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//
// $Id: F01FieldSetup.hh,v 1.2 2003/12/01 15:47:52 japost Exp $
// GEANT4 tag $Name: geant4-06-00-patch-01 $
//
//
//    A class for control of the Magnetic Field of the detector.
//  The field is assumed to be uniform.
// 
//  $ Id:  $

// Should this be a:
//    i) messenger
//   ii) user class that creates the field       ? 
//  iii) simply a derived class of Uniform field ?  <== I have chosen this now.
//   iv) a field manager that creates/updates field    (Prefered?)
//


#ifndef F01FieldSetup_H
#define F01FieldSetup_H

#include "G4MagneticField.hh"
#include "G4UniformMagField.hh"

class G4FieldManager;
class G4ChordFinder;
class G4Mag_UsualEqRhs;
class G4MagIntegratorStepper;
class F01FieldMessenger;

class F01FieldSetup
{
public:
  F01FieldSetup(G4ThreeVector) ;  //  The value of the field
  F01FieldSetup() ;               //  A zero field

 ~F01FieldSetup() ;  
      
  
  void SetStepperType( G4int i) { fStepperType = i ; }

  void SetStepper();

  void SetMinStep(G4double s) { fMinStep = s ; }

  void InitialiseAll();    //  Set parameters and call method below
  void CreateStepperAndChordFinder();

  void SetFieldValue(G4ThreeVector fieldVector) ;
  void SetFieldValue(G4double      fieldValue) ;
  G4ThreeVector GetConstantFieldValue();

protected:

      // Find the global Field Manager

  G4FieldManager*         GetGlobalFieldManager() ;   // static 

  G4FieldManager*         fFieldManager ;
  G4ChordFinder*          fChordFinder ;
  G4Mag_UsualEqRhs*       fEquation ; 
  G4MagneticField*        fMagneticField ; 

  G4MagIntegratorStepper* fStepper ;
  G4int                   fStepperType ;

  G4double                fMinStep ;
 
  F01FieldMessenger*      fFieldMessenger;

};

#endif