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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 | **************************************************************************/ | |
15 | ||
16 | ||
17 | #include "AliTPCpolyTrack.h" | |
18 | #include "TMath.h" | |
19 | ||
20 | ClassImp(AliTPCpolyTrack) | |
21 | ||
22 | ||
23 | AliTPCpolyTrack::AliTPCpolyTrack() | |
24 | { | |
25 | Reset(); | |
26 | } | |
27 | ||
28 | void AliTPCpolyTrack::Reset() | |
29 | { | |
30 | // | |
31 | // reset track | |
32 | fSumX = fSumX2= fSumX3=fSumX4 = fSumY=fSumYX=fSumYX2=fSumZ=fSumZX=fSumZX2=fSumW =0; | |
33 | fNPoints = 0; | |
34 | } | |
35 | ||
36 | void AliTPCpolyTrack::AddPoint(Double_t x, Double_t y, Double_t z,Double_t sy, Double_t sz) | |
37 | { | |
38 | // | |
39 | // | |
40 | if (fNPoints==0){ | |
41 | fMaxX = x; | |
42 | fMinX = x; | |
43 | }else{ | |
44 | if (x>fMaxX) fMaxX=x; | |
45 | if (x<fMinX) fMinX=x; | |
46 | } | |
47 | ||
48 | Double_t x2 = x*x; | |
49 | Double_t w = 2./(sy+sz); | |
50 | fSumW += w; | |
51 | // | |
52 | fSumX += x*w; | |
53 | fSumX2 += x2*w; | |
54 | fSumX3 += x2*x*w; | |
55 | fSumX4 += x2*x2*w; | |
56 | // | |
57 | fSumY +=y*w; | |
58 | fSumYX +=y*x*w; | |
59 | fSumYX2 +=y*x2*w; | |
60 | // | |
61 | fSumZ +=z*w; | |
62 | fSumZX +=z*x*w; | |
63 | fSumZX2 +=z*x2*w; | |
64 | // | |
65 | fX[fNPoints] = x; | |
66 | fY[fNPoints] = y; | |
67 | fZ[fNPoints] = z; | |
68 | fSY[fNPoints] = sy; | |
69 | fSZ[fNPoints] = sz; | |
70 | ||
71 | fNPoints++; | |
72 | ||
73 | } | |
74 | ||
75 | void AliTPCpolyTrack::UpdateParameters() | |
76 | { | |
77 | // | |
78 | // | |
79 | //Update fit parameters | |
80 | if (fNPoints>4){ | |
81 | Fit2(fSumY,fSumYX,fSumYX2,fSumX,fSumX2,fSumX3,fSumX4,fSumW,fA,fB,fC); | |
82 | // Fit2(fSumZ,fSumZX,fSumZX2,fSumX,fSumX2,fSumX3,fSumX4,fNPoints,fD,fE,fF); | |
83 | Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF); | |
84 | } | |
85 | else | |
86 | { | |
87 | Fit1(fSumY,fSumYX,fSumX,fSumX2,fSumW,fA,fB,fC); | |
88 | Fit1(fSumZ,fSumZX,fSumX,fSumX2,fSumW,fD,fE,fF); | |
89 | } | |
90 | } | |
91 | ||
92 | ||
1627d1c4 | 93 | |
94 | void AliTPCpolyTrack::Fit2(Double_t fSumY, Double_t fSumYX, Double_t fSumYX2, | |
95 | Double_t fSumX, Double_t fSumX2, Double_t fSumX3, | |
96 | Double_t fSumX4, Double_t fSumW, | |
97 | Double_t &a, Double_t &b, Double_t &c) | |
98 | { | |
99 | //fit of second order | |
100 | Double_t det = | |
101 | fSumW* (fSumX2*fSumX4-fSumX3*fSumX3) - | |
102 | fSumX* (fSumX*fSumX4-fSumX3*fSumX2)+ | |
103 | fSumX2* (fSumX*fSumX3-fSumX2*fSumX2); | |
104 | ||
105 | if (TMath::Abs(det)> 0.000000000000001) { | |
106 | a = | |
107 | (fSumY * (fSumX2*fSumX4-fSumX3*fSumX3)- | |
108 | fSumX *(fSumYX*fSumX4-fSumYX2*fSumX3)+ | |
109 | fSumX2*(fSumYX*fSumX3-fSumYX2*fSumX2))/det; | |
110 | b= | |
111 | (fSumW*(fSumYX*fSumX4-fSumX3*fSumYX2)- | |
112 | fSumY*(fSumX*fSumX4-fSumX3*fSumX2)+ | |
113 | fSumX2*(fSumX*fSumYX2-fSumYX*fSumX2))/det; | |
114 | c= | |
115 | (fSumW*(fSumX2*fSumYX2-fSumYX*fSumX3)- | |
116 | fSumX*(fSumX*fSumYX2-fSumYX*fSumX2)+ | |
117 | fSumY*(fSumX*fSumX3-fSumX2*fSumX2))/det; | |
118 | } | |
119 | } | |
120 | ||
121 | void AliTPCpolyTrack::Fit1(Double_t fSumY, Double_t fSumYX, | |
122 | Double_t fSumX, Double_t fSumX2, | |
123 | Double_t fSumW, Double_t &a, Double_t &b, Double_t &c) | |
124 | { | |
125 | // | |
126 | // | |
127 | // | |
128 | Double_t det = fSumW*fSumX2-fSumX*fSumX; | |
129 | if (TMath::Abs(det)> 0.000000000000001) { | |
130 | b = (fSumW*fSumYX-fSumX*fSumY)/det; | |
131 | a = (fSumX2*fSumY-fSumX*fSumYX)/det; | |
132 | c = 0; | |
133 | }else{ | |
134 | a =fSumYX/fSumX; | |
135 | b =0; | |
136 | c =0; | |
137 | } | |
138 | ||
139 | } | |
37264142 | 140 | |
141 | void AliTPCpolyTrack::Refit(AliTPCpolyTrack &track, Double_t deltay, Double_t deltaz) | |
142 | { | |
143 | // | |
144 | // refit with cut on distortion | |
145 | // | |
146 | track.Reset(); | |
147 | //first refit to temporary | |
148 | AliTPCpolyTrack track0; | |
149 | track0.Reset; | |
150 | for (Int_t i=0;i<fNPoints;i++){ | |
151 | Double_t y,z; | |
152 | GetFitPoint(fX[i],y,z); | |
153 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
154 | track0.AddPoint(fX[i],y,z); | |
155 | } | |
156 | } | |
157 | if (track0.GetN()>2) | |
158 | track0.UpdateParameters(); | |
159 | else | |
160 | return; | |
161 | // | |
162 | for (Int_t i=0;i<fNPoints;i++){ | |
163 | Double_t y,z; | |
164 | track0.GetFitPoint(fX[i],y,z); | |
165 | if ( (TMath::Abs(y-fY[i])<deltay)&&(TMath::Abs(z-fZ[i])<deltaz)){ | |
166 | track.AddPoint(fX[i],y,z); | |
167 | } | |
168 | } | |
169 | if (track.GetN()>2) | |
170 | track.UpdateParameters(); | |
171 | ||
172 | } | |
173 |