1 | #include <TMath.h>
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2 | #include <TVectorD.h>
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3 | #include <TVector3.h>
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4 | #include <TMatrixD.h>
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5 | #include <TMatrixDSym.h>
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6 | #include "VertexFit.h"
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7 | //
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8 | // Constructors
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9 | //
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10 | //
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11 | // Empty construction (to be used when adding tracks later with AddTrk() )
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12 | VertexFit::VertexFit()
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13 | {
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14 | fNtr = 0;
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15 | fRold = -1.0;
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16 | fVtxDone = kFALSE;
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17 | fVtxCst = kFALSE;
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18 | fxCst.ResizeTo(3);
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19 | fCovCst.ResizeTo(3, 3);
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20 | fCovCstInv.ResizeTo(3, 3);
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21 | fXv.ResizeTo(3);
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22 | fcovXv.ResizeTo(3, 3);
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23 | }
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24 | //
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25 | // Build from list of parameters and covariances
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26 | VertexFit::VertexFit(Int_t Ntr, TVectorD** trkPar, TMatrixDSym** trkCov)
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27 | {
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28 | fNtr = Ntr;
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29 | fRold = -1.0;
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30 | fVtxDone = kFALSE;
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31 | fVtxCst = kFALSE;
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32 | fxCst.ResizeTo(3);
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33 | fCovCst.ResizeTo(3, 3);
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34 | fCovCstInv.ResizeTo(3, 3);
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35 | fXv.ResizeTo(3);
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36 | fcovXv.ResizeTo(3, 3);
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37 | //
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38 | for (Int_t i = 0; i < fNtr; i++)
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39 | {
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40 | TVectorD pr = *trkPar[i];
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41 | fPar.push_back(new TVectorD(pr));
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42 | fParNew.push_back(new TVectorD(pr));
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43 | TMatrixDSym cv = *trkCov[i];
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44 | fCov.push_back(new TMatrixDSym(cv));
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45 | fCovNew.push_back(new TMatrixDSym(cv));
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46 | }
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47 | fChi2List.ResizeTo(fNtr);
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48 | //
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49 | }
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50 | //
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51 | // Build from ObsTrk list of tracks
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52 | VertexFit::VertexFit(Int_t Ntr, ObsTrk** track)
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53 | {
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54 | fNtr = Ntr;
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55 | fRold = -1.0;
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56 | fVtxDone = kFALSE;
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57 | fVtxCst = kFALSE;
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58 | fxCst.ResizeTo(3);
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59 | fCovCst.ResizeTo(3, 3);
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60 | fCovCstInv.ResizeTo(3, 3);
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61 | fXv.ResizeTo(3);
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62 | fcovXv.ResizeTo(3, 3);
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63 | //
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64 | fChi2List.ResizeTo(fNtr);
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65 | for (Int_t i = 0; i < fNtr; i++)
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66 | {
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67 | fPar.push_back(new TVectorD(track[i]->GetObsPar()));
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68 | fParNew.push_back(new TVectorD(track[i]->GetObsPar()));
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69 | fCov.push_back(new TMatrixDSym(track[i]->GetCov()));
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70 | fCovNew.push_back(new TMatrixDSym(track[i]->GetCov()));
