GeneralBinFinderInZforGeometricSearchDet.h

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#ifndef GeneralBinFinderInZ_H
#define GeneralBinFinderInZ_H

#include "Utilities/BinningTools/interface/BaseBinFinder.h"
#include "TrackingTools/DetLayers/interface/GeometricSearchDet.h"
#include <cmath>

#include<cassert>

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

  GeneralBinFinderInZforGeometricSearchDet() {}

  GeneralBinFinderInZforGeometricSearchDet(
                  std::vector<const GeometricSearchDet*>::const_iterator first,
              std::vector<const GeometricSearchDet*>::const_iterator last) :
    theNbins( last-first -1)  // -1!
  {
    theBins.reserve(theNbins);
    theBorders.reserve(theNbins);
    for (auto i=first; i<last-1; i++) {
      theBins.push_back((**i).position().z());
      theBorders.push_back(((**i).position().z() + 
                (**(i+1)).position().z()) / 2.);
    }
    assert(theNbins==int(theBorders.size()));
    
    theZOffset = theBorders.front(); 
    theZStep = (theBorders.back() - theBorders.front()) / (theNbins-1);
    theInvZStep = 1./theZStep;
  }

  virtual int binIndex( T z) const {
    int bin = int((z-theZOffset)*theInvZStep)+1;
    if (bin<=0) return 0;
    if (bin>=theNbins) return theNbins;

    // check left border
    if ( z < theBorders[bin-1]) {
      // z is to the left of the left border, the correct bin is left
      for (auto i=bin-1; i>0; i--) {  
      if ( z > theBorders[i-1]) return i;
    }
      return 0;
      }
    
    // check right border
    if ( z > theBorders[bin]) {
      // z is to the right of the right border, the correct bin is right
      for (int i=bin+1; i<theNbins; i++) {
    if ( z < theBorders[i]) return i;
      }
      return theNbins;
    }
    // if we arrive here it means that the bin is ok 
    return bin;
  }

  virtual int binIndex( int i) const {
    return std::min( std::max( i, 0), theNbins);
  }
   
  virtual T binPosition( int ind) const {
    return theBins[binIndex(ind)];
  }


private:

  int theNbins=0; // -1
  T theZStep=0;
  T theInvZStep=0;
  T theZOffset=0;
  std::vector<float> theBorders;
  std::vector<T> theBins;
};
#endif