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 **************************************************************************/
15 //------------------------------------------------------------------
16 // this class is used for a simple
17 // track fitting using the polynom
18 // bending in both directions are allowed
19 //-----------------------------------------------------------------
22 #include "AliTPCpolyTrack.h"
25 ClassImp(AliTPCpolyTrack)
28 AliTPCpolyTrack::AliTPCpolyTrack()
54 void AliTPCpolyTrack::Reset()
58 fSumX = fSumX2= fSumX3=fSumX4 = fSumY=fSumYX=fSumYX2=fSumZ=fSumZX=fSumZX2=fSumW =0;
62 void AliTPCpolyTrack::AddPoint(Double_t x, Double_t y, Double_t z,Double_t sy, Double_t sz)
75 Double_t w = 2./(sy+sz);
101 void AliTPCpolyTrack::UpdateParameters()
105 //Update fit parameters
107 Fit2(fSumY,fSumYX,fSumYX2,fSumX,fSumX2,fSumX3,fSumX4,fSumW,fA,fB,fC);
108 // Fit2(fSumZ,fSumZX,fSumZX2,fSumX,fSumX2,fSumX3,fSumX4,fNPoints,fD,fE,fF);
109 Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF);
113 Fit1(fSumY,fSumYX,fSumX,fSumX2,fSumW,fA,fB,fC);
114 Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF);
118 void AliTPCpolyTrack::UpdateParameters(Int_t ny, Int_t nz)
122 //Update fit parameters
124 Fit2(fSumY,fSumYX,fSumYX2,fSumX,fSumX2,fSumX3,fSumX4,fSumW,fA,fB,fC);
127 Fit1(fSumY,fSumYX,fSumX,fSumX2,fSumW,fA,fB,fC);
130 Fit2(fSumZ,fSumZX,fSumZX2,fSumX,fSumX2,fSumX3,fSumX4,fNPoints,fD,fE,fF);
133 Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF);
139 void AliTPCpolyTrack::Fit2(Double_t fSumY, Double_t fSumYX, Double_t fSumYX2,
140 Double_t fSumX, Double_t fSumX2, Double_t fSumX3,
141 Double_t fSumX4, Double_t fSumW,
142 Double_t &a, Double_t &b, Double_t &c)
144 //fit of second order
146 fSumW* (fSumX2*fSumX4-fSumX3*fSumX3) -
147 fSumX* (fSumX*fSumX4-fSumX3*fSumX2)+
148 fSumX2* (fSumX*fSumX3-fSumX2*fSumX2);
150 if (TMath::Abs(det)> 0.000000000000001) {
152 (fSumY * (fSumX2*fSumX4-fSumX3*fSumX3)-
153 fSumX *(fSumYX*fSumX4-fSumYX2*fSumX3)+
154 fSumX2*(fSumYX*fSumX3-fSumYX2*fSumX2))/det;
156 (fSumW*(fSumYX*fSumX4-fSumX3*fSumYX2)-
157 fSumY*(fSumX*fSumX4-fSumX3*fSumX2)+
158 fSumX2*(fSumX*fSumYX2-fSumYX*fSumX2))/det;
160 (fSumW*(fSumX2*fSumYX2-fSumYX*fSumX3)-
161 fSumX*(fSumX*fSumYX2-fSumYX*fSumX2)+
162 fSumY*(fSumX*fSumX3-fSumX2*fSumX2))/det;
166 void AliTPCpolyTrack::Fit1(Double_t fSumY, Double_t fSumYX,
167 Double_t fSumX, Double_t fSumX2,
168 Double_t fSumW, Double_t &a, Double_t &b, Double_t &c)
173 Double_t det = fSumW*fSumX2-fSumX*fSumX;
174 if (TMath::Abs(det)> 0.000000000000001) {
175 b = (fSumW*fSumYX-fSumX*fSumY)/det;
176 a = (fSumX2*fSumY-fSumX*fSumYX)/det;
186 void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz)
189 // refit with cut on distortion
192 //first refit to temporary
193 AliTPCpolyTrack track0;
195 for (Int_t i=0;i<fNPoints;i++){
197 GetFitPoint(fX[i],y,z);
198 if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){
199 track0.AddPoint(fX[i],y,z);
203 track0.UpdateParameters();
207 for (Int_t i=0;i<fNPoints;i++){
209 track0.GetFitPoint(fX[i],y,z);
210 if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){
211 track.AddPoint(fX[i],y,z);
215 track.UpdateParameters();
219 void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz, Int_t nfirst, Int_t ny, Int_t nz)
222 // refit with cut on distortion
225 //first refit to temporary
226 AliTPCpolyTrack track0;
228 for (Int_t i=0;i<fNPoints;i++){
230 GetFitPoint(fX[i],y,z);
231 if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){
232 track0.AddPoint(fX[i],y,z);
235 if (track0.GetN()>2){
236 if (track0.GetN()>nfirst)
237 track0.UpdateParameters(ny,nz);
239 track0.UpdateParameters(1,1);
244 for (Int_t i=0;i<fNPoints;i++){
246 track0.GetFitPoint(fX[i],y,z);
247 if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){
248 track.AddPoint(fX[i],y,z);
252 track.UpdateParameters(ny,nz);