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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 | // Implementation of the ITS track class |
18 | // |
19 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch |
a9a2d814 |
20 | // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch |
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21 | //------------------------------------------------------------------------- |
22 | |
23 | #include <TMatrixD.h> |
24 | |
25 | #include <TMath.h> |
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26 | #include <Riostream.h> |
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27 | |
28 | #include "AliCluster.h" |
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29 | #include "AliTPCtrack.h" |
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30 | #include "AliITStrackV2.h" |
31 | |
32 | ClassImp(AliITStrackV2) |
33 | |
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34 | const Int_t kWARN=5; |
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35 | |
36 | //____________________________________________________________________________ |
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37 | AliITStrackV2::AliITStrackV2(const AliTPCtrack& t) throw (const Char_t *) : |
38 | AliKalmanTrack(t) { |
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39 | //------------------------------------------------------------------ |
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40 | //Conversion TPC track -> ITS track |
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41 | //------------------------------------------------------------------ |
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42 | SetChi2(0.); |
43 | SetNumberOfClusters(0); |
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44 | |
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45 | fdEdx = t.GetdEdx(); |
46 | SetMass(t.GetMass()); |
47 | |
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48 | fAlpha = t.GetAlpha(); |
49 | if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi(); |
50 | else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi(); |
51 | |
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52 | //Conversion of the track parameters |
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53 | Double_t x,p[5]; t.GetExternalParameters(x,p); |
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54 | fX=x; x=GetConvConst(); |
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55 | fP0=p[0]; |
56 | fP1=p[1]; |
57 | fP2=p[2]; |
58 | fP3=p[3]; |
59 | fP4=p[4]/x; |
60 | |
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61 | //Conversion of the covariance matrix |
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62 | Double_t c[15]; t.GetExternalCovariance(c); |
63 | |
64 | fC00=c[0 ]; |
65 | fC10=c[1 ]; fC11=c[2 ]; |
66 | fC20=c[3 ]; fC21=c[4 ]; fC22=c[5 ]; |
67 | fC30=c[6 ]; fC31=c[7 ]; fC32=c[8 ]; fC33=c[9 ]; |
68 | fC40=c[10]/x; fC41=c[11]/x; fC42=c[12]/x; fC43=c[13]/x; fC44=c[14]/x/x; |
69 | |
70 | if (!Invariant()) throw "AliITStrackV2: conversion failed !\n"; |
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71 | |
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72 | } |
73 | |
74 | //____________________________________________________________________________ |
75 | AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) { |
76 | //------------------------------------------------------------------ |
77 | //Copy constructor |
78 | //------------------------------------------------------------------ |
79 | fX=t.fX; |
80 | fAlpha=t.fAlpha; |
81 | fdEdx=t.fdEdx; |
82 | |
83 | fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4; |
84 | |
85 | fC00=t.fC00; |
86 | fC10=t.fC10; fC11=t.fC11; |
87 | fC20=t.fC20; fC21=t.fC21; fC22=t.fC22; |
88 | fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33; |
89 | fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44; |
90 | |
91 | Int_t n=GetNumberOfClusters(); |
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92 | for (Int_t i=0; i<n; i++) { |
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93 | fIndex[i]=t.fIndex[i]; |
94 | if (i<4) fdEdxSample[i]=t.fdEdxSample[i]; |
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95 | } |
