/*************************************************************************************

    Grid physics library, www.github.com/paboyle/Grid 

    Source file: ./lib/algorithms/Preconditioner.h

    Copyright (C) 2015

Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>

    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 of the License, 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.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

    See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/*  END LEGAL */
#ifndef GRID_PRECONDITIONER_H
#define GRID_PRECONDITIONER_H

NAMESPACE_BEGIN(Grid);

template<class Field> using Preconditioner =  LinearFunction<Field> ;

/*
template<class Field> class Preconditioner :  public LinearFunction<Field> {
  using LinearFunction<Field>::operator();
  virtual void operator()(const Field &src, Field & psi)=0;
};
*/

template<class Field> class TrivialPrecon :  public Preconditioner<Field> { 
public:
  using Preconditioner<Field>::operator();
  virtual void operator()(const Field &src, Field & psi){
    psi = src;
  }
  TrivialPrecon(void){};
};

NAMESPACE_END(Grid);
#endif
