G4IStepper.h

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//--------------------------------------------------------------
//
// G4IStepper.h
//
//--------------------------------------------------------------
#ifndef G4ISTEPPER_H
#define G4ISTEPPER_H
#ifndef CASSERT
#include <cassert>
#define CASSERT
#endif
#ifndef G4IBFIELD_H
#include "G4I/G4IBField.h"
#endif

class BField;
class G4Mag_UsualEqRhs;
class G4ClassicalRK4;
class G4MagInt_Driver;

//======================================================================
#ifdef SITE_HAS_GEANT4
class G4IStepper {
public:
  G4IStepper(BField* magField);
  G4IStepper(BField* magField, double stepMin, double errStep);
  ~G4IStepper();
  
  bool StepOnce(const double* xStart,
                const double* vDir,
                double momentum,
                double mass,
                double charge,
                double stepSize,
                double* xNext,
                double* vDirNext,
                double* pNext);

private:
  double            fStepMin;     // Minimum step size (Geant4 internal units)
  double            fErrStep;     // Step size error
  G4IBField         fMagField;    // The magnetic field to use
  G4Mag_UsualEqRhs* fRhs;         // The right hand side of the eqn. of motion
  G4ClassicalRK4*   fStepper;     // The stepper class
  G4MagInt_Driver*  fDriver;      // The G4 integration driver
  double            fCurveLength; //...
};

//======================================================================
#else  // SITE_HAS_GEANT4
class G4IStepper {
public:
  G4IStepper(BField* magField) { }
  G4IStepper(BField* magField, double stepMin, double errStep) { }
  ~G4IStepper() { }
  
  bool StepOnce(const double* xStart,
                const double* vDir,
                double momentum,
                double mass,
                double charge,
                double stepSize,
                double* xNext,
                double* vDirNext,
                double* pNext) { 
    assert("G4IStepper: Program compiled without GEANT4 support.\n"=0);
  }
};
#endif // SITE_HAS_GEANT4
#endif // G4ISTEPPER_H

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