VerletListsCells.h

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#pragma once
 
#include "autopas/containers/LoadEstimators.h"
#include "autopas/containers/cellTraversals/BalancedTraversal.h"
#include "autopas/containers/verletListsCellBased/VerletListsLinkedBase.h"
#include "autopas/containers/verletListsCellBased/verletListsCells/VerletListsCellsHelpers.h"
#include "autopas/containers/verletListsCellBased/verletListsCells/neighborLists/VLCCellPairNeighborList.h"
#include "autopas/containers/verletListsCellBased/verletListsCells/traversals/VLCTraversalInterface.h"
#include "autopas/options/DataLayoutOption.h"
#include "autopas/options/LoadEstimatorOption.h"
 
namespace autopas {
 
template <class Particle_T, class NeighborList>
class VerletListsCells : public VerletListsLinkedBase<Particle_T> {
 public:
  VerletListsCells(const std::array<double, 3> &boxMin, const std::array<double, 3> &boxMax, const double cutoff,
                   const double skin = 0, const double cellSizeFactor = 1.0,
                   const LoadEstimatorOption loadEstimator = LoadEstimatorOption::squaredParticlesPerCell,
                   typename VerletListsCellsHelpers::VLCBuildType dataLayoutDuringListRebuild =
                       VerletListsCellsHelpers::VLCBuildType::soaBuild)
      : VerletListsLinkedBase<Particle_T>(boxMin, boxMax, cutoff, skin, cellSizeFactor),
        _loadEstimator(loadEstimator),
        _dataLayoutDuringListRebuild(dataLayoutDuringListRebuild) {}
 
  [[nodiscard]] ContainerOption getContainerType() const override { return _neighborList.getContainerType(); }
 
  BalancedTraversal::EstimatorFunction getLoadEstimatorFunction() {
    // (Explicit) static cast required for Apple Clang (last tested version: 17.0.0)
    switch (static_cast<LoadEstimatorOption::Value>(this->_loadEstimator)) {
      case LoadEstimatorOption::squaredParticlesPerCell: {
        return [&](const std::array<unsigned long, 3> &cellsPerDimension,
                   const std::array<unsigned long, 3> &lowerCorner, const std::array<unsigned long, 3> &upperCorner) {
          return loadEstimators::squaredParticlesPerCell((this->_linkedCells).getCells(), cellsPerDimension,
                                                         lowerCorner, upperCorner);
        };
      }
      case LoadEstimatorOption::neighborListLength: {
        return [&](const std::array<unsigned long, 3> &cellsPerDimension,
                   const std::array<unsigned long, 3> &lowerCorner, const std::array<unsigned long, 3> &upperCorner) {
          return loadEstimators::neighborListLength<Particle_T, NeighborList>(_neighborList, cellsPerDimension,
                                                                              lowerCorner, upperCorner);
        };
      }
 
      case LoadEstimatorOption::none:
        [[fallthrough]];
      default: {
        return
            [&](const std::array<unsigned long, 3> &cellsPerDimension, const std::array<unsigned long, 3> &lowerCorner,
                const std::array<unsigned long, 3> &upperCorner) { return 1; };
      }
    }
  }
 
  void computeInteractions(TraversalInterface *traversal) override {
    // Check if traversal is allowed for this container and give it the data it needs.
    _neighborList.setUpTraversal(traversal);
    if (auto *balancedTraversal = dynamic_cast<BalancedTraversal *>(traversal)) {
      balancedTraversal->setLoadEstimator(getLoadEstimatorFunction());
    }
 
    traversal->initTraversal();
    traversal->traverseParticles();
    traversal->endTraversal();
  }
 
  size_t getNumberOfPartners(const Particle_T *particle) const { return _neighborList.getNumberOfPartners(particle); }
 
  void rebuildNeighborLists(TraversalInterface *traversal) override {
    this->_verletBuiltNewton3 = traversal->getUseNewton3();
 
    _neighborList.buildAoSNeighborList(traversal->getTraversalType(), this->_linkedCells, this->_verletBuiltNewton3);
 
    if (traversal->getDataLayout() == DataLayoutOption::soa) {
      _neighborList.generateSoAFromAoS(this->_linkedCells);
    }
 
    // the neighbor list is now valid
    this->_neighborListIsValid.store(true, std::memory_order_relaxed);
  }
 
  [[nodiscard]] const std::array<double, 3> &getCellLength() const {
    return this->_linkedCells.getCellBlock().getCellLength();
  }
 
 private:
  NeighborList _neighborList;
 
  LoadEstimatorOption _loadEstimator;
 
  typename VerletListsCellsHelpers::VLCBuildType _dataLayoutDuringListRebuild;
};
}  // namespace autopas