ZYXTopology.h

// Copyright (C) 2015 Technische Universitaet Muenchen
// This file is part of the Mamico project. For conditions of distribution
// and use, please see the copyright notice in Mamico's main folder, or at
// www5.in.tum.de/mamico
#ifndef _MOLECULARDYNAMICS_COUPLING_PARALLELTOPOLOGY_ZYXTOPOLOGY_H_
#define _MOLECULARDYNAMICS_COUPLING_PARALLELTOPOLOGY_ZYXTOPOLOGY_H_
 
#include "coupling/CouplingMDDefinitions.h"
#include "coupling/paralleltopology/ParallelTopology.h"
 
namespace coupling {
namespace paralleltopology {
template <unsigned int dim> class ZYXTopology;
}
} // namespace coupling

template <unsigned int dim> class coupling::paralleltopology::ZYXTopology : public coupling::paralleltopology::ParallelTopology<dim> {
public:
  ZYXTopology(tarch::la::Vector<dim, unsigned int> numberProcesses)
      : coupling::paralleltopology::ParallelTopology<dim>(), _numberProcesses(numberProcesses),
        _divisionFactor4NumberProcesses(initDivisionFactor(numberProcesses)) {}

  virtual ~ZYXTopology() {}
 
  tarch::la::Vector<dim, unsigned int> getProcessCoordinates(unsigned int rank, unsigned int topologyOffset) const {
    tarch::la::Vector<dim, unsigned int> processCoordinates(0);
    unsigned int help = rank - topologyOffset;
    for (unsigned int d = 0; d < dim; d++) {
      processCoordinates[d] = help / _divisionFactor4NumberProcesses[d];
      help = help - processCoordinates[d] * _divisionFactor4NumberProcesses[d];
    }
#if (COUPLING_MD_DEBUG == COUPLING_MD_YES)
    std::cout << "Rank=" << rank << " corresponds to process coordinates=" << processCoordinates << std::endl;
#endif
    return processCoordinates;
  }

  unsigned int getRank(tarch::la::Vector<dim, unsigned int> processCoordinates, unsigned int topologyOffset) const {
    unsigned int rank = processCoordinates[0];
    for (unsigned int d = 1; d < dim; d++) {
      rank = rank * _numberProcesses[d] + processCoordinates[d];
    }
    return rank + topologyOffset;
  }
 
private:
  tarch::la::Vector<dim, unsigned int> initDivisionFactor(tarch::la::Vector<dim, unsigned int> numberProcesses) const {
    tarch::la::Vector<dim, unsigned int> div(1);
    for (int d = dim - 2; d > -1; d--) {
      div[d] = div[d + 1] * numberProcesses[d + 1];
    }
    return div;
  }
 
  /* number of processes */
  const tarch::la::Vector<dim, unsigned int> _numberProcesses;
  /* division factor */
  const tarch::la::Vector<dim, unsigned int> _divisionFactor4NumberProcesses;
};
#endif // _MOLECULARDYNAMICS_COUPLING_PARALLELTOPOLOGY_ZYXTOPOLOGY_H_