ITS/AliITSTPArrayFit.h

   1 /* Copyright(c) 2009-2011, ALICE Experiment at CERN, All rights reserved. *
   2  * See cxx source for full Copyright notice                               */
   3
   4 /* $Id$ */
   5
   6
   7 #ifndef ALIITSTPARRAYFIT_H
   8 #define ALIITSTPARRAYFIT_H
   9
  10 ///////////////////////////////////////////////////////////////////////////////////////////////
  11 //                                                                                           //
  12 // The line is defined by equations (1)                                                      //
  13 // a0*z+a1*x-a0*a1=0 and                                                                     //
  14 // b0*z+b1*y-b0*b1=0                                                                         //
  15 // where x,y,z are NOT the lab axes but z is the lab axis along which the track              //
  16 // has the largest lever arm and x,y are the remaining 2 axis in                             //
  17 // the order of fgkAxisID[z][0], fgkAxisID[z][1]                                             //
  18 // The parameters are fParams[kA0,kB0,kA1,kB1] and the axis chosen as the independent        //
  19 // var. is fParAxis (i.e. if fParAxis==kZ, then a0=ax,b0=bx, a1=ay,b1=by)                    //
  20 //                                                                                           //
  21 //                                                                                           //
  22 // The helix is defined by the equations (2)                                                 //
  23 // X(t) = (dr+R)*cos(phi0) - (R+sum{dRi})*cos(t+phi0) + sum{dRi*cos(phi0+ti)}                //
  24 // Y(t) = (dr+R)*sin(phi0) - (R+sum{dRi})*sin(t+phi0) + sum{dRi*sin(phi0+ti)}                //
  25 // Z(t) = dz - (R+sum{dRi})*t*tg(dip) + sum{dRi*ti}*tg(dip)                                  //
  26 // where dRi is the change of the radius due to the ELoss at parameter ti                    //
  27 //                                                                                           //
  28 // Author: ruben.shahoyan@cern.ch                                                            //
  29 //                                                                                           //
  30 ///////////////////////////////////////////////////////////////////////////////////////////////
  31
  32
  33 #include <TObject.h>
  34 #include <TMath.h>
  35 #include "AliTrackPointArray.h"
  36 class AliSymMatrix;
  37 class AliLog;
  38 class AliParamSolver;
  39
  40
  41 class AliITSTPArrayFit : public TObject
  42 {
  43  public:
  44   enum {kFitDoneBit=BIT(14),kCovInvBit=BIT(15),
  45         kCosmicsBit=BIT(16),kELossBit=BIT(17),
  46         kIgnoreCovBit=BIT(18),
  47         kMask=BIT(24)-1};
  48   enum {kXX=0,kXY=1,kXZ=2,kYX=kXY,kYY=3,kYZ=4,kZX=kXZ,kZY=kYZ,kZZ=5};
  49   enum {kA0,kB0,kA1,kB1};                // line params
  50   enum {kD0,kPhi0,kR0,kDZ,kDip};         // helix params
  51   enum {kX,kY,kZ};
  52   enum {kMaxParam=6,kMaxParamSq = kMaxParam*(kMaxParam+1)/2};
  53   enum {kLrBeamPime, kLrSPD1,kLrSPD2, kLrShield1, kLrSDD1,kLrSDD2, kLrShield2, kLrSSD1,kLrSSD2,kMaxLrITS};
  54   //
  55  public:
  56   AliITSTPArrayFit();
  57   AliITSTPArrayFit(Int_t npoints);
  58   AliITSTPArrayFit(const AliITSTPArrayFit &fit);
  59   AliITSTPArrayFit& operator= (const AliITSTPArrayFit& src);
  60   virtual ~AliITSTPArrayFit();
  61   //
  62   void          AttachPoints(const AliTrackPointArray* points, Int_t pfirst=-1,Int_t plast=-1);
  63   Bool_t        SetFirstLast(Int_t pfirst=-1,Int_t plast=-1);
  64   AliTrackPointArray* GetPoints()                           const {return (AliTrackPointArray*)fPoints;}
  65   //
  66   void          SetBz(Double_t bz)                                {fBz = bz;}