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96 | } |
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97 | |
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98 | //_____________________________________________________________________________ |
99 | Int_t AliITStrackV2::Compare(const TObject *o) const { |
100 | //----------------------------------------------------------------- |
101 | // This function compares tracks according to the their curvature |
102 | //----------------------------------------------------------------- |
7f6ddf58 |
103 | AliITStrackV2 *t=(AliITStrackV2*)o; |
a9a2d814 |
104 | //Double_t co=TMath::Abs(t->Get1Pt()); |
105 | //Double_t c =TMath::Abs(Get1Pt()); |
106 | Double_t co=t->GetSigmaY2()*t->GetSigmaZ2(); |
107 | Double_t c =GetSigmaY2()*GetSigmaZ2(); |
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108 | if (c>co) return 1; |
109 | else if (c<co) return -1; |
110 | return 0; |
111 | } |
112 | |
113 | //_____________________________________________________________________________ |
114 | void AliITStrackV2::GetExternalCovariance(Double_t cc[15]) const { |
115 | //------------------------------------------------------------------------- |
116 | // This function returns an external representation of the covriance matrix. |
117 | // (See comments in AliTPCtrack.h about external track representation) |
118 | //------------------------------------------------------------------------- |
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119 | Double_t a=GetConvConst(); |
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120 | |
121 | cc[0 ]=fC00; |
122 | cc[1 ]=fC10; cc[2 ]=fC11; |
123 | cc[3 ]=fC20; cc[4 ]=fC21; cc[5 ]=fC22; |
124 | cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=fC32; cc[9 ]=fC33; |
125 | cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=fC42*a; cc[13]=fC43*a; cc[14]=fC44*a*a; |
126 | } |
127 | |
128 | //____________________________________________________________________________ |
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129 | Int_t AliITStrackV2::PropagateToVertex(Double_t d,Double_t x0) { |
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130 | //------------------------------------------------------------------ |
131 | //This function propagates a track to the minimal distance from the origin |
132 | //------------------------------------------------------------------ |
133 | Double_t xv=fP2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2)); //linear approxim. |
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134 | PropagateTo(xv,d,x0); |
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135 | return 0; |
136 | } |
137 | |
138 | //____________________________________________________________________________ |
139 | Int_t AliITStrackV2:: |
140 | GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const { |
141 | //------------------------------------------------------------------ |
142 | //This function returns a track position in the global system |
143 | //------------------------------------------------------------------ |
144 | Double_t dx=xk-fX; |
145 | Double_t f1=fP2, f2=f1 + fP4*dx; |
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146 | if (TMath::Abs(f2) >= 0.9999) { |
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147 | Int_t n=GetNumberOfClusters(); |
148 | if (n>kWARN) |
149 | cerr<<n<<" AliITStrackV2::GetGlobalXYZat: Propagation failed !\n"; |
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150 | return 0; |
151 | } |
152 | |
153 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); |
154 | |
155 | Double_t yk = fP0 + dx*(f1+f2)/(r1+r2); |
156 | Double_t zk = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; |
157 | |
158 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); |
159 | x = xk*cs - yk*sn; |
160 | y = xk*sn + yk*cs; |
161 | z = zk; |
162 | |
163 | return 1; |
164 | } |
165 | |
166 | //_____________________________________________________________________________ |
167 | Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const |
168 | { |
169 | //----------------------------------------------------------------- |
170 | // This function calculates a predicted chi2 increment. |
