1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
16 //-----------------------------------------------------------------
17 // Implementation of the derived class for track residuals
18 // based on linear chi2 minimization (in approximation of
19 // small alignment angles and translations)
21 //-----------------------------------------------------------------
24 #include <TGeoMatrix.h>
27 #include "AliAlignObj.h"
28 #include "AliTrackPointArray.h"
29 #include "AliTrackResidualsFast.h"
31 ClassImp(AliTrackResidualsFast)
33 //______________________________________________________________________________
34 AliTrackResidualsFast::AliTrackResidualsFast():
38 // Default constructor
39 for (Int_t i = 0; i < 27; i++) fSum[i] = 0;
42 //______________________________________________________________________________
43 AliTrackResidualsFast::AliTrackResidualsFast(Int_t ntracks):
44 AliTrackResiduals(ntracks),
48 for (Int_t i = 0; i < 27; i++) fSum[i] = 0;
51 //______________________________________________________________________________
52 AliTrackResidualsFast::AliTrackResidualsFast(const AliTrackResidualsFast &res):
53 AliTrackResiduals(res),
57 for (Int_t i = 0; i < 27; i++) fSum[i] = res.fSum[i];
60 //______________________________________________________________________________
61 AliTrackResidualsFast &AliTrackResidualsFast::operator= (const AliTrackResidualsFast& res)
63 // Assignment operator
64 ((AliTrackResiduals *)this)->operator=(res);
65 for (Int_t i = 0; i < 27; i++) fSum[i] = res.fSum[i];
71 //______________________________________________________________________________
72 Bool_t AliTrackResidualsFast::Minimize()
74 // Implementation of fast linear Chi2
75 // based minimization of track residuals sum
76 for (Int_t i = 0; i < 27; i++) fSum[i] = 0;
81 for (Int_t itrack = 0; itrack < fLast; itrack++) {
82 if (!fVolArray[itrack] || !fTrackArray[itrack]) continue;
83 for (Int_t ipoint = 0; ipoint < fVolArray[itrack]->GetNPoints(); ipoint++) {
84 fVolArray[itrack]->GetPoint(p1,ipoint);
85 fTrackArray[itrack]->GetPoint(p2,ipoint);
94 // for (Int_t itrack = 0; itrack < fLast; itrack++) {
95 // if (!fVolArray[itrack] || !fTrackArray[itrack]) continue;
96 // for (Int_t ipoint = 0; ipoint < fVolArray[itrack]->GetNPoints(); ipoint++) {
97 // fVolArray[itrack]->GetPoint(p1,ipoint);
98 // fAlignObj->Transform(p1);
99 // fTrackArray[itrack]->GetPoint(p2,ipoint);
100 // Float_t residual = p2.GetResidual(p1,kFALSE);
104 // printf("Final chi2 = %f\n",chi2);
107 //______________________________________________________________________________
108 void AliTrackResidualsFast::AddPoints(AliTrackPoint &p, AliTrackPoint &pprime)
110 // Update the sums used for
111 // the linear chi2 minimization
112 Float_t xyz[3],xyzp[3];
113 Float_t cov[6],covp[6];
114 p.GetXYZ(xyz,cov); pprime.GetXYZ(xyzp,covp);
116 mcov(0,0) = cov[0]; mcov(0,1) = cov[1]; mcov(0,2) = cov[2];
117 mcov(1,0) = cov[1]; mcov(1,1) = cov[3]; mcov(1,2) = cov[4];
118 mcov(2,0) = cov[2]; mcov(2,1) = cov[4]; mcov(2,2) = cov[5];
119 TMatrixDSym mcovp(3);
120 mcovp(0,0) = covp[0]; mcovp(0,1) = covp[1]; mcovp(0,2) = covp[2];