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71 | }
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72 | }
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73 | //
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74 | // Destructor
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75 | //
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76 | void VertexFit::ResetWrkArrays()
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77 | {
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78 | Int_t N = (Int_t)ffi.size();
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79 | for (Int_t i = 0; i < N; i++)
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80 | {
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81 | if (fx0i[i]) { fx0i[i]->Clear(); delete fx0i[i]; }
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82 | if (fai[i]) { fai[i]->Clear(); delete fai[i]; }
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83 | if (fdi[i]) { fdi[i]->Clear(); delete fdi[i]; }
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84 | if (fAti[i]) { fAti[i]->Clear(); delete fAti[i]; }
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85 | if (fDi[i]) { fDi[i]->Clear(); delete fDi[i]; }
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86 | if (fWi[i]) { fWi[i]->Clear(); delete fWi[i]; }
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87 | if (fWinvi[i]){ fWinvi[i]->Clear(); delete fWinvi[i]; }
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88 | }
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89 | fa2i.clear();
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90 | fx0i.clear();
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91 | fai.clear();
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92 | fdi.clear();
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93 | fAti.clear();
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94 | fDi.clear();
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95 | fWi.clear();
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96 | fWinvi.clear();
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97 | }
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98 | VertexFit::~VertexFit()
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99 | {
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100 | fxCst.Clear();
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101 | fCovCst.Clear();
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102 | fCovCstInv.Clear();
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103 | fXv.Clear();
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104 | fcovXv.Clear();
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105 | fChi2List.Clear();
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106 | //
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107 | for (Int_t i = 0; i < fNtr; i++)
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108 | {
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109 | fPar[i]->Clear(); delete fPar[i];
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110 | fParNew[i]->Clear(); delete fParNew[i];
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111 | fCov[i]->Clear(); delete fCov[i];
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112 | fCovNew[i]->Clear(); delete fCovNew[i];
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113 | }
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114 | fPar.clear();
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115 | fParNew.clear();
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116 | fCov.clear();
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117 | fCovNew.clear();
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118 | //
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119 | ResetWrkArrays();
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120 | ffi.clear();
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121 | fNtr = 0;
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122 | }
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123 | //
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124 | Double_t VertexFit::FastRv(TVectorD p1, TVectorD p2)
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125 | {
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126 | //
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127 | // Find radius of minimum distance between two tracks
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128 | //
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129 | // p = (D,phi, C, z0, ct)
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130 | //
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131 | // Define arrays
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132 | //
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133 | Double_t C1 = p1(2);
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134 | Double_t C2 = p2(2);
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135 | Double_t ph1 = p1(1);
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136 | Double_t ph2 = p2(1);
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137 | TVectorD x0 = Fill_x0(p1);
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138 | TVectorD y0 = Fill_x0(p2);
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139 | TVectorD n = Fill_a(p1, 0.0);
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140 | n *= (2*C1);
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141 | TVectorD k = Fill_a(p2, 0.0);