  67   Double_t      GetBz()                                     const {return fBz;}
  68   Bool_t        IsFieldON()                                 const {return TMath::Abs(fBz)>1e-5;}
  69   Bool_t        IsTypeCosmics()                             const {return TestBit(kCosmicsBit);}
  70   Bool_t        IsTypeCollision()                           const {return !IsTypeCosmics();}
  71   Int_t         GetCharge()                                 const {return fCharge;}
  72   Int_t         GetSignQB()                                 const {return fBz<0 ? -fCharge:fCharge;}
  73   void          GetResiduals(Double_t *res, Int_t ipnt)     const;
  74   void          GetResiduals(Double_t *resPCA, const Double_t* xyz, const Double_t* covI=0)  const;
  75   Double_t      GetPosition( Double_t *xyzPCA, const Double_t* xyz, const Double_t* covI=0)  const;
  76   Double_t      GetPosition( Double_t *xyzPCA, const AliTrackPoint *pntCovInv)               const;
  77   void          GetResiduals(Double_t *xyzPCA, const AliTrackPoint *pntCovInv)               const;
  78   void          GetPosition(Double_t *xyz, Double_t t)      const;
  79   void          GetPosition(Double_t *xyz, Int_t pnt)       const;
  80   void          GetDirCos(Double_t *dircos, Double_t t)     const;
  81   Double_t      GetPCA2PlaneInfo(Double_t *xyz, Double_t *dir=0, Int_t axis=kY, Double_t axval=0) const;
  82   Double_t      CalcChi2NDF()                               const;
  83   Double_t      GetChi2NDF()                                const {return fChi2NDF;}
  84   Double_t      GetParPCA(const double *xyz, const double *covI=0)        const;
  85   //
  86   void          GetDResDParamsLine (Double_t *dXYZdP, const Double_t *xyz, const Double_t *covI=0) const;
  87   void          GetDResDParamsLine (Double_t *dXYZdP, Int_t ipnt) const;
  88   void          GetDResDParams(Double_t *dXYZdP, const Double_t *xyz, const Double_t *covI=0);
  89   void          GetDResDParams(Double_t *dXYZdP, Int_t ipnt);
  90   //
  91   void          GetDResDPosLine (Double_t *dXYZdP,/*const Double_t *xyz,*/ const Double_t *covI=0) const;
  92   void          GetDResDPosLine (Double_t *dXYZdP, Int_t ipnt) const;
  93   void          GetDResDPos(Double_t *dXYZdP, const Double_t *xyz, const Double_t *covI=0);
  94   void          GetDResDPos(Double_t *dXYZdP, Int_t ipnt);
  95   //
  96   Double_t*     GetPoint(int ip)                            const;
  97   Bool_t        Converged()                                 const {return fIter<fMaxIter;}
  98   //
  99   Double_t      Fit(Int_t extQ=0, Double_t extPT=-1,Double_t extPTerr=0);
 100   Double_t      FitLine();
 101   Double_t      FitHelix(Int_t extQ=0, Double_t extPT=-1,Double_t extPTerr=0);
 102   Bool_t        FitLineCrude();
 103   Bool_t        FitHelixCrude(Int_t imposedQ=0);
 104   //
 105   Int_t         GetParAxis()                                const {return fParAxis;}
 106   Int_t         GetAxID(Int_t id)                           const {return fkAxID  ? fkAxID[id] : -1;}
 107   Int_t         GetAxCID(Int_t id)                          const {return fkAxCID ? fkAxCID[id] : -1;}
 108   Int_t         GetFirst()                                  const {return fPntFirst;}
 109   Int_t         GetLast()                                   const {return fPntLast;}
 110   //
 111   Int_t         GetNParams()                                const {return IsFieldON() ? 5:4;}
 112   Bool_t        InvertPointsCovMat();
 113   //
 114   Int_t*     GetElsId() const {return fElsId;}
 115   Double_t*     GetElsDR() const {return fElsDR;}
 116   //
 117   Double_t*     GetCovI(Int_t ip)                           const {return fCovI + ip*6;}
 118   Double_t*     GetCovI()                                   const {return fCovI;}
 119   Double_t*     GetParams()                                 const {return (Double_t*)&fParams[0];}
