numerics/preconditioner.h

// -*- c++ -*-

// +--------------------------------------------------------------------+
// | This file is part of MathTL - the Mathematical Template Library    |
// |                                                                    |
// | Copyright (c) 2002-2009                                            |
// | Thorsten Raasch, Manuel Werner                                     |
// +--------------------------------------------------------------------+

#ifndef _MATHTL_PRECONDITIONER_H
#define _MATHTL_PRECONDITIONER_H

#include <algebra/vector.h>

namespace MathTL
{
  template <class VECTOR>
  class Preconditioner
  {
  public:
    typedef typename VECTOR::size_type size_type;

    virtual ~Preconditioner() = 0;
    
    virtual const size_type row_dimension() const = 0;

    const size_type column_dimension() const { return row_dimension(); }

    virtual void apply(const VECTOR& x, VECTOR& Px) const = 0;

    virtual void apply_preconditioner(const VECTOR& Px, VECTOR& x) const = 0;
  };

  template <class MATRIX, class VECTOR>
  class IdentityPreconditioner
    : public Preconditioner<VECTOR>
  {
  public:
    typedef typename VECTOR::size_type size_type;

    IdentityPreconditioner(const MATRIX& A);

    const size_type row_dimension() const { return A.row_dimension(); }

    void apply(const VECTOR& x, VECTOR& Px) const;

    void apply_preconditioner(const VECTOR& Px, VECTOR& x) const;

  protected:
    const MATRIX& A;
  };

  template <class MATRIX, class VECTOR>
  class JacobiPreconditioner
    : public Preconditioner<VECTOR>
  {
  public:
    typedef typename VECTOR::size_type size_type;

    JacobiPreconditioner(const MATRIX& A);

    const size_type row_dimension() const { return A.row_dimension(); }

    void apply(const VECTOR& x, VECTOR& Px) const;

    void apply_preconditioner(const VECTOR& Px, VECTOR& x) const;

  protected:
    const MATRIX& A;
  };
}

#include <numerics/preconditioner.cpp>

#endif