PeriodicBinFinderInPhi.h

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#ifndef PeriodicBinFinderInPhi_H
#define PeriodicBinFinderInPhi_H

#include "Utilities/BinningTools/interface/BaseBinFinder.h"

#include <cmath>

template <class T>
class PeriodicBinFinderInPhi final : public BaseBinFinder<T> {
public:

  PeriodicBinFinderInPhi()  {}

  PeriodicBinFinderInPhi( T firstPhi, int nbins) :
    theNbins( nbins), thePhiStep( twoPiC / T(nbins)), theInvPhiStep(T(1)/thePhiStep),
    thePhiOffset( firstPhi - T(0.5)*thePhiStep) {}

  virtual int binIndex( T phi) const {
    T tmp = std::fmod((phi - thePhiOffset), twoPiC)*theInvPhiStep;
    if ( tmp < 0) tmp += theNbins;
    return std::min( int(tmp), theNbins-1);
  }

  virtual int binIndex( int i) const {
    int ind = i % theNbins;
    return ind < 0 ? ind+theNbins : ind;
  }
   
  virtual T binPosition( int ind) const {
    return thePhiOffset + thePhiStep * ( T(ind) + T(0.5));
  }

  static constexpr T pi() { return piC;}
  static constexpr T twoPi() { return twoPiC;}

private:

  static constexpr T piC = 3.141592653589793238;
  static constexpr T twoPiC = 2*piC;



  int theNbins=0;
  T thePhiStep=0;
  T theInvPhiStep=0;
  T thePhiOffset=0;

};
#endif