit.
    *
    *  LDA     (input) INTEGER
    *          The leading dimension of the array A. LDA >= max(1,K).
    *
    *  TAU     (input) COMPLEX array, dimension (K)
    *          TAU(i) must contain the scalar factor of the elementary
    *          reflector H(i), as returned by CGELQF.
    *
    *  C       (input/output) 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) INTEGER
    *          The leading dimension of the array C. LDC >= max(1,M).
    *
    *  WORK    (workspace/output) COMPLEX array, dimension (MAX(1,LWORK))
    *          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
    *
    *  LWORK   (input) INTEGER
    *          The dimension of the array WORK.
    *          If SIDE = 'L', LWORK >= max(1,N);
    *          if SIDE = 'R', LWORK >= max(1,M).
    *          For optimum performance LWORK >= N*NB if SIDE 'L', and
    *          LWORK >= M*NB if SIDE = 'R', where NB is the optimal
    *          blocksize.
    *
    *          If LWORK = -1, then a workspace query is assumed; the routine
    *          only calculates the optimal size of the WORK array, returns
    *          this value as the first entry of the WORK array, and no error
    *          message related to LWORK is issued by XERBLA.
    *
    *  INFO    (output) INTEGER
    *          = 0:  successful exit
    *          < 0:  if INFO = -i, the i-th argument had an illegal value
    *
    *  =====================================================================
    *
    *     .. Parameters ..
          INTEGER            NBMAX, LDT
          PARAMETER          ( NBMAX = 64, LDT = NBMAX+1 )
    *     ..
    *     .. Local Scalars ..
          LOGICAL            LEFT, LQUERY, NOTRAN
          CHARACTER          TRANST
          INTEGER            I, I1, I2, I3, IB, IC, IINFO, IWS, JC, LDWORK,
         $                   LWKOPT, MI, NB, NBMIN, NI, NQ, NW
    *     ..
    *     .. Local Arrays ..
          COMPLEX            T( LDT, NBMAX )
    *     ..
    *     .. External Functions ..
          LOGICAL            LSAME
          INTEGER            ILAENV
          EXTERNAL           LSAME, ILAENV
    *     ..
    *     .. External Subroutines ..
          EXTERNAL           CLARFB, CLARFT, CUNML2, XERBLA
    *     ..
    *     .. Intrinsic Functions ..
          INTRINSIC          MAX, MIN
    *     ..
    *     .. Executable Statements ..
    *
    *     Test the input arguments
    *
          INFO = 0
          LEFT = LSAME( SIDE, 'L' )
          NOTRAN = LSAME( TRANS, 'N' )
          LQUERY = ( LWORK.EQ.-1 )
    *
    *     NQ is the order of Q and NW is the minimum dimension of WORK
    *
          IF( LEFT ) THEN
             NQ = M
             NW = N
          ELSE
             NQ = N
             NW = M
          END IF
          IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
             INFO = -1
          ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN
             INFO = -2
          ELSE IF( M.LT.0 ) THEN
             INFO = -3
          ELSE IF( N.LT.0 ) THEN
             INFO = -4
          ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
             INFO = -5
          ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
             INFO = -7
          ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
             INFO = -10
          ELSE IF( LWORK.LT.MAX( 1, NW ) .AND. .NOT.LQUERY ) THEN
             INFO = -12
          END IF
    *
          IF( INFO.EQ.0 ) THEN
    *
    *        Determine the block size.  NB may be at most NBMAX, where NBMAX
    *        is used to define the local array T.
    *
             NB = MIN( NBMAX, ILAENV( 1, 'CUNMLQ', SIDE // TRANS, M, N, K,
         $             -1 ) )
             LWKOPT = MAX( 1, NW )*NB
             WORK( 1 ) = LWKOPT
          END IF
    *
          IF( INFO.NE.0 ) THEN
             CALL XERBLA( 'CUNMLQ', -INFO )
             RETURN
          ELSE IF( LQUERY ) THEN
             RETURN
          END IF
    *
    *     Quick return if possible
    *
          IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 ) THEN
             WORK( 1 ) = 1
             RETURN
          END IF
    *
          NBMIN = 2
          LDWORK = NW
          IF( NB.GT.1 .AND. NB.LT.K ) THEN
             IWS = NW*NB
             IF( LWORK.LT.IWS ) THEN
                NB = LWORK / LDWORK
                NBMIN = MAX( 2, ILAENV( 2, 'CUNMLQ', SIDE // TRANS, M, N, K,
         $              -1 ) )
             END IF
          ELSE
             IWS = NW
          END IF
    *
          IF( NB.LT.NBMIN .OR. NB.GE.K ) THEN
    *
    *        Use unblocked code
    *
             CALL CUNML2( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK,
         $                IINFO )
          ELSE
    *
    *        Use blocked code
    *
             IF( ( LEFT .AND. NOTRAN ) .OR.
         $       ( .NOT.LEFT .AND. .NOT.NOTRAN ) ) THEN
                I1 = 1
                I2 = K
                I3 = NB
             ELSE
                I1 = ( ( K-1 ) / NB )*NB + 1
                I2 = 1
                I3 = -NB
             END IF
    *
             IF( LEFT ) THEN
                NI = N
                JC = 1
             ELSE
                MI = M
                IC = 1
             END IF
    *
             IF( NOTRAN ) THEN
                TRANST = 'C'
             ELSE
                TRANST = 'N'
             END IF
    *
             DO 10 I = I1, I2, I3
                IB = MIN( NB, K-I+1 )
    *
    *           Form the triangular factor of the block reflector
    *           H = H(i) H(i+1) . . . H(i+ib-1)
    *
                CALL CLARFT( 'Forward', 'Rowwise', NQ-I+1, IB, A( I, I ),
         $                   LDA, TAU( I ), T, LDT )
                IF( LEFT ) THEN
    *
    *              H or H' is applied to C(i:m,1:n)
    *
                   MI = M - I + 1
                   IC = I
                ELSE
    *
    *              H or H' is applied to C(1:m,i:n)
    *
                   NI = N - I + 1
                   JC = I
                END IF
    *
    *           Apply H or H'
    *
                CALL CLARFB( SIDE, TRANST, 'Forward', 'Rowwise', MI, NI, IB,
         $                   A( I, I ), LDA, T, LDT, C( IC, JC ), LDC, WORK,
         $                   LDWORK )
       10    CONTINUE
          END IF
          WORK( 1 ) = LWKOPT
          RETURN
    *
    *     End of CUNMLQ
    *
          END