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142 | k *= (2*C2);
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143 | //
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144 | // Setup and solve linear system
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145 | //
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146 | Double_t nn = 0; for (Int_t i = 0; i < 3; i++)nn += n(i) * n(i);
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147 | Double_t nk = 0; for (Int_t i = 0; i < 3; i++)nk += n(i) * k(i);
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148 | Double_t kk = 0; for (Int_t i = 0; i < 3; i++)kk += k(i) * k(i);
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149 | Double_t discr = nn * kk - nk * nk;
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150 | TMatrixDSym H(2);
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151 | H(0, 0) = kk;
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152 | H(0, 1) = nk;
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153 | H(1, 0) = H(0, 1);
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154 | H(1, 1) = nn;
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155 | TVectorD c(2);
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156 | c(0) = 0; for (Int_t i = 0; i < 3; i++)c(0) += n(i) * (y0(i) - x0(i));
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157 | c(1) = 0; for (Int_t i = 0; i < 3; i++)c(1) += -k(i) * (y0(i) - x0(i));
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158 | TVectorD smin = (H * c);
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159 | smin *= 1.0 / discr;
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160 | //
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161 | TVectorD X = x0 + smin(0) * n;
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162 | TVectorD Y = y0 + smin(1) * k;
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163 | //
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164 | // Higher order corrections
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165 | X(0) += -C1 * smin(0) * smin(0) * TMath::Sin(ph1);
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166 | X(1) += C1 * smin(0) * smin(0) * TMath::Cos(ph1);
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167 | Y(0) += -C2 * smin(1) * smin(1) * TMath::Sin(ph2);
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168 | Y(1) += C2 * smin(1) * smin(1) * TMath::Cos(ph2);
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169 | //
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170 | TVectorD Xavg = 0.5 * (X + Y);
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171 | //
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172 | //
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173 | return TMath::Sqrt(Xavg(0)*Xavg(0)+Xavg(1)*Xavg(1));
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174 | }
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175 | //
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176 | // Starting radius determination
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177 | Double_t VertexFit::StartRadius()
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178 | {
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179 | //
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180 | // Maximum impact parameter
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181 | Double_t Rd = 0;
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182 | for (Int_t i = 0; i < fNtr; i++)
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183 | {
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184 | TVectorD par = *fPar[i];
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185 | Double_t Dabs = TMath::Abs(par(0));
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186 | if (Dabs > Rd)Rd = Dabs;
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187 | }
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188 | //-----------------------------
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189 | //
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190 | // Find track pair with phi difference closest to pi/2
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191 | Int_t isel = 0; Int_t jsel = 0; // selected track indices
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192 | Double_t dSinMax = 0.0; // Max phi difference
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193 | for (Int_t i = 0; i < fNtr - 1; i++)
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194 | {
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195 | TVectorD pari = *fPar[i];
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196 | Double_t phi1 = pari(1);
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197 |
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198 | for (Int_t j = i + 1; j < fNtr; j++)
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199 | {
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200 | TVectorD parj = *fPar[j];
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201 | Double_t phi2 = parj(1);
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202 | Double_t Sindphi = TMath::Abs(TMath::Sin(phi2 - phi1));
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203 | if (Sindphi > dSinMax)
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204 | {
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205 | isel = i; jsel = j;
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206 | dSinMax = Sindphi;
