DORMR2(3)      LAPACK routine of NEC Numeric Library Collection      DORMR2(3)



NAME
       DORMR2

SYNOPSIS
       SUBROUTINE DORMR2 (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK,
           INFO)



PURPOSE
            DORMR2 overwrites the general real m by n matrix C with

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

                  Q**T* C  if SIDE = 'L' and TRANS = 'T', or

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

                  C * Q**T if SIDE = 'R' and TRANS = 'T',

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

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

            as returned by DGERQF. 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**T from the Left
                     = 'R': apply Q or Q**T from the Right

           TRANS     (input)
                     TRANS is CHARACTER*1
                     = 'N': apply Q  (No transpose)
                     = 'T': apply Q' (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 DOUBLE PRECISION 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
                     DGERQF in the last k rows 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. LDA >= max(1,K).

           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 DGERQF.

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

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

           WORK      (output)
                     WORK is DOUBLE PRECISION 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                      DORMR2(3)