ESMF_DLARZ Subroutine

subroutine ESMF_DLARZ(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

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

\verbatim

ESMF_DLARZ applies a real elementary reflector H to a real M-by-N matrix C, from either the left or the right. H is represented in the form

  H = I - tau * v * v**T

where tau is a real scalar and v is a real vector.

If tau = 0, then H is taken to be the unit matrix.

H is a product of k elementary reflectors as returned by ESMF_DTZRZF. \endverbatim \param[in] SIDE \verbatim SIDE is CHARACTER*1 = ‘L’: form H * C = ‘R’: form C * H \endverbatim

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

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

\param[in] L \verbatim L is INTEGER The number of entries of the vector V containing the meaningful part of the Householder vectors. If SIDE = ‘L’, M >= L >= 0, if SIDE = ‘R’, N >= L >= 0. \endverbatim

\param[in] V \verbatim V is DOUBLE PRECISION array, dimension (1+(L-1)*abs(INCV)) The vector v in the representation of H as returned by ESMF_DTZRZF. V is not used if TAU = 0. \endverbatim

\param[in] INCV \verbatim INCV is INTEGER The increment between elements of v. INCV <> 0. \endverbatim

\param[in] TAU \verbatim TAU is DOUBLE PRECISION The value tau in the representation of H. \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 the matrix H * C if SIDE = ‘L’, or C * H if SIDE = ‘R’. \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 (N) if SIDE = ‘L’ or (M) if SIDE = ‘R’ \endverbatim \author Univ. of Tennessee \author Univ. of California Berkeley \author Univ. of Colorado Denver \author NAG Ltd. \date November 2011 \ingroup doubleOTHERcomputational \par Contributors:

A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA \par Further Details:

\verbatim \endverbatim

Arguments