171 | //----------------------------------------------------------------- |
172 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); |
173 | r00+=fC00; r01+=fC10; r11+=fC11; |
174 | |
175 | Double_t det=r00*r11 - r01*r01; |
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176 | if (TMath::Abs(det) < 1.e-30) { |
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177 | Int_t n=GetNumberOfClusters(); |
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178 | if (n>kWARN) |
179 | cerr<<n<<" AliKalmanTrack::GetPredictedChi2: Singular matrix !\n"; |
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180 | return 1e10; |
181 | } |
182 | Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01; |
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183 | |
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184 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; |
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185 | |
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186 | return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det; |
187 | } |
188 | |
189 | //_____________________________________________________________________________ |
190 | Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c,Double_t *m, |
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191 | Double_t x0) const { |
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192 | //----------------------------------------------------------------- |
193 | // This function calculates a chi2 increment with a vertex contraint |
194 | //----------------------------------------------------------------- |
195 | TVectorD x(5); x(0)=fP0; x(1)=fP1; x(2)=fP2; x(3)=fP3; x(4)=fP4; |
196 | TMatrixD C(5,5); |
197 | C(0,0)=fC00; |
198 | C(1,0)=fC10; C(1,1)=fC11; |
199 | C(2,0)=fC20; C(2,1)=fC21; C(2,2)=fC22; |
200 | C(3,0)=fC30; C(3,1)=fC31; C(3,2)=fC32; C(3,3)=fC33; |
201 | C(4,0)=fC40; C(4,1)=fC41; C(4,2)=fC42; C(4,3)=fC43; C(4,4)=fC44; |
202 | |
203 | C(0,1)=C(1,0); |
204 | C(0,2)=C(2,0); C(1,2)=C(2,1); |
205 | C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2); |
206 | C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3); |
207 | |
208 | TMatrixD H(4,5); H.UnitMatrix(); |
209 | Double_t dy=(c->GetY() - m[0]), dz=(c->GetZ() - m[1]); |
210 | |
211 | Double_t dr=TMath::Sqrt(fX*fX + dy*dy); |
212 | Double_t r =TMath::Sqrt(4/dr/dr - fP4*fP4); |
213 | Double_t sn=0.5*(fP4*fX + dy*r); |
214 | Double_t tg=0.5*fP4*dz/TMath::ASin(0.5*fP4*dr); |
215 | TVectorD mm(4); |
216 | mm(0)=m[0]=c->GetY(); mm(1)=m[1]=c->GetZ(); mm(2)=m[2]=sn; mm(3)=m[3]=tg; |
217 | |
218 | Double_t v22=0.,v33=0.; |
219 | //x0=0.; |
220 | if (x0!=0.) { |
221 | Double_t pp2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); |
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222 | Double_t beta2=pp2/(pp2 + GetMass()*GetMass()); |
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223 | x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp())); |
224 | Double_t theta2=14.1*14.1/(beta2*pp2*1e6)*x0; |
225 | v22 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl()); |
226 | v33 = theta2*(1.+ GetTgl()*GetTgl())*(1. + GetTgl()*GetTgl()); |
227 | } |
228 | Double_t sy2=c->GetSigmaY2(), sz2=c->GetSigmaZ2(); |
229 | v22+=kSigmaYV*kSigmaYV/dr/dr; |
230 | v22+=sy2/dr/dr; |
231 | Double_t v20=sy2/dr; |
232 | |
233 | v33+=kSigmaZV*kSigmaZV/dr/dr; |
234 | v33+=sz2/dr/dr; |
235 | Double_t v31=sz2/dr; |
236 | |
237 | TMatrixD V(4,4); |
238 | V(0,0)=m[4 ]=sy2; V(0,1)=m[5 ]=0.; V(0,2)=m[6 ]=v20; V(0,3)=m[7 ]=0.; |
239 | V(1,0)=m[8 ]=0.; V(1,1)=m[9 ]=sz2; V(1,2)=m[10]=0.; V(1,3)=m[11]=v31; |
240 | V(2,0)=m[12]=v20; V(2,1)=m[13]=0.; V(2,2)=m[14]=v22; V(2,3)=m[15]=0.; |
241 | V(3,0)=m[16]=0.; V(3,1)=m[17]=v31; V(3,2)=m[18]=0.; V(3,3)=m[19]=v33; |
242 | |
243 | TVectorD res=x; res*=H; res-=mm; //res*=-1; |
244 | TMatrixD tmp(H,TMatrixD::kMult,C); |
245 | TMatrixD R(tmp,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed,H)); R+=V; |
246 | |
247 | Double_t det=R.Determinant(); |
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248 | if (TMath::Abs(det) < 1.e-30) { |
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249 | Int_t n=GetNumberOfClusters(); |
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250 | if (n>kWARN) |
