ESMF_DORMQL Subroutine

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

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

\verbatim

ESMF_DORMQL 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(k) . . . H(2) H(1)

as returned by DGEQLF. 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 DGEQLF in the last k columns of its array argument A. \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 DGEQLF. \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 good performance, LWORK should generally be larger.

     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 December 2016 \ingroup doubleOTHERcomputational

Arguments