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132 lines
5.1 KiB
132 lines
5.1 KiB
/* -*- c++ -*- (enables emacs c++ mode) */
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/*===========================================================================
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Copyright (C) 2003-2012 Yves Renard
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This file is a part of GETFEM++
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Getfem++ is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version along with the GCC Runtime Library
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Exception either version 3.1 or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License and GCC Runtime Library Exception for more details.
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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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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As a special exception, you may use this file as it is a part of a free
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software library without restriction. Specifically, if other files
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instantiate templates or use macros or inline functions from this file,
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or you compile this file and link it with other files to produce an
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executable, this file does not by itself cause the resulting executable
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to be covered by the GNU Lesser General Public License. This exception
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does not however invalidate any other reasons why the executable file
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might be covered by the GNU Lesser General Public License.
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===========================================================================*/
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/**@file gmm_precond_diagonal.h
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@author Yves Renard <Yves.Renard@insa-lyon.fr>
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@date June 5, 2003.
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@brief Diagonal matrix preconditoner.
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*/
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#ifndef GMM_PRECOND_DIAGONAL_H
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#define GMM_PRECOND_DIAGONAL_H
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#include "gmm_precond.h"
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namespace gmm {
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/** Diagonal preconditioner. */
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template<typename Matrix> struct diagonal_precond {
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typedef typename linalg_traits<Matrix>::value_type value_type;
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typedef typename number_traits<value_type>::magnitude_type magnitude_type;
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std::vector<magnitude_type> diag;
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void build_with(const Matrix &M) {
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diag.resize(mat_nrows(M));
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for (size_type i = 0; i < mat_nrows(M); ++i) {
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magnitude_type x = gmm::abs(M(i, i));
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if (x == magnitude_type(0)) {
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x = magnitude_type(1);
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GMM_WARNING2("The matrix has a zero on its diagonal");
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}
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diag[i] = magnitude_type(1) / x;
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}
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}
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size_type memsize() const { return sizeof(*this) + diag.size() * sizeof(value_type); }
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diagonal_precond(const Matrix &M) { build_with(M); }
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diagonal_precond(void) {}
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};
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template <typename Matrix, typename V2> inline
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void mult_diag_p(const diagonal_precond<Matrix>& P, V2 &v2, abstract_sparse){
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typename linalg_traits<V2>::iterator it = vect_begin(v2),
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ite = vect_end(v2);
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for (; it != ite; ++it) *it *= P.diag[it.index()];
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}
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template <typename Matrix, typename V2> inline
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void mult_diag_p(const diagonal_precond<Matrix>& P,V2 &v2, abstract_skyline)
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{ mult_diag_p(P, v2, abstract_sparse()); }
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template <typename Matrix, typename V2> inline
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void mult_diag_p(const diagonal_precond<Matrix>& P, V2 &v2, abstract_dense){
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for (size_type i = 0; i < P.diag.size(); ++i) v2[i] *= P.diag[i];
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}
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template <typename Matrix, typename V1, typename V2> inline
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void mult(const diagonal_precond<Matrix>& P, const V1 &v1, V2 &v2) {
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GMM_ASSERT2(P.diag.size() == vect_size(v2),"dimensions mismatch");
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copy(v1, v2);
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mult_diag_p(P, v2, typename linalg_traits<V2>::storage_type());
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}
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template <typename Matrix, typename V1, typename V2> inline
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void transposed_mult(const diagonal_precond<Matrix>& P,const V1 &v1,V2 &v2) {
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mult(P, v1, v2);
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}
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// # define DIAG_LEFT_MULT_SQRT
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template <typename Matrix, typename V1, typename V2> inline
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void left_mult(const diagonal_precond<Matrix>& P, const V1 &v1, V2 &v2) {
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GMM_ASSERT2(P.diag.size() == vect_size(v2), "dimensions mismatch");
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copy(v1, v2);
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# ifdef DIAG_LEFT_MULT_SQRT
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for (size_type i= 0; i < P.diag.size(); ++i) v2[i] *= gmm::sqrt(P.diag[i]);
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# else
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for (size_type i= 0; i < P.diag.size(); ++i) v2[i] *= P.diag[i];
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# endif
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}
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template <typename Matrix, typename V1, typename V2> inline
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void transposed_left_mult(const diagonal_precond<Matrix>& P,
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const V1 &v1, V2 &v2)
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{ left_mult(P, v1, v2); }
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template <typename Matrix, typename V1, typename V2> inline
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void right_mult(const diagonal_precond<Matrix>& P, const V1 &v1, V2 &v2) {
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typedef typename linalg_traits<Matrix>::value_type T;
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GMM_ASSERT2(P.diag.size() == vect_size(v2), "dimensions mismatch");
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copy(v1, v2);
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# ifdef DIAG_LEFT_MULT_SQRT
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for (size_type i= 0; i < P.diag.size(); ++i) v2[i] *= gmm::sqrt(P.diag[i]);
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# endif
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}
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template <typename Matrix, typename V1, typename V2> inline
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void transposed_right_mult(const diagonal_precond<Matrix>& P,
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const V1 &v1, V2 &v2)
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{ right_mult(P, v1, v2); }
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}
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#endif
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