memreduce.h

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/*
 * Copyright (c) 2013-2017:  G-CSC, Goethe University Frankfurt
 * Author: Sebastian Reiter, Dmitry Logashenko
 * 
 * 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.
 */
 
/* ug4 headers */
#include "pcl/pcl.h"
#include "pcl/pcl_communication_structs.h"
#include "common/serialization.h"
 
#ifndef __H__UG__PLUGINS__ELECTROMAGNETISM__MEM_REDUCE__
#define __H__UG__PLUGINS__ELECTROMAGNETISM__MEM_REDUCE__
 
namespace ug{
namespace Electromagnetism{
 
template <typename TArray, typename TLayout, typename TOp>
class ComPol_MemOp : public pcl::ICommunicationPolicy<TLayout>
{
  typedef ComPol_MemOp<TArray, TLayout, TOp> this_type;
  typedef typename pcl::ICommunicationPolicy<TLayout> base_type;
  
public:
  typedef TArray array_type;
  typedef typename array_type::value_type value_type;
  typedef typename base_type::Layout Layout;
  typedef typename base_type::Interface Interface;
 
public:
  ComPol_MemOp () : m_pMemDst(NULL), m_pMemSrc(NULL) {}
 
  ComPol_MemOp (TArray* pVec): m_pMemDst(pVec), m_pMemSrc(pVec) {}
 
  ComPol_MemOp (TArray* pMemDst, const TArray* pMemSrc)
    : m_pMemDst(pMemDst), m_pMemSrc(pMemSrc) {}
 
  void set_src (const TArray* pMem) {m_pMemSrc = pMem;}
 
  void set_dst (TArray* pMemDst) {m_pMemDst = pMemDst;}
 
 
  virtual int get_required_buffer_size (const Interface& interface)
  {
    return interface.size () * sizeof (value_type);
  }
 
 
  virtual bool collect (ug::BinaryBuffer& buff, const Interface& interface)
  {
  //  check that vector has been set
    if (m_pMemSrc == NULL) return false;
 
  //  loop interface
    for (typename Interface::const_iterator iter = interface.begin ();
        iter != interface.end (); ++iter)
    {
    //  get index
      const size_t index = interface.get_element (iter);
 
    //  write entry into buffer
      Serialize (buff, (* m_pMemSrc) [index]);
    }
    return true;
  }
 
 
  virtual bool extract (ug::BinaryBuffer& buff, const Interface& interface)
  {
  //  check that vector has been set
    if(m_pMemDst == NULL) return false;
 
  //  loop interface
    for (typename Interface::const_iterator iter = interface.begin ();
        iter != interface.end (); ++iter)
    {
    //  get index
      const size_t index = interface.get_element (iter);
 
    //  write entry into the array
      typename TArray::value_type entry;
      Deserialize (buff, entry);
      (* m_pMemDst) [index] = TOp::op ((* m_pMemDst) [index], entry);
    }
    return true;
  }
 
private:
//  pointer to current vector
  TArray* m_pMemDst;
  const TArray* m_pMemSrc;
};
 
template <typename TArray, typename TLayout>
class ComPol_MemCopy : public pcl::ICommunicationPolicy<TLayout>
{
  typedef ComPol_MemCopy<TArray, TLayout> this_type;
  typedef typename pcl::ICommunicationPolicy<TLayout> base_type;
  
public:
  typedef TArray array_type;
  typedef typename array_type::value_type value_type;
  typedef typename base_type::Layout Layout;
  typedef typename base_type::Interface Interface;
 
public:
  ComPol_MemCopy () : m_pMemDst(NULL), m_pMemSrc(NULL) {}
 
  ComPol_MemCopy (TArray* pVec): m_pMemDst(pVec), m_pMemSrc(pVec) {}
 
  ComPol_MemCopy (TArray* pMemDst, const TArray* pMemSrc)
    : m_pMemDst(pMemDst), m_pMemSrc(pMemSrc) {}
 
  void set_src (const TArray* pMem) {m_pMemSrc = pMem;}
 
  void set_dst (TArray* pMemDst) {m_pMemDst = pMemDst;}
 
 
  virtual int get_required_buffer_size (const Interface& interface)
  {
    return interface.size () * sizeof (typename TArray::value_type);
  }
 
 
  virtual bool collect (ug::BinaryBuffer& buff, const Interface& interface)
  {
  //  check that vector has been set
    if (m_pMemSrc == NULL) return false;
 
  //  loop interface
    for (typename Interface::const_iterator iter = interface.begin ();
        iter != interface.end (); ++iter)
    {
    //  get index
      const size_t index = interface.get_element (iter);
 
    //  write entry into buffer
      Serialize (buff, (* m_pMemSrc) [index]);
    }
    return true;
  }
 
 
  virtual bool extract (ug::BinaryBuffer& buff, const Interface& interface)
  {
  //  check that vector has been set
    if(m_pMemDst == NULL) return false;
 
  //  loop interface
    for (typename Interface::const_iterator iter = interface.begin ();
        iter != interface.end (); ++iter)
    {
    //  get index
      const size_t index = interface.get_element (iter);
 
    //  write entry into array
      Deserialize (buff, (* m_pMemDst) [index]);
    }
    return true;
  }
 
private:
//  pointer to current vector
  TArray* m_pMemDst;
  const TArray* m_pMemSrc;
};
 
template <typename TArray, typename TLayout, typename TOp>
void MemAllReduce
(
  TArray* pMem, 
  const TLayout& masterLayout, 
  const TLayout& slaveLayout, 
  pcl::InterfaceCommunicator<TLayout>* pCom = NULL 
)
{
//  create a new communicator if required
  pcl::InterfaceCommunicator<TLayout> tCom;
  pcl::InterfaceCommunicator<TLayout>& com = (!pCom)? tCom : *pCom;
 
//  STEP 1: Reduce slave values on the master
 
  // create the required communication policies
  ComPol_MemOp<TArray, TLayout, TOp> cpMemOp (pMem);
 
  // perform communication
  com.send_data (slaveLayout, cpMemOp);
  com.receive_data (masterLayout, cpMemOp);
  com.communicate ();
  
//  STEP 2: copy master values to slaves
 
  // create the required communication policies
  ComPol_MemCopy<TArray, TLayout> cpMemCopy (pMem);
 
  // perform communication
  com.send_data (masterLayout, cpMemCopy);
  com.receive_data (slaveLayout, cpMemCopy);
  com.communicate ();
};
 
} // end namespace Electromagnetism
} // end namespace ug
 
#endif // __H__UG__PLUGINS__ELECTROMAGNETISM__MEM_REDUCE__
 
/* End of File */