 120   Double_t      GetParam(Int_t ip)                          const {return fParams[ip];}
 121   Double_t*     GetTs()                                     const {return (Double_t*)fCurT;}
 122   Double_t      GetT(Int_t ip)                              const {return fCurT[ip];}
 123   Double_t      GetLineOffset(Int_t axis)                   const;
 124   Double_t      GetLineSlope(Int_t axis)                    const;
 125   //
 126   Bool_t        IsELossON()                                 const {return TestBit(kELossBit)&&IsFieldON();}
 127   Bool_t        IsFitDone()                                 const {return TestBit(kFitDoneBit);}
 128   Bool_t        IsCovInv()                                  const {return TestBit(kCovInvBit);}
 129   Bool_t        IsCovIgnored()                              const {return TestBit(kIgnoreCovBit);}
 130   Int_t         GetMaxIterations()                          const {return fMaxIter;}
 131   Int_t         GetNIterations()                            const {return fIter;}
 132   Double_t      GetEps()                                    const {return fEps;}
 133   Double_t      GetMass()                                   const {return fMass;}
 134   //
 135   void          SetCharge(Int_t q=1)                              {fCharge = q<0 ? -1:1;}
 136   void          SetELossON(Bool_t v=kTRUE)                        {SetBit(kELossBit,v);}
 137   void          SetTypeCosmics(Bool_t v=kTRUE)                    {SetBit(kCosmicsBit,v);}
 138   void          SetTypeCollision(Bool_t v=kTRUE)                  {SetTypeCosmics(!v);}
 139   void          SetFitDone(Bool_t v=kTRUE)                        {SetBit(kFitDoneBit,v);}
 140   void          SetCovInv(Bool_t v=kTRUE)                         {SetBit(kCovInvBit,v);}
 141   void          SetIgnoreCov(Bool_t v=kTRUE)                      {SetBit(kIgnoreCovBit,v);}
 142   void          SetParAxis(Int_t ax);
 143   void          SetMaxIterations(Int_t n=20)                      {fMaxIter = n<2 ? 2:n;}
 144   void          SetEps(Double_t eps=1e-6)                         {fEps = eps<0 ? GetMachinePrec() : eps;}
 145   void          SetMass(Double_t m=0.13957)                       {fMass = m<5E-4 ? 5E-4 : m;}
 146   void          Reset();
 147   void          BuildMaterialLUT(Int_t ntri=3000);
 148   //
 149   virtual void  Print(Option_t *opt="")                                     const;
 150   //
 151   static void   GetNormal(Double_t *norm,const Float_t *covMat);
 152   //
 153  protected:
 154   void          InitAux();
 155   Double_t      GetMachinePrec();
 156   Int_t         ChoseParAxis()                                              const;
 157   Double_t      GetParPCALine(const Double_t *xyz, const Double_t *covI=0)  const;
 158   Double_t      GetParPCAHelix(const Double_t *xyz, const Double_t *covI=0) const;
 159   Double_t      GetParPCACircle(Double_t x, Double_t y)                     const;
 160   Double_t      GetHelixParAtR(Double_t r)                                  const;
 161   //
 162   void          GetDtDPosLine(Double_t *dtpos,/*const Double_t *xyz,*/  const Double_t *covI=0)  const;
 163   Double_t      GetDtDParamsLine(Double_t *dtparam,const Double_t *xyz, const Double_t *covI=0)  const;
 164   //
 165   Double_t      GetDRofELoss(Double_t t,Double_t cdip,Double_t rhoL,
 166                              const Double_t *normS, Double_t &p,Double_t &e) const;
 167   static Bool_t IsZero(Double_t v,Double_t threshold = 1e-16)     {return TMath::Abs(v)<threshold; }
 168
 169   //
 170  protected:
 171   const AliTrackPointArray *fPoints;               // current points
 172   AliParamSolver* fParSol;                         // solver for parametric linearized systems
 173   //
 174   Double_t  fBz;                                   // magnetic field
