ESMF_DORG2R Subroutine

subroutine ESMF_DORG2R(M, N, K, A, LDA, TAU, WORK, INFO)

\brief \b ESMF_DORG2R generates all or part of the orthogonal matrix Q from a QR factorization determined by sgeqrf (unblocked algorithm). \htmlonly Download ESMF_DORG2R + dependencies [TGZ] [ZIP] [TXT] \endhtmlonly \par Purpose:

\verbatim

ESMF_DORG2R generates an m by n real matrix Q with orthonormal columns, which is defined as the first n columns of a product of k elementary reflectors of order m

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

as returned by ESMF_DGEQRF. \endverbatim \param[in] M \verbatim M is INTEGER The number of rows of the matrix Q. M >= 0. \endverbatim

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

\param[in] K \verbatim K is INTEGER The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0. \endverbatim

\param[in,out] A \verbatim A is DOUBLE PRECISION array, dimension (LDA,N) On entry, 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. On exit, the m-by-n matrix Q. \endverbatim

\param[in] LDA \verbatim LDA is INTEGER The first dimension of the array A. LDA >= max(1,M). \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[out] WORK \verbatim WORK is DOUBLE PRECISION array, dimension (N) \endverbatim

\param[out] INFO \verbatim INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument has 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