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dorm2l

 NAME
      DORM2L - overwrite the general real m by n matrix C with   Q
      * C if SIDE = 'L' and TRANS = 'N', or   Q'* C if SIDE = 'L'
      and TRANS = 'T', or   C * Q if SIDE = 'R' and TRANS = 'N',
      or   C * Q' if SIDE = 'R' and TRANS = 'T',

 SYNOPSIS
      SUBROUTINE DORM2L( SIDE, TRANS, M, N, K, A, LDA, TAU, C,
                         LDC, WORK, INFO )

          CHARACTER      SIDE, TRANS

          INTEGER        INFO, K, LDA, LDC, M, N

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

 PURPOSE
      DORM2L overwrites the general real m by n matrix C with

      where Q is a real orthogonal matrix defined as the product
      of k elementary reflectors

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

      as returned by DGEQLF. 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' from the Left
              = 'R': apply Q or Q' from the Right

      TRANS   (input) CHARACTER*1
              = 'N': apply Q  (No transpose)
              = 'T': apply Q' (Transpose)

      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) DOUBLE PRECISION 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 DGEQLF in the last k
              columns 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.  If SIDE =
              'L', LDA >= max(1,M); if SIDE = 'R', LDA >=
              max(1,N).

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

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

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

      WORK    (workspace) DOUBLE PRECISION array, dimension
              (N) if SIDE = 'L', (M) if SIDE = 'R'

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