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//
//
// $Id$
//
//
// Class G4SimpleLocator 
//
// class description:
// 
// Implementing the calculation of the intersection point with a boundary when
// PropagationInField is used. Derived from method LocateIntersectionPoint()
// from G4PropagatorInField, it is based on a linear method for finding the
// intersection point; the difference compared to G4MultiLevelLocator is that
// no 'depth' algorithm is used in case of slow progress for finding the
// intersection point.

// History:
// -------
// 27.10.08 - Tatiana Nikitina: Derived from LocateIntersectionPoint() from 
//                              G4PropagatorInField class
// ---------------------------------------------------------------------------

#ifndef G4SIMPLELOCATOR_HH
#define G4SIMPLELOCATOR_HH

#include "G4VIntersectionLocator.hh"

class G4SimpleLocator : public G4VIntersectionLocator
{
   public:  // with description 
 
     G4SimpleLocator(G4Navigator *theNavigator);
        // Constructor
     ~G4SimpleLocator();
        // Default destructor

     G4bool EstimateIntersectionPoint( 
         const  G4FieldTrack&       curveStartPointTangent,  // A
         const  G4FieldTrack&       curveEndPointTangent,    // B
         const  G4ThreeVector&      trialPoint,              // E
                G4FieldTrack&       intersectPointTangent,   // Output
	        G4bool&             recalculatedEndPoint,    // Out
                G4double&           fPreviousSafety,         // In/Out
                G4ThreeVector&      fPreviousSftOrigin);     // In/Out
      // If such an intersection exists, this function calculates the
      // intersection point of the true path of the particle with the surface
      // of the current volume (or of one of its daughters). 
      // Should use lateral displacement as measure of convergence
};

#endif