ESMF_DORMQR Subroutine

subroutine ESMF_DORMQR(SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)

\brief \b ESMF_DORMQR \htmlonly Download ESMF_DORMQR + dependencies [TGZ] [ZIP] [TXT] \endhtmlonly \par Purpose:

\verbatim

ESMF_DORMQR overwrites the general real M-by-N matrix C with

            SIDE = 'L'     SIDE = 'R'

TRANS = ‘N’: Q * C C * Q TRANS = ‘T’: QT * C C * QT

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 ESMF_DGEQRF. Q is of order M if SIDE = ‘L’ and of order N if SIDE = ‘R’. \endverbatim \param[in] SIDE \verbatim SIDE is CHARACTER1 = ‘L’: apply Q or QT from the Left; = ‘R’: apply Q or Q*T from the Right. \endverbatim

\param[in] TRANS \verbatim TRANS is CHARACTER1 = ‘N’: No transpose, apply Q; = ‘T’: Transpose, apply Q*T. \endverbatim

\param[in] M \verbatim M is INTEGER The number of rows of the matrix C. M >= 0. \endverbatim

\param[in] N \verbatim N is INTEGER The number of columns of the matrix C. N >= 0. \endverbatim

\param[in] K \verbatim 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. \endverbatim

\param[in] A \verbatim A is 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 ESMF_DGEQRF in the first k columns of its array argument A. A is modified by the routine but restored on exit. \endverbatim

\param[in] LDA \verbatim LDA is INTEGER The leading dimension of the array A. If SIDE = ‘L’, LDA >= max(1,M); if SIDE = ‘R’, LDA >= max(1,N). \endverbatim

\param[in] TAU \verbatim TAU is DOUBLE PRECISION array, dimension (K) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ESMF_DGEQRF. \endverbatim

\param[in,out] C \verbatim C is DOUBLE PRECISION array, dimension (LDC,N) On entry, the M-by-N matrix C. On exit, C is overwritten by QC or QTC or CQT or CQ. \endverbatim

\param[in] LDC \verbatim LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M). \endverbatim

\param[out] WORK \verbatim WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. \endverbatim

\param[in] LWORK \verbatim LWORK is 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 >= NNB if SIDE = ‘L’, and LWORK >= MNB 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 ESMF_XERBLA.

\endverbatim

\param[out] INFO \verbatim INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value \endverbatim \author Univ. of Tennessee \author Univ. of California Berkeley \author Univ. of Colorado Denver \author NAG Ltd. \date November 2011 \ingroup doubleOTHERcomputational

Arguments