251 | cerr<<n<<" AliITStrackV2::GetPredictedChi2: Singular matrix !\n"; |
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252 | return 1e10; |
253 | } |
254 | |
255 | R.Invert(); |
256 | |
257 | TVectorD rs=res; |
258 | res*=R; |
259 | return rs*res; |
260 | } |
261 | |
262 | //____________________________________________________________________________ |
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263 | Int_t AliITStrackV2::CorrectForMaterial(Double_t d, Double_t x0) { |
264 | //------------------------------------------------------------------ |
265 | //This function corrects the track parameters for crossed material |
266 | //------------------------------------------------------------------ |
267 | Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); |
268 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); |
269 | d*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2)); |
270 | |
271 | //Multiple scattering****************** |
272 | if (d!=0) { |
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273 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d); |
274 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33; |
a9a2d814 |
275 | fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3); |
276 | fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3); |
277 | fC43 += theta2*fP3*fP4*(1. + fP3*fP3); |
278 | fC44 += theta2*fP3*fP4*fP3*fP4; |
279 | } |
280 | |
281 | //Energy losses************************ |
282 | if (x0!=0.) { |
283 | d*=x0; |
284 | Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d; |
285 | fP4*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE); |
286 | } |
287 | |
288 | if (!Invariant()) return 0; |
289 | |
290 | return 1; |
291 | } |
292 | |
293 | //____________________________________________________________________________ |
294 | Int_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) { |
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295 | //------------------------------------------------------------------ |
296 | //This function propagates a track |
297 | //------------------------------------------------------------------ |
298 | Double_t x1=fX, x2=xk, dx=x2-x1; |
299 | Double_t f1=fP2, f2=f1 + fP4*dx; |
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300 | if (TMath::Abs(f2) >= 0.9999) { |
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301 | Int_t n=GetNumberOfClusters(); |
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302 | if (n>kWARN) |
303 | cerr<<n<<" AliITStrackV2::PropagateTo: Propagation failed !\n"; |
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304 | return 0; |
305 | } |
306 | |
307 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); |
308 | |
309 | fP0 += dx*(f1+f2)/(r1+r2); |
310 | fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; |
311 | fP2 += dx*fP4; |
312 | |
313 | //f = F - 1 |
314 | |
315 | Double_t f02= dx/(r1*r1*r1); |
316 | Double_t f04=0.5*dx*dx/(r1*r1*r1); |
317 | Double_t f12= dx*fP3*f1/(r1*r1*r1); |
318 | Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1); |
319 | Double_t f13= dx/r1; |
320 | Double_t f24= dx; |
321 | |
322 | //b = C*ft |
323 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; |
324 | Double_t b02=f24*fC40; |
325 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; |
326 | Double_t b12=f24*fC41; |
327 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; |
328 | Double_t b22=f24*fC42; |
329 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; |
330 | Double_t b42=f24*fC44; |
331 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; |
332 | Double_t b32=f24*fC43; |
333 | |
334 | //a = f*b = f*C*ft |
335 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42; |
336 | Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32; |
337 | Double_t a22=f24*b42; |
338 | |
339 | //F*C*Ft = C + (b + bt + a) |
340 | fC00 += b00 + b00 + a00; |
341 | fC10 += b10 + b01 + a01; |
342 | fC20 += b20 + b02 + a02; |
343 | fC30 += b30; |
344 | fC40 += b40; |
345 | fC11 += b11 + b11 + a11; |
346 | fC21 += b21 + b12 + a12; |
347 | fC31 += b31; |
348 | fC41 += b41; |
349 | fC22 += b22 + b22 + a22; |
350 | fC32 += b32; |
351 | fC42 += b42; |
352 | |
353 | fX=x2; |
354 | |
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355 | if (!CorrectForMaterial(d,x0)) return 0; |
