serialization.h

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/*  This file is part of the OpenLB library
 *
 *  Copyright (C) 2023-24 Julius Jeßberger
 *  E-mail contact: info@openlb.net
 *  The most recent release of OpenLB can be downloaded at
 *  <http://www.openlb.net/>
 *
 *  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.
*/
 
 #ifndef SERIALIZATION_H
 #define SERIALIZATION_H
 
#include <cstdlib>
 
#include "controller.h"
#include "geometry/superGeometry.h"
#include "utilities/aliases.h"
#include "utilities/vectorHelpers.h"
 
namespace olb {
 
namespace opti {
 
template<typename S>
class Controller;
 
template<typename S, unsigned dim>
class GeometrySerializer
{
public:
  struct LatticeAndFieldR {
    LatticeR<dim+1> latticeR;
    std::size_t     fieldComponent;
  };
 
  virtual std::size_t getSerializedCellIndex(const int latticeR[]) const = 0;
 
  std::size_t getSerializedCellIndex(LatticeR<dim+1> latticeR) const {
    return getSerializedCellIndex(latticeR.data());
  }
 
  virtual LatticeR<dim+1> getLatticeR(std::size_t index) const = 0;
 
  std::size_t getSerializedComponentIndex(const int latticeR[],
    unsigned iD, unsigned fieldDim) const {
    return fieldDim * getSerializedCellIndex(latticeR) + iD;
  }
 
  std::size_t getSerializedComponentIndex(LatticeR<dim+1> latticeR,
    unsigned iD, unsigned fieldDim) const {
    return fieldDim * getSerializedCellIndex(latticeR) + iD;
  }
 
  std::size_t getSerializedComponentIndex(LatticeAndFieldR coords,
    unsigned fieldDim) const {
    return getSerializedComponentIndex(coords.latticeR, coords.fieldComponent, fieldDim);
  }
 
  LatticeAndFieldR getLatticeAndFieldR(std::size_t index, unsigned fieldDim) const {
    // index = fieldDim * cellIndex + fieldComponent
    const auto fieldCoord = std::div((long int) index, (long int) fieldDim);
    const auto geomCoord = getLatticeR(fieldCoord.quot);
    return {geomCoord, (std::size_t) fieldCoord.rem};
  }
 
  virtual unsigned getNoCells() const = 0;
};
 
template<typename S, unsigned dim>
class SimpleGeometrySerializer : public GeometrySerializer<S,dim>
{
protected:
  CuboidGeometry<S,dim>&          _cGeometry;
  const unsigned                  _noCuboids;
 
private:
  std::vector<unsigned>           _cuboidSizes;   // number of cells per cuboid
  std::vector<unsigned>           _offsets;       // accumulated cuboid sizes
  unsigned                        _noCells;
 
public:
  SimpleGeometrySerializer(CuboidGeometry<S,dim>& cGeometry)
   : _cGeometry(cGeometry),
     _noCuboids(_cGeometry.getNc())
  {
    _cuboidSizes.reserve(_noCuboids);
    _offsets.reserve(_noCuboids);
    for (unsigned i = 0; i < _noCuboids; ++i) {
      _cuboidSizes.push_back(_cGeometry.get(i).getLatticeVolume());
    }
    _offsets.push_back(0);
    for (unsigned i = 1; i < _noCuboids; ++i) {
      _offsets.push_back(_offsets[i-1] + _cuboidSizes[i-1]);
    }
 
    const auto mc = _cGeometry.getMotherCuboid();
    if constexpr (dim == 2) {
      _noCells = (mc.getNx() + 1) * (mc.getNy() + 1);
    } else {
      _noCells = (mc.getNx() + 1) * (mc.getNy() + 1) * (mc.getNz() + 1);
    }
  }
 
  SimpleGeometrySerializer(SuperGeometry<S,dim>& sGeometry)
   : SimpleGeometrySerializer(sGeometry.getCuboidGeometry())
  { }
 
  std::size_t getSerializedCellIndex(const int latticeR[]) const override {
    const Cuboid<S,dim>& c = _cGeometry.get(latticeR[0]);
    const int nX = c.getNx();
    const int nY = c.getNy();
    std::size_t res;
    if constexpr (dim == 2) {
      // cuboid_offset + NX*y + x
      res = _offsets[latticeR[0]] + nX*latticeR[2] + latticeR[1];
    } else {
      // cuboid_offset + NX*NY*z + NX*y + x
      res = _offsets[latticeR[0]] + nX*nY*latticeR[3] + nX*latticeR[2] + latticeR[1];
    }
    return res;
  }
 
  using GeometrySerializer<S,dim>::getSerializedCellIndex;
 
