Update raw2digits framework (Ch.Finck)
[u/mrichter/AliRoot.git] / HLT / hough / AliL3HoughKalmanTrack.cxx
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4 * Author: The ALICE Off-line Project. *
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14 **************************************************************************/
15
16//-------------------------------------------------------------------------
17// Implementation of the HLT TPC Hough Kalman track class
18//
19// Origin: Cvetan Cheshkov, CERN, Cvetan.Cheshkov@cern.ch
20//-------------------------------------------------------------------------
21
22#include "AliL3HoughKalmanTrack.h"
23
24#include "AliL3StandardIncludes.h"
25#include "AliL3HoughTrack.h"
26#include "AliL3HoughBaseTransformer.h"
27#include "AliL3HoughTransformerRow.h"
28#include "AliL3Histogram.h"
29
30Int_t CalcExternalParams(const AliL3HoughTrack& t, Double_t deltax, Double_t deltay, Double_t deltaeta, const Double_t zvertex, const Double_t xhit, Double_t xx[5]);
31
32ClassImp(AliL3HoughKalmanTrack)
33
34//____________________________________________________________________________
35AliL3HoughKalmanTrack::AliL3HoughKalmanTrack(const AliL3HoughTrack& t) throw (const Char_t *)
36 : AliTPCtrack()
37{
38 // The method constructs an AliL3HoughKalmanTrack object
39 // from an HLT Hough track
40
41 SetChi2(0.);
42 SetNumberOfClusters(t.GetLastRow()-t.GetFirstRow());
43 SetLabel(t.GetMCid());
44 SetFakeRatio(0.);
45 SetMass(0.13957);
46
47 fdEdx=0;
48 fAlpha = fmod((t.GetSector()+0.5)*(2*TMath::Pi()/18),2*TMath::Pi());
49 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
50 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
51
52 const Double_t xhit = 82.97;
53 const Double_t zvertex = t.GetFirstPointZ();
54 Double_t xx[5];
55 Double_t deltax = t.GetPterr();
56 Double_t deltay = t.GetPsierr();
57 Double_t deltaeta = t.GetTglerr();
58 if(CalcExternalParams(t,0,0,0,zvertex,xhit,xx)==0) throw "AliL3HoughKalmanTrack: conversion failed !\n";
59
60 //Filling of the track paramaters
61 fX=xhit;
62 fP0=xx[0];
63 fP1=xx[1];
64 fP2=xx[2];
65 fP3=xx[3];
66 fP4=xx[4];
67
68 //and covariance matrix
69 //For the moment estimate the covariance matrix numerically
70 Double_t xx1[5];
71 if(CalcExternalParams(t,deltax,0,0,zvertex,xhit,xx1)==0) throw "AliL3HoughKalmanTrack: conversion failed !\n";
72 Double_t xx2[5];
73 if(CalcExternalParams(t,0,deltay,0,zvertex,xhit,xx2)==0) throw "AliL3HoughKalmanTrack: conversion failed !\n";
74 Double_t xx3[5];
75 if(CalcExternalParams(t,0,0,deltaeta,zvertex,xhit,xx3)==0) throw "AliL3HoughKalmanTrack: conversion failed !\n";
76
77 Double_t dx1[5],dx2[5],dx3[5];
78 for(Int_t i=0;i<5;i++) {
79 dx1[i]=xx1[i]-xx[i];
80 dx2[i]=xx2[i]-xx[i];
81 dx3[i]=xx3[i]-xx[i];
82 }
83
84 fC00=dx1[0]*dx1[0]+dx2[0]*dx2[0];
85 fC22=dx1[2]*dx1[2]+dx2[2]*dx2[2];
86 fC44=dx1[4]*dx1[4]+dx2[4]*dx2[4];
87 fC20=dx1[2]*dx1[0]+dx2[2]*dx2[0];
88 fC40=dx1[4]*dx1[0]+dx2[4]*dx2[0];
89 fC42=dx1[4]*dx1[2]+dx2[4]*dx2[2];
90 fC33=dx3[3]*dx3[3];
91 fC11=dx3[1]*dx3[1];
92 fC31=dx3[3]*dx3[1];
93 fC10=fC30=fC21=fC41=fC32=fC43=0;
94 fC20=fC42=fC40=0;
95
96}
97
98//____________________________________________________________________________
99Int_t CalcExternalParams(const AliL3HoughTrack& t, Double_t deltax, Double_t deltay, Double_t deltaeta, const Double_t zvertex, const Double_t xhit, Double_t xx[5])
100{
101 // Translate the parameters of the Hough tracks into
102 // AliKalmanTrack paramters
103
104 //First get the emiision angle and track curvature
105 Double_t binx = t.GetBinX()+deltax;
106 Double_t biny = t.GetBinY()+deltay;
107 Double_t psi = atan((binx-biny)/(AliL3HoughTransformerRow::GetBeta1()-AliL3HoughTransformerRow::GetBeta2()));
108 Double_t kappa = 2.0*(binx*cos(psi)-AliL3HoughTransformerRow::GetBeta1()*sin(psi));
109 Double_t radius = 1./kappa;
110
111 //Local y coordinate
112 Double_t centerx = -1.*radius*sin(psi);
113 Double_t centery = radius*cos(psi);
114 Double_t aa = (xhit - centerx)*(xhit - centerx);
115 Double_t r2 = radius*radius;
116 if(aa > r2) return 0;
117 Double_t aa2 = sqrt(r2 - aa);
118 Double_t y1 = centery + aa2;
119 Double_t y2 = centery - aa2;
120 Double_t yhit = y1;
121 if(fabs(y2) < fabs(y1)) yhit = y2;
122
123 //Local z coordinate
124 Double_t stot = sqrt(xhit*xhit+yhit*yhit);
125 Double_t zhit;
126
127 //Lambda
128 Double_t eta=t.GetPseudoRapidity()+deltaeta;
129 Double_t theta = 2*atan(exp(-1.*eta));
130 Double_t tanl = 1./tan(theta);
131 zhit = zvertex + stot*tanl;
132
133 //Local sine of track azimuthal angle
134 Double_t sinbeta = centerx/radius;
135
136 xx[0] = yhit;
137 xx[1] = zhit;
138 xx[2] = sinbeta;
139 xx[3] = tanl;
140 xx[4] = kappa;
141 return 1;
142}