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356 | |
357 | return 1; |
358 | } |
359 | |
360 | //____________________________________________________________________________ |
361 | Int_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, UInt_t index) { |
362 | //------------------------------------------------------------------ |
363 | //This function updates track parameters |
364 | //------------------------------------------------------------------ |
365 | Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4; |
366 | Double_t c00=fC00; |
367 | Double_t c10=fC10, c11=fC11; |
368 | Double_t c20=fC20, c21=fC21, c22=fC22; |
369 | Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33; |
370 | Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44; |
371 | |
372 | |
373 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); |
374 | r00+=fC00; r01+=fC10; r11+=fC11; |
375 | Double_t det=r00*r11 - r01*r01; |
376 | Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det; |
377 | |
378 | Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11; |
379 | Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11; |
380 | Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11; |
381 | Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11; |
382 | Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11; |
383 | |
384 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; |
385 | Double_t sf=fP2 + k20*dy + k21*dz; |
7f6ddf58 |
386 | |
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387 | fP0 += k00*dy + k01*dz; |
388 | fP1 += k10*dy + k11*dz; |
389 | fP2 = sf; |
390 | fP3 += k30*dy + k31*dz; |
391 | fP4 += k40*dy + k41*dz; |
392 | |
393 | Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40; |
394 | Double_t c12=fC21, c13=fC31, c14=fC41; |
395 | |
396 | fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11; |
397 | fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13; |
398 | fC40-=k00*c04+k01*c14; |
399 | |
400 | fC11-=k10*c01+k11*fC11; |
401 | fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13; |
402 | fC41-=k10*c04+k11*c14; |
403 | |
404 | fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13; |
405 | fC42-=k20*c04+k21*c14; |
406 | |
407 | fC33-=k30*c03+k31*c13; |
408 | fC43-=k30*c04+k31*c14; |
409 | |
410 | fC44-=k40*c04+k41*c14; |
411 | |
412 | if (!Invariant()) { |
413 | fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4; |
414 | fC00=c00; |
415 | fC10=c10; fC11=c11; |
416 | fC20=c20; fC21=c21; fC22=c22; |
417 | fC30=c30; fC31=c31; fC32=c32; fC33=c33; |
418 | fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44; |
419 | return 0; |
420 | } |
421 | |
422 | Int_t n=GetNumberOfClusters(); |
423 | fIndex[n]=index; |
424 | SetNumberOfClusters(n+1); |
425 | SetChi2(GetChi2()+chi2); |
426 | |
427 | return 1; |
428 | } |
429 | |
006b5f7f |
430 | Int_t AliITStrackV2::Invariant() const { |
431 | //------------------------------------------------------------------ |
432 | // This function is for debugging purpose only |
433 | //------------------------------------------------------------------ |
7f6ddf58 |
434 | Int_t n=GetNumberOfClusters(); |
435 | |
a9a2d814 |
436 | if (TMath::Abs(fP2)>=0.9999){ |
437 | if (n>kWARN) cout<<"AliITStrackV2::Invariant : fP2="<<fP2<<endl; |
438 | return 0; |
439 | } |
440 | if (fC00<=0 || fC00>9.) { |
441 | if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC00="<<fC00<<endl; |
442 | return 0; |
443 | } |
444 | if (fC11<=0 || fC11>9.) { |
445 | if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC11="<<fC11<<endl; |
446 | return 0; |
447 | } |
448 | if (fC22<=0 || fC22>1.) { |
449 | if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC22="<<fC22<<endl; |
450 | return 0; |
451 | } |
452 | if (fC33<=0 || fC33>1.) { |
453 | if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC33="<<fC33<<endl; |
454 | return 0; |
455 | } |
456 | if (fC44<=0 || fC44>6e-5) { |
457 | if (n>kWARN) cout<<"AliITStrackV2::Invariant : fC44="<<fC44<<endl; |
458 | return 0; |
14825d5a |
459 | } |
14825d5a |
460 | return 1; |
006b5f7f |
461 | } |
462 | |
463 | //____________________________________________________________________________ |
a9a2d814 |
464 | Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) { |
