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1627d1c4 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
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 | **************************************************************************/ | |
ae7eb9a4 | 15 | //------------------------------------------------------------------ |
16 | // this class is used for a simple | |
17 | // track fitting using the polynom | |
18 | // bending in both directions are allowed | |
19 | //----------------------------------------------------------------- | |
1627d1c4 | 20 | |
21 | ||
22 | #include "AliTPCpolyTrack.h" | |
23 | #include "TMath.h" | |
24 | ||
25 | ClassImp(AliTPCpolyTrack) | |
26 | ||
27 | ||
28 | AliTPCpolyTrack::AliTPCpolyTrack() | |
29 | { | |
30 | Reset(); | |
31 | } | |
32 | ||
33 | void AliTPCpolyTrack::Reset() | |
34 | { | |
35 | // | |
36 | // reset track | |
37 | fSumX = fSumX2= fSumX3=fSumX4 = fSumY=fSumYX=fSumYX2=fSumZ=fSumZX=fSumZX2=fSumW =0; | |
38 | fNPoints = 0; | |
39 | } | |
40 | ||
41 | void AliTPCpolyTrack::AddPoint(Double_t x, Double_t y, Double_t z,Double_t sy, Double_t sz) | |
42 | { | |
43 | // | |
44 | // | |
45 | if (fNPoints==0){ | |
46 | fMaxX = x; | |
47 | fMinX = x; | |
48 | }else{ | |
49 | if (x>fMaxX) fMaxX=x; | |
50 | if (x<fMinX) fMinX=x; | |
51 | } | |
52 | ||
53 | Double_t x2 = x*x; | |
54 | Double_t w = 2./(sy+sz); | |
55 | fSumW += w; | |
56 | // | |
57 | fSumX += x*w; | |
58 | fSumX2 += x2*w; | |
59 | fSumX3 += x2*x*w; | |
60 | fSumX4 += x2*x2*w; | |
61 | // | |
62 | fSumY +=y*w; | |
63 | fSumYX +=y*x*w; | |
64 | fSumYX2 +=y*x2*w; | |
65 | // | |
66 | fSumZ +=z*w; | |
67 | fSumZX +=z*x*w; | |
68 | fSumZX2 +=z*x2*w; | |
69 | // | |
70 | fX[fNPoints] = x; | |
71 | fY[fNPoints] = y; | |
72 | fZ[fNPoints] = z; | |
73 | fSY[fNPoints] = sy; | |
74 | fSZ[fNPoints] = sz; | |
75 | ||
76 | fNPoints++; | |
77 | ||
78 | } | |
79 | ||
80 | void AliTPCpolyTrack::UpdateParameters() | |
81 | { | |
82 | // | |
83 | // | |
84 | //Update fit parameters | |
85 | if (fNPoints>4){ | |
86 | Fit2(fSumY,fSumYX,fSumYX2,fSumX,fSumX2,fSumX3,fSumX4,fSumW,fA,fB,fC); | |
87 | // Fit2(fSumZ,fSumZX,fSumZX2,fSumX,fSumX2,fSumX3,fSumX4,fNPoints,fD,fE,fF); | |
88 | Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF); | |
89 | } | |
90 | else | |
91 | { | |
92 | Fit1(fSumY,fSumYX,fSumX,fSumX2,fSumW,fA,fB,fC); | |
93 | Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF); | |
94 | } | |
95 | } | |
96 | ||
0909b376 | 97 | void AliTPCpolyTrack::UpdateParameters(Int_t ny, Int_t nz) |
98 | { | |
99 | // | |
100 | // | |
101 | //Update fit parameters | |
102 | if (ny>1){ | |
103 | Fit2(fSumY,fSumYX,fSumYX2,fSumX,fSumX2,fSumX3,fSumX4,fSumW,fA,fB,fC); | |
104 | } | |
105 | else{ | |
106 | Fit1(fSumY,fSumYX,fSumX,fSumX2,fSumW,fA,fB,fC); | |
107 | } | |
108 | if (nz>1){ | |
109 | Fit2(fSumZ,fSumZX,fSumZX2,fSumX,fSumX2,fSumX3,fSumX4,fNPoints,fD,fE,fF); | |
110 | } | |
111 | else{ | |
112 | Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF); | |
113 | } | |
114 | } | |
115 | ||
1627d1c4 | 116 | |
1627d1c4 | 117 | |
118 | void AliTPCpolyTrack::Fit2(Double_t fSumY, Double_t fSumYX, Double_t fSumYX2, | |
119 | Double_t fSumX, Double_t fSumX2, Double_t fSumX3, | |
120 | Double_t fSumX4, Double_t fSumW, | |
121 | Double_t &a, Double_t &b, Double_t &c) | |
122 | { | |
123 | //fit of second order | |