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207 | }
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208 | }
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209 | }
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210 | //
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211 | //------------------------------------------
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212 | //
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213 | // Find radius of minimum distrance between tracks
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214 | TVectorD p1 = *fPar[isel];
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215 | TVectorD p2 = *fPar[jsel];
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216 | Double_t R = FastRv(p1, p2);
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217 | //
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218 | R = 0.9 * R + 0.1 * Rd; // Protect for overshoot
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219 | //
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220 | return R;
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221 | }
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222 | //
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223 | // Regularized symmetric matrix inversion
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224 | //
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225 | TMatrixDSym VertexFit::RegInv(TMatrixDSym& Min)
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226 | {
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227 | TMatrixDSym M = Min; // Decouple from input
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228 | Int_t N = M.GetNrows(); // Matrix size
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229 | TMatrixDSym D(N); D.Zero(); // Normaliztion matrix
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230 | TMatrixDSym R(N); // Normarized matrix
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231 | TMatrixDSym Rinv(N); // Inverse of R
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232 | TMatrixDSym Minv(N); // Inverse of M
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233 | //
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234 | // Check for 0's and normalize
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235 | for (Int_t i = 0; i < N; i++)
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236 | {
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237 | if (M(i, i) != 0.0) D(i, i) = 1. / TMath::Sqrt(TMath::Abs(M(i, i)));
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238 | else D(i, i) = 1.0;
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239 | }
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240 | R = M.Similarity(D);
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241 | //
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242 | // Recursive algorithms stops when N = 2
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243 | //
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244 | //****************
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245 | // case N = 2 ***
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246 | //****************
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247 | if (N == 2)
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248 | {
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249 | Double_t det = R(0, 0) * R(1, 1) - R(0, 1) * R(1, 0);
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250 | if (det == 0)
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251 | {
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252 | std::cout << "VertexFit::RegInv: null determinant for N = 2" << std::endl;
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253 | Rinv.Zero(); // Return null matrix
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254 | }
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255 | else
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256 | {
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257 | // invert matrix
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258 | Rinv(0, 0) = R(1, 1);
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259 | Rinv(0, 1) = -R(0, 1);
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260 | Rinv(1, 0) = Rinv(0, 1);
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261 | Rinv(1, 1) = R(0, 0);
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262 | Rinv *= 1. / det;
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263 | }
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264 | }
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265 | //****************
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266 | // case N > 2 ***
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267 | //****************
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268 | else
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269 | {
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270 | // Break up matrix
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271 | TMatrixDSym Q = R.GetSub(0, N - 2, 0, N - 2); // Upper left
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272 | TVectorD p(N - 1);
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273 | for (Int_t i = 0; i < N - 1; i++)p(i) = R(N - 1, i);
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274 | Double_t q = R(N - 1, N - 1);
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275 | //Invert pieces and re-assemble