 175   Int_t     fCharge;                               // track charge +1=+, -1=-
 176   Int_t     fPntFirst;                             // first point to fit
 177   Int_t     fPntLast;                              // last point to fit
 178   Int_t     fNPBooked;                             // number of points booked
 179   Int_t     fParAxis;                              // parameterization axis
 180   Double_t *fCovI;                                 //! inverted cov.matrix for each point
 181   Double_t  fParams[kMaxParam];                    // fitted params
 182   Double_t  fParamsCov[kMaxParamSq];               // fit cov matrix
 183   Double_t  fChi2NDF;                              // fit chi2/NDF
 184   Int_t     fMaxIter;                              // max number of iterations
 185   Int_t     fIter;                                 // real number of iterations
 186   Double_t  fEps;                                  // precision
 187   Double_t  fMass;                                 // assumed particle mass for ELoss Calculation
 188   //
 189   const Int_t  *fkAxID;                            // axis IDs
 190   const Int_t  *fkAxCID;                           // axis combinations IDs
 191   //
 192   // internal storage
 193   Double_t *fCurT;                                 // track parameter for each point
 194   //
 195   // storage to account e-loss
 196   Int_t     fFirstPosT;                            // id of the first positive t index in fElsId
 197   Int_t     fNElsPnt;                              // number of e-loss layers seen by the track
 198   Int_t    *fElsId;                                // index of increasing t-ordering in the fCurT
 199   Double_t *fElsDR;                                // delta_Radius for each e-loss layer
 200   //
 201   static       Double_t fgRhoLITS[kMaxLrITS];      // <rho*L> for each material layer
 202   static const Double_t fgkRLayITS[kMaxLrITS];     // radii of material layers
 203   static const Double_t fgkZSpanITS[kMaxLrITS];    // half Z span of the material layer
 204   static const Int_t    fgkPassivLrITS[3];         // list of passive layer enums
 205   static const Int_t    fgkActiveLrITS[6];         // list of active layer enums
 206   static const Double_t fgkAlmostZero;             // tiny double
 207   static const Double_t fgkCQConv;                 // R = PT/Bz/fgkCQConv with GeV,kGauss,cm
 208   static const Int_t    fgkAxisID[3][3];           // permutations of axis
 209   static const Int_t    fgkAxisCID[3][6];          // cov matrix elements for axis selection
 210
 211   ClassDef(AliITSTPArrayFit,0);
 212 };
 213
 214 //____________________________________________________
 215 inline void AliITSTPArrayFit::GetPosition(Double_t *xyz, Int_t pnt) const
 216 {
 217   // track position at measured point pnt
 218   GetPosition(xyz,fCurT[pnt]);
 219 }
 220
 221 //____________________________________________________
 222 inline Double_t AliITSTPArrayFit::GetParPCA(const double *xyz, const double *covI) const
 223 {
 224   // get parameter for the point with least weighted distance to the point
 225   if (IsFieldON()) return GetParPCAHelix(xyz,covI);
 226   else             return GetParPCALine(xyz,covI);
 227 }
 228
 229 //____________________________________________________
 230 inline Double_t* AliITSTPArrayFit::GetPoint(Int_t ip) const
 231 {
 232   static double xyz[3];
 233   xyz[kX] = fPoints->GetX()[ip];
 234   xyz[kY] = fPoints->GetY()[ip];
 235   xyz[kZ] = fPoints->GetZ()[ip];
 236   return &xyz[0];
 237 }
 238
 239 //____________________________________________________
 240 inline Double_t AliITSTPArrayFit::Fit(Int_t extQ,Double_t extPT,Double_t extPTerr)
 241 {
 242   if (IsFieldON()) return FitHelix(extQ,extPT,extPTerr);
 243   else             return FitLine();
 244 }
 245
 246
 247 #endif