raster_kernels.h

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/*
 * Copyright (c) 2017:  G-CSC, Goethe University Frankfurt
 * Author: Sebastian Reiter
 * 
 * This file is part of UG4.
 * 
 * UG4 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 3 (as published by the
 * Free Software Foundation) with the following additional attribution
 * requirements (according to LGPL/GPL v3 §7):
 * 
 * (1) The following notice must be displayed in the Appropriate Legal Notices
 * of covered and combined works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (2) The following notice must be displayed at a prominent place in the
 * terminal output of covered works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (3) The following bibliography is recommended for citation and must be
 * preserved in all covered files:
 * "Reiter, S., Vogel, A., Heppner, I., Rupp, M., and Wittum, G. A massively
 *   parallel geometric multigrid solver on hierarchically distributed grids.
 *   Computing and visualization in science 16, 4 (2013), 151-164"
 * "Vogel, A., Reiter, S., Rupp, M., Nägel, A., and Wittum, G. UG4 -- a novel
 *   flexible software system for simulating pde based models on high performance
 *   computers. Computing and visualization in science 16, 4 (2013), 165-179"
 * 
 * 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 Lesser General Public License for more details.
 */
 
#ifndef __H__UG_raster_kernels
#define __H__UG_raster_kernels
 
#include "raster.h"
 
namespace ug {
namespace raster_kernels {
 
 
template <class T, int TDIM>
class Count {
public:
  typedef size_t result_t;
 
  Count () :
    m_count (0)
  {}
 
  inline void operator () (Raster<T, TDIM>& raster,
               const typename Raster<T, TDIM>::MultiIndex& cur)
  {
    if(raster.node_value(cur) != raster.no_data_value())
      ++m_count;
  }
 
  inline size_t result() const
  {return m_count;}
 
private:
  size_t m_count;
};
 
 
 
template <class T, int TDIM>
class Sum {
public:
  typedef T result_t;
 
  Sum () :
    m_sum (0)
  {}
 
  inline void operator () (Raster<T, TDIM>& raster,
               const typename Raster<T, TDIM>::MultiIndex& cur)
  {
    if(raster.node_value(cur) != raster.no_data_value())
      m_sum += raster.node_value(cur);
  }
 
  inline T result() const
  {return m_sum;}
 
private:
  T m_sum;
};
 
 
 
template <class T, int TDIM>
class Blur {
public:
  Blur (T alpha) :
    m_alpha (alpha)
  {}
 
  void operator () (Raster<T, TDIM>& raster,
                  const typename Raster<T, TDIM>::MultiIndex& cur)
  {
    if(raster.node_value(cur) != raster.no_data_value()) {
      T numNbrs = (T)raster.template run_on_nbrs<Count<T, TDIM> >(cur);
      if(numNbrs) {
        T nbrVal = raster.template run_on_nbrs<Sum<T, TDIM> >(cur);
        
        raster.node_value(cur) = raster.node_value(cur) * (1. - m_alpha)
                     + (nbrVal * m_alpha / numNbrs);
      }
    }
  }
 
private:
  T m_alpha;
};
 
}// end of namespace
}// end of namespace
 
#endif  //__H__UG_raster_kernels