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276 | TMatrixDSym Ainv(N - 1);
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277 | TMatrixDSym A(N - 1);
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278 | if (TMath::Abs(q) > 1.0e-15)
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279 | {
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280 | // Case |q| > 0
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281 | Ainv.Rank1Update(p, -1.0 / q);
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282 | Ainv += Q;
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283 | A = RegInv(Ainv); // Recursive call
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284 | TMatrixDSub(Rinv, 0, N - 2, 0, N - 2) = A;
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285 | //
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286 | TVectorD b = (-1.0 / q) * (A * p);
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287 | for (Int_t i = 0; i < N - 1; i++)
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288 | {
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289 | Rinv(N - 1, i) = b(i);
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290 | Rinv(i, N - 1) = b(i);
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291 | }
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292 | //
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293 | Double_t pdotb = 0.;
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294 | for (Int_t i = 0; i < N - 1; i++)pdotb += p(i) * b(i);
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295 | Double_t c = (1.0 - pdotb) / q;
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296 | Rinv(N - 1, N - 1) = c;
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297 | }
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298 | else
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299 | {
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300 | // case q = 0
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301 | TMatrixDSym Qinv = RegInv(Q); // Recursive call
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302 | Double_t a = Qinv.Similarity(p);
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303 | Double_t c = -1.0 / a;
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304 | Rinv(N - 1, N - 1) = c;
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305 | //
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306 | TVectorD b = (1.0 / a) * (Qinv * p);
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307 | for (Int_t i = 0; i < N - 1; i++)
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308 | {
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309 | Rinv(N - 1, i) = b(i);
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310 | Rinv(i, N - 1) = b(i);
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311 | }
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312 | //
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313 | A.Rank1Update(p, -1 / a);
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314 | A += Q;
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315 | A.Similarity(Qinv);
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316 | TMatrixDSub(Rinv, 0, N - 2, 0, N - 2) = A;
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317 | }
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318 | }
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319 | Minv = Rinv.Similarity(D);
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320 | return Minv;
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321 | }
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322 | //
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323 | //
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324 | //
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325 | TMatrixD VertexFit::Fill_A(TVectorD par, Double_t phi)
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326 | {
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327 | //
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328 | // Derivative of track 3D position vector with respect to track parameters at constant phase
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329 | //
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330 | // par = vector of track parameters
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331 | // phi = phase
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332 | //
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333 | TMatrixD A(3, 5);
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334 | //
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335 | // Decode input arrays
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336 | //
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337 | Double_t D = par(0);
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338 | Double_t p0 = par(1);
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339 | Double_t C = par(2);
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340 | Double_t z0 = par(3);
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341 | Double_t ct = par(4);
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342 | //
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343 | // Fill derivative matrix dx/d alpha
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344 | // D
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345 | A(0, 0) = -TMath::Sin(p0);
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346 | A(1, 0) = TMath::Cos(p0);
