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// $Id: G4MultiLevelLocator.hh,v 1.2 2008/10/29 14:31:55 gcosmo Exp $
// GEANT4 tag $Name: geant4-09-03 $
//
//
// Class G4MultiLevelLocator 
//
// 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 by means of a 'depth' algorithm in case of slow progress
// (intersection is not found after 100 trials).

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

#ifndef G4MULTILEVELLOCATOR_HH
#define G4MULTILEVELLOCATOR_HH

#include "G4VIntersectionLocator.hh"

class G4MultiLevelLocator : public G4VIntersectionLocator
{
   public:  // with description 
 
     G4MultiLevelLocator(G4Navigator *theNavigator);
        // Constructor
     ~G4MultiLevelLocator();
        // 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

   private:

     static const G4int max_depth=4;

     G4FieldTrack* ptrInterMedFT[max_depth+1];
       // Used to store intermediate tracks values in case of too slow progress

     G4int maxNumberOfStepsForIntersection;
     G4int maxNumberOfCallsToReIntegration;
     G4int maxNumberOfCallsToReIntegration_depth;
       //  Counters for Statistics about Location and ReIntegrations
};

#endif