Helper.h

#ifndef Helper_HH
#define Helper_HH

#include "StEventTypes.h"
#include "StPhysicalHelixD.hh"
//#include "StThreeVectorD.hh"
//#include "StThreeVectorF.hh"


double distance(double a1, double b1, double a2, double b2);
double distance(const StThreeVectorF& point1,
                const StThreeVectorF& point2);

double dca3d(const StPhysicalHelixD&, const StThreeVectorF& point);

double dca2d(const StPhysicalHelixD&, const StThreeVectorF& point,
             const StThreeVectorF* origin=0);

double dcaz(const StPhysicalHelixD&, const StThreeVectorF& point);

double crossingAngle(const StPhysicalHelixD& helix,
                     const StTpcHit* hit, float bField=0);

double padrowDca(const StPhysicalHelixD& helix,
                 const StTpcHit* hit);

// helix stuff
//
double propagateToPadrow(const StPhysicalHelixD& helix,
                         const StTpcHit* hit);
double helixPadrowDca(const StPhysicalHelixD& helix,
                      const StTpcHit* hit);
double helixCrossingAngle(const StPhysicalHelixD& helix, 
                     const StTpcHit* hit, float bField);

double helixCrossingAngle(float pt, float phi, int sector);

double helixDca2D(const StPhysicalHelixD&,const StThreeVectorF& point);


// straight line residual stuff
//
StThreeVectorF lineAt2d(const StPhysicalHelixD&, const StThreeVectorF& point);

double 
linePadrowDca(const StPhysicalHelixD& helix,
              const StTpcHit* hit);

double
lineCrossingAngle(const StPhysicalHelixD& helix,
                  const StTpcHit* hit);

double
lineCrossingAngle(const StPhysicalHelixD& helix,
                  const int sector);

double
lineDca2D(const StPhysicalHelixD& helix,
          const StThreeVectorF& hit,
          const StThreeVectorF& origin);

#endif