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347 | A(2, 0) = 0.0;
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348 | // phi0
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349 | A(0, 1) = -D * TMath::Cos(p0) + (TMath::Cos(phi + p0) - TMath::Cos(p0)) / (2 * C);
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350 | A(1, 1) = -D * TMath::Sin(p0) + (TMath::Sin(phi + p0) - TMath::Sin(p0)) / (2 * C);
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351 | A(2, 1) = 0.0;
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352 | // C
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353 | A(0, 2) = -(TMath::Sin(phi + p0) - TMath::Sin(p0)) / (2 * C * C);
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354 | A(1, 2) = (TMath::Cos(phi + p0) - TMath::Cos(p0)) / (2 * C * C);
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355 | A(2, 2) = -ct * phi / (2 * C * C);
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356 | // z0
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357 | A(0, 3) = 0.0;
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358 | A(1, 3) = 0.0;
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359 | A(2, 3) = 1.0;
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360 | // ct = lambda
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361 | A(0, 4) = 0.0;
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362 | A(1, 4) = 0.0;
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363 | A(2, 4) = phi / (2 * C);
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364 | //
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365 | return A;
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366 | }
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367 | //
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368 | TVectorD VertexFit::Fill_a(TVectorD par, Double_t phi)
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369 | {
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370 | //
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371 | // Derivative of track 3D position vector with respect to phase at constant track parameters
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372 | //
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373 | // par = vector of track parameters
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374 | // phi = phase
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375 | //
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376 | TVectorD a(3);
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377 | //
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378 | // Decode input arrays
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379 | //
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380 | Double_t D = par(0);
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381 | Double_t p0 = par(1);
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382 | Double_t C = par(2);
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383 | Double_t z0 = par(3);
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384 | Double_t ct = par(4);
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385 | //
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386 | a(0) = TMath::Cos(phi + p0) / (2 * C);
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387 | a(1) = TMath::Sin(phi + p0) / (2 * C);
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388 | a(2) = ct / (2 * C);
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389 | //
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390 | return a;
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391 | }
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392 | //
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393 | TVectorD VertexFit::Fill_x0(TVectorD par)
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394 | {
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395 | //
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396 | // Calculate track 3D position at R = |D| (minimum approach to z-axis)
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397 | //
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398 | TVectorD x0(3);
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399 | //
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400 | // Decode input arrays
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401 | //
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402 | Double_t D = par(0);
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403 | Double_t p0 = par(1);
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404 | Double_t C = par(2);
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405 | Double_t z0 = par(3);
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406 | Double_t ct = par(4);
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407 | //
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408 | x0(0) = -D * TMath::Sin(p0);
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409 | x0(1) = D * TMath::Cos(p0);
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410 | x0(2) = z0;
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411 | //
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412 | return x0;
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413 | }
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414 | //
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415 | TVectorD VertexFit::Fill_x(TVectorD par, Double_t phi)
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416 | {
