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 *
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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
19 // The minimization relies on the fact that the alignment parameters
20 // (angles and translations) are small.
21 // TLinearFitter used for minimization
22 // Possibility to fix Paramaters
23 // FixParameter()ReleaseParameter();
24 // Possibility to define fraction of outliers to be skipped
26 // marian.ivanov@cern.ch
28 //-----------------------------------------------------------------
31 #include <TGeoMatrix.h>
34 #include "AliAlignObj.h"
35 #include "AliTrackPointArray.h"
36 #include "AliTrackResidualsLinear.h"
37 #include "AliAlignObj.h"
38 #include "TLinearFitter.h"
39 #include "TDecompSVD.h"
41 ClassImp(AliTrackResidualsLinear)
43 //______________________________________________________________________________
44 AliTrackResidualsLinear::AliTrackResidualsLinear():AliTrackResiduals()
46 // Default constructor
50 for (Int_t ipar=0; ipar<6; ipar++){
51 fBFixed[ipar] = kFALSE;
57 //______________________________________________________________________________
58 AliTrackResidualsLinear::AliTrackResidualsLinear(Int_t ntracks):
59 AliTrackResiduals(ntracks)
62 fFitter = new TLinearFitter(6,"hyp6");
65 for (Int_t ipar=0; ipar<6; ipar++){
66 fBFixed[ipar] = kFALSE;
72 //______________________________________________________________________________
73 AliTrackResidualsLinear::AliTrackResidualsLinear(const AliTrackResidualsLinear &res):
74 AliTrackResiduals(res)
78 fFitter = new TLinearFitter(*(res.fFitter));
79 for (Int_t ipar=0; ipar<6; ipar++){
80 fBFixed[ipar] = res.fBFixed[ipar];
81 fFixed[ipar] = res.fFixed[ipar];
82 fParams[ipar] = res.fParams[ipar];
84 fChi2Orig = res.fChi2Orig;
87 //______________________________________________________________________________
88 AliTrackResidualsLinear &AliTrackResidualsLinear::operator= (const AliTrackResidualsLinear& res)
90 // Assignment operator
91 ((AliTrackResiduals *)this)->operator=(res);
94 //______________________________________________________________________________
95 AliTrackResidualsLinear::~AliTrackResidualsLinear()
104 //______________________________________________________________________________
105 Bool_t AliTrackResidualsLinear::Minimize()
107 // Implementation of fast linear Chi2 minimizer
108 // based on TLinear fitter
110 if (!fFitter) fFitter = new TLinearFitter(6,"hyp6");
111 fFitter->StoreData(kTRUE);
112 fFitter->ClearPoints();
115 for (Int_t itrack = 0; itrack < fLast; itrack++) {
116 if (!fVolArray[itrack] || !fTrackArray[itrack]) continue;
117 for (Int_t ipoint = 0; ipoint < fVolArray[itrack]->GetNPoints(); ipoint++) {
118 fVolArray[itrack]->GetPoint(p1,ipoint);
119 fTrackArray[itrack]->GetPoint(p2,ipoint);
123 Bool_t isOK = Update();
124 if (!isOK) return isOK;
127 fAlignObj->GetMatrix(matrix);
133 //______________________________________________________________________________
134 void AliTrackResidualsLinear::AddPoints(AliTrackPoint &p, AliTrackPoint &pprime)
137 // add points to linear fitter - option with correlation betwee measurement in different dimensions
139 // pprime - track extrapolation point
141 Float_t xyz[3],xyzp[3];
142 Float_t cov[6],covp[6];
143 p.GetXYZ(xyz,cov); pprime.GetXYZ(xyzp,covp);
146 TMatrixD mcov(3,3); // local point covariance
147 mcov(0,0) = cov[0]; mcov(0,1) = cov[1]; mcov(0,2) = cov[2];
148 mcov(1,0) = cov[1]; mcov(1,1) = cov[3]; mcov(1,2) = cov[4];
149 mcov(2,0) = cov[2]; mcov(2,1) = cov[4]; mcov(2,2) = cov[5];
150 TMatrixD mcovp(3,3); // extrapolation point covariance