  LatticeR<dim+1> getLatticeR(std::size_t index) const override {
    const auto cuboidIt = std::upper_bound(_offsets.begin(), _offsets.end(), index) - 1;
    LatticeR<dim+1> res;
    res[0] = std::distance(_offsets.begin(), cuboidIt);
 
    const Cuboid<S,dim>& c = _cGeometry.get(res[0]);
    const std::size_t nX = c.getNx();
    if constexpr (dim == 2) {
      // index = cuboid_offset + NX*y + x
      const auto divByNx = std::div((long int) index - *cuboidIt, (long int) nX);
      res[2] = divByNx.quot;
      res[1] = divByNx.rem;
    } else {
      // index = cuboid_offset + NX*NY*z + NX*y + x
      const std::size_t nY = c.getNy();
      const auto divByNxNy = std::div((long int) index - *cuboidIt, (long int) nX*nY);
      res[3] = divByNxNy.quot;
      const auto divByNx = std::div(divByNxNy.rem, (long int) nX);
      res[2] = divByNx.quot;
      res[1] = divByNx.rem;
    }
    return res;
  }
 
  unsigned getNoCells() const override {
    return _noCells;
  }
};
 
 
template<typename S, unsigned dim>
class SparseGeometrySerializer : public GeometrySerializer<S,dim>
{
private:
  using L = LatticeR<dim+1>;
  std::vector<L>                             _coords;
  mutable FunctorPtr<SuperIndicatorF<S,dim>> _indicator;  // indicates which cells are serialized
      // the _indicator should never be changed, otherwise this class loses its
      // correctness. The "mutable" keyword is only necessary because FunctorPtr
      // does not support const arithmetic and should be removed if possible.
 
public:
  SparseGeometrySerializer(SuperGeometry<S,dim>& superGeometry,
    FunctorPtr<SuperIndicatorF<S,dim>>&& indicator)
   : _indicator(std::move(indicator))
  {
    const auto cGeometry = superGeometry.getCuboidGeometry();
    L latticeR;
    for (unsigned iC = 0; iC < cGeometry.getNc(); ++iC) {
      latticeR[0] = iC;
      const int nX = cGeometry.get(iC).getNx();
      const int nY = cGeometry.get(iC).getNy();
      for (int iX=0; iX<nX; iX++) {
        latticeR[1] = iX;
        for (int iY=0; iY<nY; iY++) {
          latticeR[2] = iY;
          if constexpr (dim == 2) {
            if (_indicator(latticeR.data())) {
              _coords.push_back(latticeR);
            }
          } else {
            const int nZ = cGeometry.get(iC).getNz();
            for (int iZ=0; iZ<nZ; iZ++) {
              latticeR[3] = iZ;
 
              if (_indicator(latticeR.data())) {
                _coords.push_back(latticeR);
              }
            }
          }
        }
      }
    }
  }
 
  SparseGeometrySerializer(SuperGeometry<S,dim>& superGeometry,
    FunctorPtr<IndicatorF<S,dim>>&& indicator)
   : SparseGeometrySerializer(superGeometry,
     new SuperIndicatorFfromIndicatorF<S,dim>(std::move(indicator), superGeometry))
  { }
 
  std::size_t getSerializedCellIndex(const int latticeR[]) const override {
#ifdef OLB_DEBUG
    // check if cell lies in indicated domain
    bool isInside;
    _indicator(&isInside, latticeR);
    if (! isInside) {
      OstreamManager clout (std::cout, "SparseGeometrySerializer");
      clout << "Warning: the passed cell does not lie in the indicated domain "
        << "and can therefore not be accessed." << std::endl;
      std::exit(1);
    }
#endif
    const L point (latticeR);
    const auto upper = std::upper_bound(
      _coords.begin(), _coords.end(), point, [](const L& a, const L& b){
      return lex_smaller(a, b);
    });
    return std::distance(_coords.begin(), upper - 1);
  }
 
  using GeometrySerializer<S,dim>::getSerializedCellIndex;
 