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417 | //
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418 | // Calculate track 3D position for a given phase, phi
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419 | //
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420 | TVectorD x(3);
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421 | //
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422 | // Decode input arrays
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423 | //
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424 | Double_t D = par(0);
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425 | Double_t p0 = par(1);
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426 | Double_t C = par(2);
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---|
427 | Double_t z0 = par(3);
|
---|
428 | Double_t ct = par(4);
|
---|
429 | //
|
---|
430 | TVectorD x0 = Fill_x0(par);
|
---|
431 | x(0) = x0(0) + (TMath::Sin(phi + p0) - TMath::Sin(p0)) / (2 * C);
|
---|
432 | x(1) = x0(1) - (TMath::Cos(phi + p0) - TMath::Cos(p0)) / (2 * C);
|
---|
433 | x(2) = x0(2) + ct * phi / (2 * C);
|
---|
434 | //
|
---|
435 | return x;
|
---|
436 | }
|
---|
437 | //
|
---|
438 | void VertexFit::UpdateTrkArrays(Int_t i)
|
---|
439 | {
|
---|
440 | //
|
---|
441 | // Get track parameters and their covariance
|
---|
442 | TVectorD par = *fParNew[i];
|
---|
443 | TMatrixDSym Cov = *fCov[i];
|
---|
444 | //
|
---|
445 | // Fill all track related work arrays arrays
|
---|
446 | Double_t fs = ffi[i]; // Get phase
|
---|
447 | TVectorD xs = Fill_x(par, fs);
|
---|
448 | fx0i.push_back(new TVectorD(xs)); // Start helix position
|
---|
449 | //
|
---|
450 | TMatrixD A = Fill_A(par, fs); // A = dx/da = derivatives wrt track parameters
|
---|
451 | TMatrixD At(TMatrixD::kTransposed, A); // A transposed
|
---|
452 | fAti.push_back(new TMatrixD(At)); // Store A'
|
---|
453 | TVectorD di = A * (par - *fPar[i]); // x-shift
|
---|
454 | fdi.push_back(new TVectorD(di)); // Store x-shift
|
---|
455 | TMatrixDSym Winv = Cov.Similarity(A); // W^-1 = A*C*A'
|
---|
456 | fWinvi.push_back(new TMatrixDSym(Winv)); // Store W^-1 matrix
|
---|
457 | //
|
---|
458 | TMatrixDSym W = RegInv(Winv); // W = (A*C*A')^-1
|
---|
459 | fWi.push_back(new TMatrixDSym(W)); // Store W matrix
|
---|
460 | //
|
---|
461 | TVectorD a = Fill_a(par, fs); // a = dx/ds = derivatives wrt phase
|
---|
462 | fai.push_back(new TVectorD(a)); // Store a
|
---|
463 | //
|
---|
464 | Double_t a2 = W.Similarity(a);
|
---|
465 | fa2i.push_back(a2); // Store a2
|
---|
466 | //
|
---|
467 | // Build D matrix
|
---|
468 | TMatrixDSym B(3);
|
---|
469 | B.Rank1Update(a, -1. / a2);
|
---|
470 | B.Similarity(W);
|
---|
471 | TMatrixDSym Ds = W + B; // D matrix
|
---|
472 | fDi.push_back(new TMatrixDSym(Ds)); // Store D matrix
|
---|
473 | }
|
---|
474 | //
|
---|
475 | void VertexFit::VertexFitter()
|
---|
476 | {
|
---|
477 | //std::cout << "VertexFitter: just in" << std::endl;
|
---|
478 | if (fNtr < 2 && !fVtxCst){
|
---|
479 | std::cout << "VertexFit::VertexFitter - Method called with less than 2 tracks - Aborting " << std::endl;
|
---|
480 | std::exit(1);
|
---|
481 | }
|
---|
482 | //
|
---|
483 | // Vertex fit
|
---|
484 | //
|
---|
485 | // Initial variable definitions
|
---|
486 | TVectorD x(3);
|
---|
487 | TMatrixDSym covX(3);
|
---|
488 | Double_t Chi2 = 0;
|
---|
489 | TVectorD x0 = fXv; // If previous fit done
|
---|
490 | if (fRold < 0.0) {
|
---|
491 | // External constraint
|
---|
492 | if (fVtxCst) fRold = TMath::Sqrt(fxCst(0) * fxCst(0) + fxCst(1) * fxCst(1));
|
---|
493 | // No constraint
|
---|
494 | else for (Int_t i = 0; i < 3; i++)x0(i) = 1000.; // Set to arbitrary large value
|
---|
495 | }
|
---|
496 | //
|
---|
497 | // Starting vertex radius approximation
|
---|
498 | //
|
---|
499 | Double_t R = fRold; // Use previous fit if available
|
---|
500 | if (R < 0.0) R = StartRadius(); // Rough vertex estimate
|
---|
501 | //std::cout << "Start radius: " << R << std::endl;
|
---|
502 | //
|
---|
503 | // Iteration properties
|
---|
504 | //
|
---|
505 | Int_t Ntry = 0;
|
---|
506 | Int_t TryMax = 100;
|
---|
507 | Double_t eps = 1.0e-9; // vertex stability
|
---|
508 | Double_t epsi = 1000.;
|
---|
509 | //
|
---|
510 | // Iteration loop
|
---|
511 | while (epsi > eps && Ntry < TryMax) // Iterate until found vertex is stable
|
---|
512 | {
|
---|
513 | // Initialize arrays
|
---|
514 | x.Zero();
|
---|
515 | TVectorD cterm(3); TMatrixDSym H(3); TMatrixDSym DW1D(3);
|
---|
516 | covX.Zero(); // Reset vertex covariance
|
---|
517 | cterm.Zero(); // Reset constant term
|
---|
518 | H.Zero(); // Reset H matrix
|
---|
519 | DW1D.Zero();
|
---|
520 | //
|
---|
521 | // Reset work arrays
|
---|
522 | //
|
---|
523 | ResetWrkArrays();
|
---|
524 | //
|
---|
525 | // Start loop on tracks
|
---|
526 | //
|
---|
527 | for (Int_t i = 0; i < fNtr; i++)
|
---|
528 | {
|
---|
529 | // Get track helix parameters and their covariance matrix
|
---|
530 | TVectorD par = *fPar[i];
|
---|
531 | TMatrixDSym Cov = *fCov[i];
|
---|
532 | //
|
---|
533 | // For first iteration only
|
---|
534 | Double_t fs;
|
---|
535 | if (Ntry <= 0) // Initialize all phases on first pass
|
---|
536 | {
|
---|
537 | Double_t D = par(0);
|
---|
538 | Double_t C = par(2);
|
---|
539 | Double_t arg = TMath::Max(1.0e-6, (R * R - D * D) / (1 + 2 * C * D));
|
---|
540 | fs = 2 * TMath::ASin(C * TMath::Sqrt(arg));
|
---|
541 | ffi.push_back(fs);
|
---|
542 | }
|
---|
543 | //
|
---|