151 mcovp(0,0) = covp[0]; mcovp(0,1) = covp[1]; mcovp(0,2) = covp[2];
152 mcovp(1,0) = covp[1]; mcovp(1,1) = covp[3]; mcovp(1,2) = covp[4];
153 mcovp(2,0) = covp[2]; mcovp(2,1) = covp[4]; mcovp(2,2) = covp[5];
156 if (!mcov.IsValid()) return;
157 TMatrixD mcovBack = mcov; // for debug purposes
161 TDecompSVD svd(mcov); // mcov = svd.fU * covDiagonal * svd.fV.Invert
162 if (!svd.Decompose()) return; // decomposition failed
163 TMatrixD matrixV = svd.GetV(); // transformation matrix to diagonalize covariance matrix
164 Double_t covDiagonal[3] = {svd.GetSig()[0],svd.GetSig()[1],svd.GetSig()[2]}; // diagonalized covariance matrix
167 TMatrixD deltaR(3,1);
168 deltaR(0,0) = (xyzp[0]-xyz[0]);
169 deltaR(1,0) = (xyzp[1]-xyz[1]);
170 deltaR(2,0) = (xyzp[2]-xyz[2]);
172 // parametrization matrix
174 TMatrixD mparam(3,6);
175 mparam(0,0) = 1; mparam(1,0) = 0; mparam(2,0) = 0; // xshift
176 mparam(0,1) = 0; mparam(1,1) = 1; mparam(2,1) = 0; // yshift
177 mparam(0,2) = 0; mparam(1,2) = 0; mparam(2,2) = 1; // zshift
178 mparam(0,3) = 0; mparam(1,3) =-xyz[2]; mparam(2,3) = xyz[1]; // x rotation
179 mparam(0,4) = xyz[2]; mparam(1,4) = 0; mparam(2,4) =-xyz[0]; // y rotation
180 mparam(0,5) =-xyz[1]; mparam(1,5) = xyz[0]; mparam(2,5) = 0; // z rotation
183 TMatrixD deltaT(matrixV, TMatrixD::kTransposeMult, deltaR); // tranformed delta
184 TMatrixD mparamT(matrixV,TMatrixD::kTransposeMult, mparam); // tranformed linear transformation
189 // covDiag = U^-1 * mcov * V -- diagonalization of covariance matrix
191 TMatrixD matrixU = svd.GetU(); // transformation matrix to diagonalize covariance matrix
192 TMatrixD matrixUI= svd.GetU();
195 TMatrixD test0 = matrixUI*matrixV; // test matrix - should be unit matrix
196 TMatrixD test1 = matrixUI*mcovBack*matrixV; // test matrix - diagonal - should be diagonal with covDiagonal on diag
197 TMatrixD test2 = matrixU.T()*matrixV; // test ortogonality - shoul be unit
198 printf("Test matrix 2 - should be unit\n");
200 printf("Test matrix 0 - should be unit\n");
202 printf("Test matrix 1 - should be diagonal\n");
204 printf("Diagonal matrix\n");
205 svd.GetSig().Print();
206 printf("Original param matrix\n");
208 printf("Rotated param matrix\n");
213 for (Int_t idim = 0; idim<3; idim++){
214 Double_t yf; // input points to fit in TLinear fitter
215 Double_t xf[6]; // input points to fit
217 for (Int_t ipar =0; ipar<6; ipar++) xf[ipar] = mparamT(idim,ipar);
218 if (covDiagonal[idim]>0.){
219 fFitter->AddPoint(xf,yf, TMath::Sqrt(1/covDiagonal[idim]));
222 fChi2Orig += (yf*yf)*covDiagonal[idim];
227 //______________________________________________________________________________
228 Bool_t AliTrackResidualsLinear::Update()
230 // Find the alignment parameters
231 // using TLinear fitter + fill data containers
236 // TLinear fitter put as first parameter offset - fixing parameter shifted by one
238 fFitter->FixParameter(0);
239 for (Int_t ipar =0; ipar<6; ipar++){
240 if (fBFixed[ipar]) fFitter->FixParameter(ipar+1,fFixed[ipar]);
243 fFitter->EvalRobust(fFraction);
248 fFitter->ReleaseParameter(0);
249 for (Int_t ipar=0; ipar<7; ipar++) {
250 if (fBFixed[ipar]) fFitter->ReleaseParameter(ipar+1);
255 fChi2 = fFitter->GetChisquare();
258 fFitter->GetParameters(vector);
259 fParams[0] = vector[1];
260 fParams[1] = vector[2];
261 fParams[2] = vector[3];
262 fParams[3] = vector[4];
263 fParams[4] = vector[5];
264 fParams[5] = vector[6];
266 fAlignObj->SetPars(fParams[0], fParams[1], fParams[2],
267 TMath::RadToDeg()*fParams[3],
268 TMath::RadToDeg()*fParams[4],
269 TMath::RadToDeg()*fParams[5]);