121 mcovp(1,0) = covp[1]; mcovp(1,1) = covp[3]; mcovp(1,2) = covp[4];
122 mcovp(2,0) = covp[2]; mcovp(2,1) = covp[4]; mcovp(2,2) = covp[5];
123 TMatrixDSym msum = mcov + mcovp;
125 if (!msum.IsValid()) return;
128 sums(0,0) = (xyzp[0]-xyz[0]);
129 sums(1,0) = (xyzp[1]-xyz[1]);
130 sums(2,0) = (xyzp[2]-xyz[2]);
131 TMatrixD sumst = sums.T(); sums.T();
134 mf(0,0) = 1; mf(1,0) = 0; mf(2,0) = 0;
135 mf(0,1) = 0; mf(1,1) = 1; mf(2,1) = 0;
136 mf(0,2) = 0; mf(1,2) = 0; mf(2,2) = 1;
137 mf(0,3) = 0; mf(1,3) =-xyz[2]; mf(2,3) = xyz[1];
138 mf(0,4) = xyz[2]; mf(1,4) = 0; mf(2,4) =-xyz[0];
139 mf(0,5) =-xyz[1]; mf(1,5) = xyz[0]; mf(2,5) = 0;
140 TMatrixD mft = mf.T(); mf.T();
141 TMatrixD sums2 = mft * msum * sums;
143 TMatrixD smatrix = mft * msum * mf;
145 fSum[0] += smatrix(0,0);
146 fSum[1] += smatrix(0,1);
147 fSum[2] += smatrix(0,2);
148 fSum[3] += smatrix(0,3);
149 fSum[4] += smatrix(0,4);
150 fSum[5] += smatrix(0,5);
151 fSum[6] += smatrix(1,1);
152 fSum[7] += smatrix(1,2);
153 fSum[8] += smatrix(1,3);
154 fSum[9] += smatrix(1,4);
155 fSum[10]+= smatrix(1,5);
156 fSum[11]+= smatrix(2,2);
157 fSum[12]+= smatrix(2,3);
158 fSum[13]+= smatrix(2,4);
159 fSum[14]+= smatrix(2,5);
160 fSum[15]+= smatrix(3,3);
161 fSum[16]+= smatrix(3,4);
162 fSum[17]+= smatrix(3,5);
163 fSum[18]+= smatrix(4,4);
164 fSum[19]+= smatrix(4,5);
165 fSum[20]+= smatrix(5,5);
166 fSum[21] += sums2(0,0);
167 fSum[22] += sums2(1,0);
168 fSum[23] += sums2(2,0);
169 fSum[24] += sums2(3,0);
170 fSum[25] += sums2(4,0);
171 fSum[26] += sums2(5,0);
173 TMatrixD tmp = sumst * msum * sums;
179 //______________________________________________________________________________
180 Bool_t AliTrackResidualsFast::Update()
182 // Find the alignment parameters
183 // by using the already accumulated
185 TMatrixDSym smatrix(6);
188 smatrix(0,0) = fSum[0];
189 smatrix(0,1) = smatrix(1,0) = fSum[1];
190 smatrix(0,2) = smatrix(2,0) = fSum[2];
191 smatrix(0,3) = smatrix(3,0) = fSum[3];
192 smatrix(0,4) = smatrix(4,0) = fSum[4];
193 smatrix(0,5) = smatrix(5,0) = fSum[5];
194 smatrix(1,1) = fSum[6];
195 smatrix(1,2) = smatrix(2,1) = fSum[7];
196 smatrix(1,3) = smatrix(3,1) = fSum[8];
197 smatrix(1,4) = smatrix(4,1) = fSum[9];
198 smatrix(1,5) = smatrix(5,1) = fSum[10];
199 smatrix(2,2) = fSum[11];
200 smatrix(2,3) = smatrix(3,2) = fSum[12];
201 smatrix(2,4) = smatrix(4,2) = fSum[13];
202 smatrix(2,5) = smatrix(5,2) = fSum[14];
203 smatrix(3,3) = fSum[15];
204 smatrix(3,4) = smatrix(4,3) = fSum[16];
205 smatrix(3,5) = smatrix(5,3) = fSum[17];
206 smatrix(4,4) = fSum[18];
207 smatrix(4,5) = smatrix(5,4) = fSum[19];
208 smatrix(5,5) = fSum[20];
210 sums(0,0) = fSum[21]; sums(0,1) = fSum[22]; sums(0,2) = fSum[23];
211 sums(0,3) = fSum[24]; sums(0,4) = fSum[25]; sums(0,5) = fSum[26];
214 if (!smatrix.IsValid()) return kFALSE;
216 TMatrixD res = sums*smatrix;
217 fAlignObj->SetPars(res(0,0),res(0,1),res(0,2),
218 TMath::RadToDeg()*res(0,3),
219 TMath::RadToDeg()*res(0,4),
220 TMath::RadToDeg()*res(0,5));
221 TMatrixD tmp = res*sums.T();
222 fChi2 = fSumR - tmp(0,0);