MpdRoot_KFParticle/mpdfield/MpdFieldMap.h

// -------------------------------------------------------------------------
//                            MpdFieldMap header file                  -----
//        Created 23/07/13  by P. Batyuk (MPD) <batyuk@jinr.ru>        -----
//                          from MpdFieldMap (PNDROOT)                 -----
// -------------------------------------------------------------------------

#ifndef PNDFIELDMAP_H
#define PNDFIELDMAP_H 1

#include "FairField.h"

class TArrayF;
class MpdFieldMapData;
class MpdFieldPar;

class MpdFieldMap : public FairField {
  
 public:
  
  /** Default constructor **/
  MpdFieldMap();
  
  /** Standard constructor
   ** @param name       Name of field map
   ** @param fileType   R = ROOT file, A = ASCII
   **/
  MpdFieldMap(const char* mapName, const char* fileType = "R");
  
  /** Constructor from MpdFieldPar **/
  MpdFieldMap(MpdFieldPar* fieldPar);

  /** Destructor **/
  virtual ~MpdFieldMap();
  
  /** Initialisation (read map from file) **/
  virtual void Init();
  
  /** Get the field components at a certain point 
   ** @param x,y,z     Point coordinates (global) [cm]
   ** @value Bx,By,Bz  Field components [kG]
   **/
  virtual Double_t GetBx(Double_t x, Double_t y, Double_t z);
  virtual Double_t GetBy(Double_t x, Double_t y, Double_t z);
  virtual Double_t GetBz(Double_t x, Double_t y, Double_t z);

  virtual void GetFieldValue(const Double_t point[3], Double_t* bField);
  
  virtual void GetBxyz(const Double_t point[3], Double_t* bField);
  
  /** Determine whether a point is inside the field map   **/
  virtual bool IsInside(double x, double y, double z);
  
  /** Write the field map to an ASCII file **/
  void WriteAsciiFile(const char* fileName);
  
  /** Write field map data to a ROOT file **/
  void WriteRootFile(const char* fileName, const char* mapName);
  
  /** Set the position of the field centre **/
  void SetPosition(Double_t x, Double_t y, Double_t z);
  
  /** Set a global field scaling factor **/
  void SetScale(Double_t factor) { fScale = factor; }

  /** Accessors to field parameters in local coordinate system **/
  Double_t GetXmin()  const { return fXmin; } 
  Double_t GetYmin()  const { return fYmin; }
  Double_t GetZmin()  const { return fZmin; }
  Double_t GetXmax()  const { return fXmax; }  
  Double_t GetYmax()  const { return fYmax; }
  Double_t GetZmax()  const { return fZmax; }
  Double_t GetXstep() const { return fXstep; }  
  Double_t GetYstep() const { return fYstep; }
  Double_t GetZstep() const { return fZstep; }
  Int_t    GetNx()    const { return fNx; }
  Int_t    GetNy()    const { return fNy; }
  Int_t    GetNz()    const { return fNz; }

  Double_t GetUnit()  const {return funit; }

  /** Accessor to field centre position in global system **/
  Double_t GetPositionX() const { return fPosX; }
  Double_t GetPositionY() const { return fPosY; }
  Double_t GetPositionZ() const { return fPosZ; }
  
  /** Accessor to global scaling factor  **/
  Double_t GetScale() const { return fScale; }

  /** Accessors to the field value arrays **/
  TArrayF* GetBx() const { return fBx; }
  TArrayF* GetBy() const { return fBy; }
  TArrayF* GetBz() const { return fBz; }
  
  /** Accessor to field map file **/
  const char* GetFileName() { return fFileName.Data(); }
  
  /** Screen output **/
  virtual void Print();
  
 protected:
  
  /** Reset the field parameters and data **/
  void Reset();
  
  /** Read the field map from an ASCII file **/
  void ReadAsciiFile(const char* fileName);
  
  /** Read field map from a ROOT file **/	
  void ReadRootFile(const char* fileName, const char* mapName);
  
  /** Set field parameters and data **/
  void SetField(const MpdFieldMapData* data);
  
  /** Get field values by interpolation of the grid.
   ** @param dx,dy,dz  Relative distance from grid point [cell units]
   **/
  Double_t Interpolate(Double_t dx, Double_t dy, Double_t dz); 
  
  /// Calculate Phi-angle in the Polar Reference Frame
  Double_t MPDCalcPhi(Double_t x, Double_t y); 

  /// Interpolation of Br-component of the magnetic field
  Double_t MPDCalcBr(Double_t x, Double_t y);
  
  /// Interpolation of Bz-component of the magnetic field
  Double_t MPDCalcBz(Double_t x, Double_t y);  

  ///

  /** Map file name **/
  TString fFileName;

  /** Global scaling factor (w.r.t. map on file) **/
  Double_t fScale;             

  /** Units used in map file**/
  Double_t funit;             

  /** Field centre position in global coordinates  **/
  Double_t fPosX, fPosY, fPosZ; 

  /** Field limits in local coordinate system **/
  Double_t fXmin, fXmax, fXstep;
  Double_t fYmin, fYmax, fYstep;
  Double_t fZmin, fZmax, fZstep;


  /** Number of grid points  **/
  Int_t fNx, fNy, fNz;

  /** Arrays with the field values  **/
  TArrayF* fBx;
  TArrayF* fBy;
  TArrayF* fBz;


  /** Variables for temporary storage 
   ** Used in the very frequently called method GetFieldValue  **/
  Double_t fHa[2][2][2];            //! Field at corners of a grid cell
  Double_t fHb[2][2];               //! Interpolated field (2-dim)
  Double_t fHc[2];                  //! Interpolated field (1-dim)
    
ClassDef(MpdFieldMap,1) 

};

#endif