G4SimpleHeum.hh

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// G4SimpleHeum
//
// Class description:
//
// Simple Heum stepper for magnetic field:
//        x_1 = x_0  +
//              h * 1/4 * dx(t0,x0)  +
//                  3/4 * dx(t0+2/3*h, x0+2/3*h*(dx(t0+h/3,x0+h/3*dx(t0,x0)))) 
//
// Third order solver.

// Created: W.Wander <wwc@mit.edu>, 12/09/1997
// -------------------------------------------------------------------
#ifndef G4SIMPLEHEUM_HH
#define G4SIMPLEHEUM_HH

#include "G4MagErrorStepper.hh"

class G4SimpleHeum : public G4MagErrorStepper
{

  public:  // with description

    G4SimpleHeum(G4EquationOfMotion* EqRhs, G4int num_variables = 6);
   ~G4SimpleHeum();
      // Constructor and destructor.

    void DumbStepper( const G4double y[],
                      const G4double dydx[],
                            G4double h,
                            G4double yout[] );

  public:  // without description
  
    inline G4int IntegratorOrder() const { return 3; }

  private:

    G4int fNumberOfVariables = 0;

    G4double* dydxTemp = nullptr;
    G4double* dydxTemp2 = nullptr;
    G4double* yTemp = nullptr;
    G4double* yTemp2 = nullptr;
      // scratch space    
};

#endif