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// G4WeightWindowStore
//
// Class description:
//
// Implementation of a weight window store according to the
// G4VWeightWindowStore interface.
// See also G4VWeightWindowStore.

// Author: Michael Dressel (CERN), 2003
// Modified: Alex Howard (CERN), 2013 - Changed class to a 'singleton'
// ----------------------------------------------------------------------
#ifndef G4WEIGHTWINDOWSTORE_HH
#define G4WEIGHTWINDOWSTORE_HH 1

#include "G4VWeightWindowStore.hh"
#include "G4GeometryCellWeight.hh"
#include <set>
#include <vector>

class G4WeightWindowStore: public G4VWeightWindowStore
{
  public:  // with description

    static G4WeightWindowStore* GetInstance();
      // return ptr to singleton instance of the class

    static G4WeightWindowStore* GetInstance(const G4String& ParallelWorldName);
      // return ptr to singleton instance of the class

    virtual G4double GetLowerWeight(const G4GeometryCell& gCell, 
                                          G4double partEnergy) const;
      // derive a lower weight bound value of a "cell" addressed by a 
      // G4GeometryCell and the corresponding energy from the store

    virtual G4bool IsKnown(const G4GeometryCell &gCell) const;
      // returns true if the gCell is in the store, else false 

    void Clear();

    void SetWorldVolume();
      // set a pointer to the world volume of the weightwindow geometry
    void SetParallelWorldVolume(const G4String& paraName);
      // set a pointer to parallel world volume of the weightwindow geometry

    virtual const G4VPhysicalVolume& GetWorldVolume() const;
      // return a reference to the world volume of the weightwindow geometry
    virtual const G4VPhysicalVolume* GetParallelWorldVolumePointer() const;
      // return a pointer to parallel world volume of the weightwindow geometry

    void AddLowerWeights(const G4GeometryCell& gCell,
                         const std::vector<G4double>& lowerWeights);
      // add lower weights. Only if general upper energy bounds have been set

    void AddUpperEboundLowerWeightPairs(const G4GeometryCell& gCell,
                                  const G4UpperEnergyToLowerWeightMap& enWeMap);
      // set upper energy - lower weight pairs for a cell

    void SetGeneralUpperEnergyBounds(const std::set<G4double,
                                          std::less<G4double> >& enBounds);
  protected:

    explicit G4WeightWindowStore();
      // initialise the weight window store for the given geometry
    explicit G4WeightWindowStore(const G4String& ParallelWorldName);
      // initialise the weight window store for the given geometry

   ~G4WeightWindowStore();
      // destructor

  private:

    G4bool IsInWorld(const G4VPhysicalVolume&) const;
    void Error(const G4String& m) const;
    void SetInternalIterator(const G4GeometryCell& gCell) const;

  private:

    const G4VPhysicalVolume* fWorldVolume = nullptr;  

    std::set<G4double, std::less<G4double> > fGeneralUpperEnergyBounds;
    G4GeometryCellWeight fCellToUpEnBoundLoWePairsMap;
    mutable G4GeometryCellWeight::const_iterator fCurrentIterator;

    static G4ThreadLocal G4WeightWindowStore* fInstance;
};

#endif