544 | // Update track related arrays
|
---|
545 | //
|
---|
546 | UpdateTrkArrays(i);
|
---|
547 | TMatrixDSym Ds = *fDi[i];
|
---|
548 | TMatrixDSym Winv = *fWinvi[i];
|
---|
549 | TMatrixDSym DsW1Ds = Winv.Similarity(Ds); // Service matrix to calculate covX
|
---|
550 | //
|
---|
551 | // Update global arrays
|
---|
552 | DW1D += DsW1Ds;
|
---|
553 | // Update hessian
|
---|
554 | H += Ds;
|
---|
555 | // update constant term
|
---|
556 | TVectorD xs = *fx0i[i] - *fdi[i];
|
---|
557 | TVectorD xx0 = *fx0i[i];
|
---|
558 | /*
|
---|
559 | std::cout << "Iter. " << Ntry << ", trk " << i << ", x= "
|
---|
560 | << xx0(0) << ", " << xx0(1) << ", " << xx0(2)<<
|
---|
561 | ", ph0= "<<par(1)<< std::endl;
|
---|
562 | */
|
---|
563 | cterm += Ds * xs;
|
---|
564 | } // End loop on tracks
|
---|
565 | // Some additions in case of external constraints
|
---|
566 | if (fVtxCst) {
|
---|
567 | H += fCovCstInv;
|
---|
568 | cterm += fCovCstInv * fxCst;
|
---|
569 | DW1D += fCovCstInv;
|
---|
570 | }
|
---|
571 | //
|
---|
572 | // update vertex position
|
---|
573 | TMatrixDSym H1 = RegInv(H);
|
---|
574 | x = H1 * cterm;
|
---|
575 | //
|
---|
576 | // Update vertex covariance
|
---|
577 | covX = DW1D.Similarity(H1);
|
---|
578 | //
|
---|
579 | // Update phases and chi^2
|
---|
580 | Chi2 = 0.0;
|
---|
581 | for (Int_t i = 0; i < fNtr; i++)
|
---|
582 | {
|
---|
583 | TVectorD lambda = (*fDi[i]) * (*fx0i[i] - x - *fdi[i]);
|
---|
584 | TMatrixDSym Wm1 = *fWinvi[i];
|
---|
585 | fChi2List(i) = Wm1.Similarity(lambda);
|
---|
586 | Chi2 += fChi2List(i);
|
---|
587 | TVectorD a = *fai[i];
|
---|
588 | TVectorD b = (*fWi[i]) * (x - (*fx0i[i]));
|
---|
589 | for (Int_t j = 0; j < 3; j++)ffi[i] += a(j) * b(j) / fa2i[i];
|
---|
590 | TVectorD newPar = *fPar[i] - ((*fCov[i]) * (*fAti[i])) * lambda;
|
---|
591 | fParNew[i] = new TVectorD(newPar);
|
---|
592 | }
|
---|
593 | // Add external constraint to Chi2
|
---|
594 | if (fVtxCst) Chi2 += fCovCstInv.Similarity(x - fxCst);
|
---|
595 | //
|
---|
596 | TVectorD dx = x - x0;
|
---|
597 | x0 = x;
|
---|
598 | // update vertex stability
|
---|
599 | TMatrixDSym Hess = RegInv(covX);
|
---|
600 | epsi = Hess.Similarity(dx);
|
---|
601 | Ntry++;
|
---|
602 | //
|
---|
603 | // Store result
|
---|
604 | //
|
---|
605 | fXv = x; // Vertex position
|
---|
606 | fcovXv = covX; // Vertex covariance
|
---|
607 | fChi2 = Chi2; // Vertex fit Chi2
|
---|
608 | //std::cout << "Found vertex " << fXv(0) << ", " << fXv(1) << ", " << fXv(2) << std::endl;
|
---|
609 | } // end of iteration loop
|
---|
610 | //
|
---|
611 | fVtxDone = kTRUE; // Set fit completion flag
|
---|
612 | fRold = TMath::Sqrt(fXv(0)*fXv(0) + fXv(1)*fXv(1)); // Store fit radius
|
---|
613 | //
|
---|
614 | }
|
---|
615 | //
|
---|
616 | // Return fit vertex
|
---|
617 | TVectorD VertexFit::GetVtx()
|
---|
618 | {
|
---|
619 | if (!fVtxDone) VertexFitter();
|
---|
620 | return fXv;
|
---|
621 | }
|
---|
622 | //
|
---|
623 | // Return fit vertex covariance
|
---|
624 | TMatrixDSym VertexFit::GetVtxCov()
|
---|
625 | {
|
---|
626 | if (!fVtxDone) VertexFitter();
|
---|
627 | return fcovXv;
|
---|
628 | }
|
---|
629 | //
|
---|
630 | // Return fit vertex chi2
|
---|
631 | Double_t VertexFit::GetVtxChi2()
|
---|
632 | {
|
---|
633 | if (!fVtxDone) VertexFitter();
|
---|
634 | return fChi2;
|
---|
635 | }
|
---|
636 | //
|
---|
637 | // Return array of chi2 contributions from each track
|
---|
638 | TVectorD VertexFit::GetVtxChi2List()
|
---|
639 | {
|
---|
640 | if (!fVtxDone) VertexFitter();
|
---|
641 | return fChi2List;
|
---|
642 | }
|
---|
643 | //
|
---|
644 | // Handle tracks/constraints
|
---|
645 | void VertexFit::AddVtxConstraint(TVectorD xv, TMatrixDSym cov) // Add gaussian vertex constraint
|
---|
646 | {
|
---|
647 | //std::cout << "VertexFit::AddVtxConstraint: Not implemented yet" << std::endl;
|
---|
648 | fVtxCst = kTRUE; // Vertex constraint flag
|
---|
649 | fxCst = xv; // Constraint value
|
---|
650 | fCovCst = cov; // Constraint covariance
|
---|
651 | fCovCstInv = cov;
|
---|
652 | fCovCstInv.Invert(); // Its inverse
|
---|
653 | //
|
---|
654 | // Set starting vertex as external constraint
|
---|
655 | fXv = fxCst;
|
---|
656 | fcovXv = fCovCst;
|
---|
657 | }
|
---|
658 | //
|
---|
659 | // Adding tracks one by one
|
---|
660 | void VertexFit::AddTrk(TVectorD *par, TMatrixDSym *Cov) // Add track to input list
|
---|
661 | {
|
---|
662 | fNtr++;
|
---|
663 | fChi2List.ResizeTo(fNtr); // Resize chi2 array
|
---|
664 | fPar.push_back(par); // add new track
|
---|
665 | fCov.push_back(Cov);
|
---|
666 | fParNew.push_back(par); // add new track
|
---|
667 | fCovNew.push_back(Cov);
|
---|
668 | //
|
---|
669 | // Reset previous vertex temp arrays
|
---|
670 | ResetWrkArrays();
|
---|
671 | ffi.clear();
|
---|
672 | fVtxDone = kFALSE; // Reset vertex done flag
|
---|
673 | }
|
---|
674 | //
|
---|
675 | // Removing tracks one by one
|
---|
676 | void VertexFit::RemoveTrk(Int_t iTrk) // Remove iTrk track
|
---|
677 | {
|
---|
678 | fNtr--;
|
---|
679 | fChi2List.Clear();
|
---|
680 | fChi2List.ResizeTo(fNtr); // Resize chi2 array
|
---|
681 | fPar.erase(fPar.begin() + iTrk); // Remove track
|
---|
682 | fCov.erase(fCov.begin() + iTrk);
|
---|
683 | fParNew.erase(fParNew.begin() + iTrk); // Remove track
|
---|
684 | fCovNew.erase(fCovNew.begin() + iTrk);
|
---|
685 | //
|
---|
686 | // Reset previous vertex temp arrays
|
---|
687 | ResetWrkArrays();
|
---|
688 | ffi.clear();
|
---|
689 | fVtxDone = kFALSE; // Reset vertex done flag
|
---|
690 | }
|
---|