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// This file is part of ff3d - http://www.freefem.org/ff3d
// Copyright (C) 2001, 2002, 2003 Stphane Del Pino
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
// $Id: DiagPrecond.hpp,v 1.4 2007/05/20 23:02:49 delpinux Exp $
// This is very simple preconditioner: Diagonale of Operator.
#ifndef _DIAGPRECOND_HPP_
#define _DIAGPRECOND_HPP_
#include <TinyVector.hpp>
#include <TinyMatrix.hpp>
#include <Vector.hpp>
#include <Preconditioner.hpp>
/*!
\class DiagPrecond
This class implements a diagonal Preconditionner
\author Stphane Del Pino
*/
class DiagPrecond
: public Preconditioner
{
private:
//! Contains the diagonal matrix.
Vector<real_t> P;
//! The matrix which contains the diagonale.
const BaseMatrix& A;
public:
std::string name() const
{
return "diagonal";
}
//! Initializes the DiagPrecond.
void initializes()
{
Vector<real_t> diagonal(A.size());
A.getDiagonal(diagonal);
for (size_t i=0; i<A.size(); ++i) {
if (diagonal[i] != 0)
P[i] = 1./diagonal[i];
else
P[i] = 1.;
}
}
//! Computes \f$ z = P^{-1} r \f$.
void computes(const Vector<real_t>& r ,
Vector<real_t>& z) const
{
ASSERT ((P.size() == r.size())&&(P.size() == z.size()));
for (size_t i=0; i<P.size(); ++i) {
z[i] = P[i]*r[i];
}
}
//! Copy constructor.
DiagPrecond(const DiagPrecond& D)
: Preconditioner(D),
P(D.P),
A(D.A)
{
;
}
//! Constructs a DiagPrecond using the pdeSystem
DiagPrecond(const Problem& Pb,
const BaseMatrix& AA)
: Preconditioner(Pb, diagonale),
P(AA.size()),
A(AA)
{
;
}
//! Destructor.
~DiagPrecond()
{
;
}
};
#endif // _DIAGPRECOND_HPP_
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