124 | Double_t det = | |
125 | fSumW* (fSumX2*fSumX4-fSumX3*fSumX3) - | |
126 | fSumX* (fSumX*fSumX4-fSumX3*fSumX2)+ | |
127 | fSumX2* (fSumX*fSumX3-fSumX2*fSumX2); | |
128 | ||
129 | if (TMath::Abs(det)> 0.000000000000001) { | |
130 | a = | |
131 | (fSumY * (fSumX2*fSumX4-fSumX3*fSumX3)- | |
132 | fSumX *(fSumYX*fSumX4-fSumYX2*fSumX3)+ | |
133 | fSumX2*(fSumYX*fSumX3-fSumYX2*fSumX2))/det; | |
134 | b= | |
135 | (fSumW*(fSumYX*fSumX4-fSumX3*fSumYX2)- | |
136 | fSumY*(fSumX*fSumX4-fSumX3*fSumX2)+ | |
137 | fSumX2*(fSumX*fSumYX2-fSumYX*fSumX2))/det; | |
138 | c= | |
139 | (fSumW*(fSumX2*fSumYX2-fSumYX*fSumX3)- | |
140 | fSumX*(fSumX*fSumYX2-fSumYX*fSumX2)+ | |
141 | fSumY*(fSumX*fSumX3-fSumX2*fSumX2))/det; | |
142 | } | |
143 | } | |
144 | ||
145 | void AliTPCpolyTrack::Fit1(Double_t fSumY, Double_t fSumYX, | |
146 | Double_t fSumX, Double_t fSumX2, | |
147 | Double_t fSumW, Double_t &a, Double_t &b, Double_t &c) | |
148 | { | |
149 | // | |
150 | // | |
151 | // | |
152 | Double_t det = fSumW*fSumX2-fSumX*fSumX; | |
153 | if (TMath::Abs(det)> 0.000000000000001) { | |
154 | b = (fSumW*fSumYX-fSumX*fSumY)/det; | |
155 | a = (fSumX2*fSumY-fSumX*fSumYX)/det; | |
156 | c = 0; | |
157 | }else{ | |
158 | a =fSumYX/fSumX; | |
159 | b =0; | |
160 | c =0; | |
161 | } | |
162 | ||
163 | } | |
37264142 | 164 | |
165 | void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz) | |
166 | { | |
167 | // | |
168 | // refit with cut on distortion | |
169 | // | |
170 | track.Reset(); | |
171 | //first refit to temporary | |
172 | AliTPCpolyTrack track0; | |
330d3170 | 173 | track0.Reset(); |
37264142 | 174 | for (Int_t i=0;i<fNPoints;i++){ |
175 | Double_t y,z; | |
176 | GetFitPoint(fX[i],y,z); | |
177 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
178 | track0.AddPoint(fX[i],y,z); | |
179 | } | |
180 | } | |
181 | if (track0.GetN()>2) | |
182 | track0.UpdateParameters(); | |
183 | else | |
184 | return; | |
185 | // | |
186 | for (Int_t i=0;i<fNPoints;i++){ | |
187 | Double_t y,z; | |
188 | track0.GetFitPoint(fX[i],y,z); | |
189 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
190 | track.AddPoint(fX[i],y,z); | |
191 | } | |
192 | } | |
193 | if (track.GetN()>2) | |
194 | track.UpdateParameters(); | |
195 | ||
196 | } | |
197 | ||
0909b376 | 198 | void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz, Int_t nfirst, Int_t ny, Int_t nz) |
199 | { | |
200 | // | |
201 | // refit with cut on distortion | |
202 | // | |
203 | track.Reset(); | |
204 | //first refit to temporary | |
205 | AliTPCpolyTrack track0; | |
206 | track0.Reset(); | |
207 | for (Int_t i=0;i<fNPoints;i++){ | |
208 | Double_t y,z; | |
209 | GetFitPoint(fX[i],y,z); | |
210 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
211 | track0.AddPoint(fX[i],y,z); | |
212 | } | |
213 | } | |
214 | if (track0.GetN()>2){ | |
215 | if (track0.GetN()>nfirst) | |
216 | track0.UpdateParameters(ny,nz); | |
217 | else | |
218 | track0.UpdateParameters(1,1); | |
219 | } | |
220 | else | |
221 | return; | |
222 | // | |
223 | for (Int_t i=0;i<fNPoints;i++){ | |
224 | Double_t y,z; | |
225 | track0.GetFitPoint(fX[i],y,z); | |
226 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
227 | track.AddPoint(fX[i],y,z); | |
228 | } | |
229 | } | |
230 | if (track.GetN()>2) | |
231 | track.UpdateParameters(ny,nz); | |
232 | ||
233 | } | |
234 |