006b5f7f |
465 | //------------------------------------------------------------------ |
466 | //This function propagates a track |
467 | //------------------------------------------------------------------ |
33329428 |
468 | Double_t alpha=fAlpha, x=fX; |
006b5f7f |
469 | Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4; |
470 | Double_t c00=fC00; |
471 | Double_t c10=fC10, c11=fC11; |
472 | Double_t c20=fC20, c21=fC21, c22=fC22; |
473 | Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33; |
474 | Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44; |
475 | |
33329428 |
476 | if (alp < -TMath::Pi()) alp += 2*TMath::Pi(); |
477 | else if (alp >= TMath::Pi()) alp -= 2*TMath::Pi(); |
478 | Double_t ca=TMath::Cos(alp-fAlpha), sa=TMath::Sin(alp-fAlpha); |
479 | Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2); |
006b5f7f |
480 | |
33329428 |
481 | TMatrixD *T=0; |
482 | // **** rotation ********************** |
483 | { |
006b5f7f |
484 | fAlpha = alp; |
33329428 |
485 | fX = x*ca + p0*sa; |
486 | fP0= -x*sa + p0*ca; |
487 | fP2= sf*ca - cf*sa; |
488 | |
489 | TMatrixD C(5,5); |
490 | C(0,0)=c00; |
491 | C(1,0)=c10; C(1,1)=c11; |
492 | C(2,0)=c20; C(2,1)=c21; C(2,2)=c22; |
493 | C(3,0)=c30; C(3,1)=c31; C(3,2)=c32; C(3,3)=c33; |
494 | C(4,0)=c40; C(4,1)=c41; C(4,2)=c42; C(4,3)=c43; C(4,4)=c44; |
495 | C(0,1)=C(1,0); |
496 | C(0,2)=C(2,0); C(1,2)=C(2,1); |
497 | C(0,3)=C(3,0); C(1,3)=C(3,1); C(2,3)=C(3,2); |
498 | C(0,4)=C(4,0); C(1,4)=C(4,1); C(2,4)=C(4,2); C(3,4)=C(4,3); |
006b5f7f |
499 | |
33329428 |
500 | TMatrixD F(6,5); |
501 | F(0,0)=sa; |
502 | F(1,0)=ca; |
503 | F(2,1)=F(4,3)=F(5,4)=1; |
504 | F(3,2)=ca + sf/cf*sa; |
006b5f7f |
505 | |
33329428 |
506 | TMatrixD tmp(C,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F)); |
507 | T=new TMatrixD(F,TMatrixD::kMult,tmp); |
508 | } |
006b5f7f |
509 | |
33329428 |
510 | // **** translation ****************** |
511 | { |
512 | Double_t dx=xk-fX; |
006b5f7f |
513 | Double_t f1=fP2, f2=f1 + fP4*dx; |
a9a2d814 |
514 | if (TMath::Abs(f2) >= 0.9999) { |
006b5f7f |
515 | Int_t n=GetNumberOfClusters(); |
7f6ddf58 |
516 | if (n>kWARN) |
517 | cerr<<n<<" AliITStrackV2::Propagate: Propagation failed !\n"; |
006b5f7f |
518 | return 0; |
519 | } |
33329428 |
520 | Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2); |
006b5f7f |
521 | |
33329428 |
522 | fX=xk; |
006b5f7f |
523 | fP0 += dx*(f1+f2)/(r1+r2); |
524 | fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; |
525 | fP2 += dx*fP4; |
526 | |
33329428 |
527 | TMatrixD F(5,6); |
528 | F(0,1)=F(1,2)=F(2,3)=F(3,4)=F(4,5)=1; |
529 | F(0,3)=dx/(r1+r2)*(2+(f1+f2)*(f2/r2+f1/r1)/(r1+r2)); |
530 | F(0,5)=dx*dx/(r1+r2)*(1+(f1+f2)*f2/(r1+r2)); |
531 | F(1,3)=dx*fP3/(f1*r2 + f2*r1)*(2-(f1+f2)*(r2-f1*f2/r2+r1-f2*f1/r1)/(f1*r2 + f2*r1)); |
532 | F(1,4)=dx*(f1+f2)/(f1*r2 + f2*r1); |
533 | F(1,5)=dx*dx*fP3/(f1*r2 + f2*r1)*(1-(f1+f2)*(-f1*f2/r2+r1)/(f1*r2 + f2*r1)); |
534 | F(2,5)=dx; |
535 | F(0,0)=-1/(r1+r2)*((f1+f2)+dx*fP4*(1+(f1+f2)/(r1+r2)*f2/r2)); |
536 | F(1,0)=-fP3/(f1*r2 + f2*r1)*((f1+f2)+dx*fP4*(1+(f1+f2)/(f1*r2 + f2*r1)*(f1*f2/r2-r1))); |
537 | F(2,0)=-fP4; |
538 | |
539 | TMatrixD tmp(*T,TMatrixD::kMult,TMatrixD(TMatrixD::kTransposed, F)); |
540 | delete T; |
541 | TMatrixD C(F,TMatrixD::kMult,tmp); |
006b5f7f |
542 | |
543 | fC00=C(0,0); |
544 | fC10=C(1,0); fC11=C(1,1); |
545 | fC20=C(2,0); fC21=C(2,1); fC22=C(2,2); |
546 | fC30=C(3,0); fC31=C(3,1); fC32=C(3,2); fC33=C(3,3); |
547 | fC40=C(4,0); fC41=C(4,1); fC42=C(4,2); fC43=C(4,3); fC44=C(4,4); |
548 | |
006b5f7f |
549 | if (!Invariant()) { |
33329428 |
550 | fAlpha=alpha; |
551 | fX=x; |
006b5f7f |
552 | fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4; |
553 | fC00=c00; |
554 | fC10=c10; fC11=c11; |
555 | fC20=c20; fC21=c21; fC22=c22; |
556 | fC30=c30; fC31=c31; fC32=c32; fC33=c33; |
557 | fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44; |
558 | return 0; |
559 | } |
33329428 |
560 | } |
006b5f7f |
561 | |
562 | return 1; |
563 | } |
564 | |
a6a6f799 |
565 | Double_t AliITStrackV2::GetD(Double_t x, Double_t y) const { |
006b5f7f |
566 | //------------------------------------------------------------------ |
a6a6f799 |
567 | // This function calculates the transverse impact parameter |
