161 lines
4.9 KiB
C
161 lines
4.9 KiB
C
/*BHEADER**********************************************************************
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* Copyright (c) 2006 The Regents of the University of California.
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* Produced at the Lawrence Livermore National Laboratory.
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* Written by the HYPRE team. UCRL-CODE-222953.
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* All rights reserved.
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*
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* This file is part of HYPRE (see http://www.llnl.gov/CASC/hypre/).
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* Please see the COPYRIGHT_and_LICENSE file for the copyright notice,
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* disclaimer, contact information and the GNU Lesser General Public License.
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*
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* HYPRE is free software; you can redistribute it and/or modify it under the
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* terms of the GNU General Public License (as published by the Free Software
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* Foundation) version 2.1 dated February 1999.
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*
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* HYPRE is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the IMPLIED WARRANTY OF MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the terms and conditions of the GNU General
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* Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* $Revision$
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***********************************************************************EHEADER*/
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#include "../blas/hypre_blas.h"
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#include "hypre_lapack.h"
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#include "f2c.h"
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/* Subroutine */ int dlarf_(char *side, integer *m, integer *n, doublereal *v,
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integer *incv, doublereal *tau, doublereal *c__, integer *ldc,
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doublereal *work)
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{
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/* -- LAPACK auxiliary routine (version 3.0) --
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Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
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Courant Institute, Argonne National Lab, and Rice University
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February 29, 1992
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Purpose
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=======
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DLARF applies a real elementary reflector H to a real m by n matrix
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C, from either the left or the right. H is represented in the form
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H = I - tau * v * v'
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where tau is a real scalar and v is a real vector.
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If tau = 0, then H is taken to be the unit matrix.
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Arguments
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=========
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SIDE (input) CHARACTER*1
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= 'L': form H * C
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= 'R': form C * H
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M (input) INTEGER
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The number of rows of the matrix C.
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N (input) INTEGER
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The number of columns of the matrix C.
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V (input) DOUBLE PRECISION array, dimension
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(1 + (M-1)*abs(INCV)) if SIDE = 'L'
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or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
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The vector v in the representation of H. V is not used if
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TAU = 0.
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INCV (input) INTEGER
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The increment between elements of v. INCV <> 0.
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TAU (input) DOUBLE PRECISION
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The value tau in the representation of H.
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C (input/output) DOUBLE PRECISION array, dimension (LDC,N)
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On entry, the m by n matrix C.
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On exit, C is overwritten by the matrix H * C if SIDE = 'L',
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or C * H if SIDE = 'R'.
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LDC (input) INTEGER
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The leading dimension of the array C. LDC >= max(1,M).
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WORK (workspace) DOUBLE PRECISION array, dimension
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(N) if SIDE = 'L'
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or (M) if SIDE = 'R'
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=====================================================================
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Parameter adjustments */
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/* Table of constant values */
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static doublereal c_b4 = 1.;
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static doublereal c_b5 = 0.;
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static integer c__1 = 1;
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/* System generated locals */
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integer c_dim1, c_offset;
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doublereal d__1;
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/* Local variables */
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extern /* Subroutine */ int dger_(integer *, integer *, doublereal *,
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doublereal *, integer *, doublereal *, integer *, doublereal *,
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integer *);
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extern logical lsame_(char *, char *);
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extern /* Subroutine */ int dgemv_(char *, integer *, integer *,
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doublereal *, doublereal *, integer *, doublereal *, integer *,
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doublereal *, doublereal *, integer *);
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--v;
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c_dim1 = *ldc;
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c_offset = 1 + c_dim1 * 1;
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c__ -= c_offset;
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--work;
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/* Function Body */
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if (lsame_(side, "L")) {
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/* Form H * C */
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if (*tau != 0.) {
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/* w := C' * v */
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dgemv_("Transpose", m, n, &c_b4, &c__[c_offset], ldc, &v[1], incv,
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&c_b5, &work[1], &c__1);
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/* C := C - v * w' */
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d__1 = -(*tau);
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dger_(m, n, &d__1, &v[1], incv, &work[1], &c__1, &c__[c_offset],
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ldc);
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}
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} else {
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/* Form C * H */
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if (*tau != 0.) {
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/* w := C * v */
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dgemv_("No transpose", m, n, &c_b4, &c__[c_offset], ldc, &v[1],
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incv, &c_b5, &work[1], &c__1);
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/* C := C - w * v' */
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d__1 = -(*tau);
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dger_(m, n, &d__1, &work[1], &c__1, &v[1], incv, &c__[c_offset],
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ldc);
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}
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}
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return 0;
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/* End of DLARF */
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} /* dlarf_ */
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