  LatticeR<dim+1> getLatticeR(std::size_t index) const override {
#ifdef OLB_DEBUG
    // check if index lies in accessible range
    if (index >= _coords.size()) {
      OstreamManager clout (std::cout, "SparseGeometrySerializer");
      clout << "Warning: the passed index is higher than the number of cells "
        << "which are marked by indicator." << std::endl;
      std::exit(1);
    }
#endif
    return _coords[index];
  }
 
  unsigned getNoCells() const override {
    return _coords.size();
  }
};
 
template<typename S, unsigned dim>
int getMaterialGlobally (SuperGeometry<S,dim>& sGeometry, LatticeR<dim+1> latticeR)
{
  int material = 0;
  if ( sGeometry.getLoadBalancer().rank(latticeR[0]) == singleton::mpi().getRank() ) {
    material = sGeometry.get(latticeR);
  }
#ifdef PARALLEL_MODE_MPI
  singleton::mpi().bCast(&material, 1, sGeometry.getLoadBalancer().rank(latticeR[0]));
#endif
  return material;
}
 
 
template <typename T, typename DESCRIPTOR>
class BlockLatticeSerialDataF : public BlockLatticeF<T,DESCRIPTOR> {
protected:
  static constexpr unsigned d = DESCRIPTOR::d;
  Controller<T>&                    _controller;
  const GeometrySerializer<T,d>&    _serializer;
  const int                         _iC;
  std::function<T(T)>               _projection;
public:
  BlockLatticeSerialDataF(BlockLattice<T,DESCRIPTOR>& blockLattice,
    Controller<T>& controller, const GeometrySerializer<T,d>& serializer,
    int iC, unsigned dataDim, std::function<T(T)> projection)
  : BlockLatticeF<T,DESCRIPTOR>(blockLattice, dataDim),
    _controller(controller), _serializer(serializer), _iC(iC),
    _projection(projection)
  {
    this->getName() = "BlockLatticeSerialDataF";
  }
 
  bool operator() (T output[], const int input[])
  {
    if (this->getBlock().isInsideCore(input)) {
      int latticeR[4] = {_iC, input[0], input[1], 0};
      if constexpr (d == 3) {
        latticeR[3] = input[2];
      }
      const auto index = _serializer.getSerializedComponentIndex(latticeR, 0, this->getTargetDim());
      for (int i = 0; i < this->getTargetDim(); ++i) {  // todo: benutze std::copy_n?
        output[i] = _projection(_controller.getControl(index + i));
      }
      return true;
    }
    return false;
  }
};
 
 
// Controller stores field values, which are (component-wise, point by point)
// transformed by the projection function and then returned.
// The controller is global, it is expected to have data for the entire domain.
// Hence, every process must have access to the ''same'' controller.
template <typename T, typename DESCRIPTOR>
class SuperLatticeSerialDataF : public SuperLatticeF<T,DESCRIPTOR> {
protected:
  std::shared_ptr<const GeometrySerializer<T,DESCRIPTOR::d>> _serializer;
public:
  SuperLatticeSerialDataF(SuperLattice<T,DESCRIPTOR>& superLattice,
    Controller<T>& controller, unsigned dataDim,
    std::shared_ptr<const GeometrySerializer<T,DESCRIPTOR::d>> serializer,
    std::function<T(T)> projection = [](T x){ return x; })
  : SuperLatticeF<T,DESCRIPTOR>(superLattice, dataDim),
    _serializer(serializer)
  {
    this->getName() = "SuperLatticeSerialDataF";
 
    const int maxC = superLattice.getLoadBalancer().size();
    this->_blockF.reserve(maxC);
 
    for (int iC = 0; iC < maxC; ++iC) {
      this->_blockF.emplace_back(
        new BlockLatticeSerialDataF<T,DESCRIPTOR>(
          superLattice.getBlock(iC),
          controller,
          *_serializer,
          superLattice.getLoadBalancer().glob(iC),
          dataDim,
          projection)
      );
    }
  }
 
  SuperLatticeSerialDataF(SuperLattice<T,DESCRIPTOR>& superLattice,
    Controller<T>& controller, unsigned dataDim,
    std::function<T(T)> projection = [](T x){ return x; })
  : SuperLatticeSerialDataF(superLattice, controller, dataDim,
      std::make_shared<const SimpleGeometrySerializer<T,DESCRIPTOR::d>>(superLattice),
      projection)
  { }
};
 
 
 
}
}
#endif