pcl_reduce_traits.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__PCL_reduce_traits
#define __H__PCL_reduce_traits
 
#include <algorithm>
 
namespace pcl {
  
 
template <class TValue>
struct reduce_traits
{
  typedef TValue value_t;
  static inline value_t min(value_t v1, value_t v2) {return std::min(v1, v2);}
  static inline value_t max(value_t v1, value_t v2) {return std::max(v1, v2);}
  static inline value_t sum(value_t v1, value_t v2) {return v1 + v2;}
  static inline value_t prod(value_t v1, value_t v2)  {return v1 * v2;}
  static inline value_t land(value_t v1, value_t v2)  {return v1 && v2;}
  static inline value_t band(value_t v1, value_t v2)  {return v1 & v2;}
  static inline value_t lor(value_t v1, value_t v2) {return v1 || v2;}
  static inline value_t bor(value_t v1, value_t v2) {return v1 | v2;}
};
 
template <>
struct reduce_traits<float>
{
  typedef float value_t;
  static inline value_t min(value_t v1, value_t v2) {return std::min(v1, v2);}
  static inline value_t max(value_t v1, value_t v2) {return std::max(v1, v2);}
  static inline value_t sum(value_t v1, value_t v2) {return v1 + v2;}
  static inline value_t prod(value_t v1, value_t v2)  {return v1 * v2;}
  static inline value_t land(value_t v1, value_t v2)  {return v1 && v2;}
  static inline value_t band(value_t v1, value_t v2)  {UG_THROW("floats do not support a binary and operation.");}
  static inline value_t lor(value_t v1, value_t v2) {return v1 || v2;}
  static inline value_t bor(value_t v1, value_t v2) {UG_THROW("floats do not support a binary or operation.");}
};
 
template <>
struct reduce_traits<double>
{
  typedef double value_t;
  static inline value_t min(value_t v1, value_t v2) {return std::min(v1, v2);}
  static inline value_t max(value_t v1, value_t v2) {return std::max(v1, v2);}
  static inline value_t sum(value_t v1, value_t v2) {return v1 + v2;}
  static inline value_t prod(value_t v1, value_t v2)  {return v1 * v2;}
  static inline value_t land(value_t v1, value_t v2)  {return v1 && v2;}
  static inline value_t band(value_t v1, value_t v2)  {UG_THROW("doubles do not support a binary and operation.");}
  static inline value_t lor(value_t v1, value_t v2) {return v1 || v2;}
  static inline value_t bor(value_t v1, value_t v2) {UG_THROW("doubles do not support a binary or operation.");}
};
 
 
template <class T>
class Reducer {
public:
  Reducer (ReduceOperation rop)
  {
    if(rop == MPI_MIN)      m_op = &reduce_traits<T>::min;
    else if(rop == MPI_MAX)   m_op = &reduce_traits<T>::max;
    else if(rop == MPI_SUM)   m_op = &reduce_traits<T>::sum;
    else if(rop == MPI_PROD)  m_op = &reduce_traits<T>::prod;
    else if(rop == MPI_LAND)  m_op = &reduce_traits<T>::land;
    else if(rop == MPI_BAND)  m_op = &reduce_traits<T>::band;
    else if(rop == MPI_LOR)   m_op = &reduce_traits<T>::lor;
    else if(rop == MPI_BOR)   m_op = &reduce_traits<T>::bor;
    else {UG_THROW ("Unsupported reduce operation: " << rop)};
  }
 
  
  T operator () (T v1, T v2)  {return m_op (v1, v2);}
 
  T reduce (T v1, T v2) {return m_op (v1, v2);}
 
private:
  T (*m_op) (T, T);
};
 
 
 
}// end of namespace
 
#endif  //__H__PCL_reduce_traits