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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() | |
179c6296 | 29 | :TObject(), |
30 | fA(0), | |
31 | fB(0), | |
32 | fC(0), | |
33 | fD(0), | |
34 | fE(0), | |
35 | fF(0), | |
36 | fMaxX(0), | |
37 | fMinX(0), | |
38 | fSumW(0), | |
39 | fSumX(0), | |
40 | fSumX2(0), | |
41 | fSumX3(0), | |
42 | fSumX4(0), | |
43 | fSumY(0), | |
44 | fSumYX(0), | |
45 | fSumYX2(0), | |
46 | fSumZ(0), | |
47 | fSumZX(0), | |
48 | fSumZX2(0), | |
49 | fNPoints(0) | |
1627d1c4 | 50 | { |
51 | Reset(); | |
712976a6 | 52 | // |
53 | for(Int_t i=0;i<200;i++){ | |
54 | fX[i]=0.; | |
55 | fY[i]=0.; | |
56 | fSY[i]=0.; | |
57 | fZ[i]=0.; | |
58 | fSZ[i]=0.; | |
59 | } | |
1627d1c4 | 60 | } |
61 | ||
62 | void AliTPCpolyTrack::Reset() | |
63 | { | |
64 | // | |
65 | // reset track | |
66 | fSumX = fSumX2= fSumX3=fSumX4 = fSumY=fSumYX=fSumYX2=fSumZ=fSumZX=fSumZX2=fSumW =0; | |
67 | fNPoints = 0; | |
68 | } | |
69 | ||
70 | void AliTPCpolyTrack::AddPoint(Double_t x, Double_t y, Double_t z,Double_t sy, Double_t sz) | |
71 | { | |
72 | // | |
73 | // | |
74 | if (fNPoints==0){ | |
75 | fMaxX = x; | |
76 | fMinX = x; | |
77 | }else{ | |
78 | if (x>fMaxX) fMaxX=x; | |
79 | if (x<fMinX) fMinX=x; | |
80 | } | |
81 | ||
82 | Double_t x2 = x*x; | |
83 | Double_t w = 2./(sy+sz); | |
84 | fSumW += w; | |
85 | // | |
86 | fSumX += x*w; | |
87 | fSumX2 += x2*w; | |
88 | fSumX3 += x2*x*w; | |
89 | fSumX4 += x2*x2*w; | |
90 | // | |
91 | fSumY +=y*w; | |
92 | fSumYX +=y*x*w; | |
93 | fSumYX2 +=y*x2*w; | |
94 | // | |
95 | fSumZ +=z*w; | |
96 | fSumZX +=z*x*w; | |
97 | fSumZX2 +=z*x2*w; | |
98 | // | |
99 | fX[fNPoints] = x; | |
100 | fY[fNPoints] = y; | |
101 | fZ[fNPoints] = z; | |
102 | fSY[fNPoints] = sy; | |
103 | fSZ[fNPoints] = sz; | |
104 | ||
105 | fNPoints++; | |
106 | ||
107 | } | |
108 | ||
109 | void AliTPCpolyTrack::UpdateParameters() | |
110 | { | |
111 | // | |
112 | // | |
113 | //Update fit parameters | |
114 | if (fNPoints>4){ | |
abb58ea3 | 115 | Fit2(fA,fB,fC); |
1627d1c4 | 116 | // Fit2(fSumZ,fSumZX,fSumZX2,fSumX,fSumX2,fSumX3,fSumX4,fNPoints,fD,fE,fF); |
abb58ea3 | 117 | Fit1(fD,fE,fF); |
1627d1c4 | 118 | } |
119 | else | |
120 | { | |
abb58ea3 | 121 | Fit1(fA,fB,fC); |
122 | Fit1(fD,fE,fF); | |
1627d1c4 | 123 | } |
124 | } | |
125 | ||
0909b376 | 126 | void AliTPCpolyTrack::UpdateParameters(Int_t ny, Int_t nz) |
127 | { | |
128 | // | |
129 | // | |
130 | //Update fit parameters | |
131 | if (ny>1){ | |
abb58ea3 | 132 | Fit2(fA,fB,fC); |
0909b376 | 133 | } |
134 | else{ | |
abb58ea3 | 135 | Fit1(fA,fB,fC); |
0909b376 | 136 | } |
137 | if (nz>1){ | |
abb58ea3 | 138 | Fit2(fD,fE,fF); |
0909b376 | 139 | } |
140 | else{ | |
abb58ea3 | 141 | Fit1(fD,fE,fF); |
0909b376 | 142 | } |
143 | } | |
144 | ||
1627d1c4 | 145 | |
1627d1c4 | 146 | |
abb58ea3 | 147 | void AliTPCpolyTrack::Fit2( |
1627d1c4 | 148 | Double_t &a, Double_t &b, Double_t &c) |
149 | { | |
150 | //fit of second order | |
151 | Double_t det = | |
152 | fSumW* (fSumX2*fSumX4-fSumX3*fSumX3) - | |
153 | fSumX* (fSumX*fSumX4-fSumX3*fSumX2)+ | |
154 | fSumX2* (fSumX*fSumX3-fSumX2*fSumX2); | |
155 | ||
156 | if (TMath::Abs(det)> 0.000000000000001) { | |
157 | a = | |
158 | (fSumY * (fSumX2*fSumX4-fSumX3*fSumX3)- | |
159 | fSumX *(fSumYX*fSumX4-fSumYX2*fSumX3)+ | |
160 | fSumX2*(fSumYX*fSumX3-fSumYX2*fSumX2))/det; | |
161 | b= | |
162 | (fSumW*(fSumYX*fSumX4-fSumX3*fSumYX2)- | |
163 | fSumY*(fSumX*fSumX4-fSumX3*fSumX2)+ | |
164 | fSumX2*(fSumX*fSumYX2-fSumYX*fSumX2))/det; | |
165 | c= | |
166 | (fSumW*(fSumX2*fSumYX2-fSumYX*fSumX3)- | |
167 | fSumX*(fSumX*fSumYX2-fSumYX*fSumX2)+ | |
168 | fSumY*(fSumX*fSumX3-fSumX2*fSumX2))/det; | |
169 | } | |
170 | } | |
171 | ||
abb58ea3 | 172 | void AliTPCpolyTrack::Fit1( Double_t &a, Double_t &b, Double_t &c) |
1627d1c4 | 173 | { |
174 | // | |
175 | // | |
176 | // | |
177 | Double_t det = fSumW*fSumX2-fSumX*fSumX; | |
178 | if (TMath::Abs(det)> 0.000000000000001) { | |
179 | b = (fSumW*fSumYX-fSumX*fSumY)/det; | |
180 | a = (fSumX2*fSumY-fSumX*fSumYX)/det; | |
181 | c = 0; | |
182 | }else{ | |
183 | a =fSumYX/fSumX; | |
184 | b =0; | |
185 | c =0; | |
186 | } | |
187 | ||
188 | } | |
37264142 | 189 | |
190 | void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz) | |
191 | { | |
192 | // | |
193 | // refit with cut on distortion | |
194 | // | |
195 | track.Reset(); | |
196 | //first refit to temporary | |
197 | AliTPCpolyTrack track0; | |
330d3170 | 198 | track0.Reset(); |
37264142 | 199 | for (Int_t i=0;i<fNPoints;i++){ |
200 | Double_t y,z; | |
201 | GetFitPoint(fX[i],y,z); | |
202 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
203 | track0.AddPoint(fX[i],y,z); | |
204 | } | |
205 | } | |
206 | if (track0.GetN()>2) | |
207 | track0.UpdateParameters(); | |
208 | else | |
209 | return; | |
210 | // | |
211 | for (Int_t i=0;i<fNPoints;i++){ | |
212 | Double_t y,z; | |
213 | track0.GetFitPoint(fX[i],y,z); | |
214 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
215 | track.AddPoint(fX[i],y,z); | |
216 | } | |
217 | } | |
218 | if (track.GetN()>2) | |
219 | track.UpdateParameters(); | |
220 | ||
221 | } | |
222 | ||
0909b376 | 223 | void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz, Int_t nfirst, Int_t ny, Int_t nz) |
224 | { | |
225 | // | |
226 | // refit with cut on distortion | |
227 | // | |
228 | track.Reset(); | |
229 | //first refit to temporary | |
230 | AliTPCpolyTrack track0; | |
231 | track0.Reset(); | |
232 | for (Int_t i=0;i<fNPoints;i++){ | |
233 | Double_t y,z; | |
234 | GetFitPoint(fX[i],y,z); | |
235 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
236 | track0.AddPoint(fX[i],y,z); | |
237 | } | |
238 | } | |
239 | if (track0.GetN()>2){ | |
240 | if (track0.GetN()>nfirst) | |
241 | track0.UpdateParameters(ny,nz); | |
242 | else | |
243 | track0.UpdateParameters(1,1); | |
244 | } | |
245 | else | |
246 | return; | |
247 | // | |
248 | for (Int_t i=0;i<fNPoints;i++){ | |
249 | Double_t y,z; | |
250 | track0.GetFitPoint(fX[i],y,z); | |
251 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
252 | track.AddPoint(fX[i],y,z); | |
253 | } | |
254 | } | |
255 | if (track.GetN()>2) | |
256 | track.UpdateParameters(ny,nz); | |
257 | ||
258 | } | |
259 |