568 | // with respect to a point with global coordinates (x,y) |
006b5f7f |
569 | //------------------------------------------------------------------ |
a6a6f799 |
570 | Double_t xt=fX, yt=fP0; |
571 | |
572 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); |
573 | Double_t a = x*cs + y*sn; |
574 | y = -x*sn + y*cs; x=a; |
575 | xt-=x; yt-=y; |
576 | |
577 | sn=fP4*xt - fP2; cs=fP4*yt + TMath::Sqrt(1.- fP2*fP2); |
578 | a=2*(xt*fP2 - yt*TMath::Sqrt(1.- fP2*fP2))-fP4*(xt*xt + yt*yt); |
006b5f7f |
579 | if (fP4<0) a=-a; |
580 | return a/(1 + TMath::Sqrt(sn*sn + cs*cs)); |
a9a2d814 |
581 | } |
006b5f7f |
582 | |
a9a2d814 |
583 | Int_t AliITStrackV2::Improve(Double_t x0,Double_t yv,Double_t zv) { |
584 | //------------------------------------------------------------------ |
585 | //This function improves angular track parameters |
586 | //------------------------------------------------------------------ |
587 | Double_t dy=fP0-yv, dz=fP1-zv; |
588 | Double_t r2=fX*fX+dy*dy; |
589 | Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); |
590 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); |
591 | x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp())); |
592 | //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0; |
593 | Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33; |
594 | { |
595 | Double_t parp=0.5*(fP4*fX + dy*TMath::Sqrt(4/r2-fP4*fP4)); |
596 | Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl()); |
597 | sigma2p += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2); |
598 | sigma2p += kSigmaYV*kSigmaYV/r2; |
599 | sigma2p += 0.25*fC44*fX*fX; |
600 | Double_t eps2p=sigma2p/(fC22+sigma2p); |
601 | fP0 += fC20/(fC22+sigma2p)*(parp-fP2); |
602 | fP2 = eps2p*fP2 + (1-eps2p)*parp; |
603 | fC22 *= eps2p; |
604 | fC20 *= eps2p; |
605 | } |
606 | { |
607 | Double_t parl=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2)); |
608 | Double_t sigma2l=theta2; |
609 | sigma2l += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2); |
610 | sigma2l += kSigmaZV*kSigmaZV/r2; |
611 | Double_t eps2l=sigma2l/(fC33+sigma2l); |
612 | fP1 += fC31/(fC33+sigma2l)*(parl-fP3); |
613 | fP4 += fC43/(fC33+sigma2l)*(parl-fP3); |
614 | fP3 = eps2l*fP3 + (1-eps2l)*parl; |
615 | fC33 *= eps2l; fC43 *= eps2l; |
616 | fC31 *= eps2l; |
617 | } |
618 | if (!Invariant()) return 0; |
619 | return 1; |
620 | } |
006b5f7f |
621 | |
a9a2d814 |
622 | /* |
006b5f7f |
623 | Int_t AliITStrackV2::Improve(Double_t x0,Double_t yv,Double_t zv) { |
624 | //------------------------------------------------------------------ |
625 | //This function improves angular track parameters |
626 | //------------------------------------------------------------------ |
627 | Double_t dy=fP0-yv, dz=fP1-zv; |
628 | Double_t r2=fX*fX+dy*dy; |
629 | Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); |
7f6ddf58 |
630 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); |
006b5f7f |
631 | x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp())); |
a9a2d814 |
632 | //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0; |
633 | Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33; |
006b5f7f |
634 | |
635 | Double_t par=0.5*(fP4*fX + dy*TMath::Sqrt(4/r2-fP4*fP4)); |
636 | Double_t sigma2 = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl()); |
637 | sigma2 += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2); |
638 | sigma2 += kSigmaYV*kSigmaYV/r2; |
639 | sigma2 += 0.25*fC44*fX*fX; |
640 | Double_t eps2=sigma2/(fC22+sigma2), eps=TMath::Sqrt(eps2); |
641 | if (10*r2*fC44<fC22) { |
642 | fP2 = eps2*fP2 + (1-eps2)*par; |
643 | fC22*=eps2; fC21*=eps; fC20*=eps; fC32*=eps; fC42*=eps; |
644 | } |
645 | |
646 | par=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2)); |
647 | sigma2=theta2; |
648 | sigma2 += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2); |
649 | sigma2 += kSigmaZV*kSigmaZV/r2; |
650 | eps2=sigma2/(fC33+sigma2); eps=TMath::Sqrt(eps2); |
651 | Double_t tgl=fP3; |
652 | fP3 = eps2*fP3 + (1-eps2)*par; |
653 | fC33*=eps2; fC32*=eps; fC31*=eps; fC30*=eps; fC43*=eps; |
654 | |
655 | eps=TMath::Sqrt((1+fP3*fP3)/(1+tgl*tgl)); |
656 | fP4*=eps; |
657 | fC44*=eps*eps; fC43*=eps;fC42*=eps; fC41*=eps; fC40*=eps; |
658 | |
659 | if (!Invariant()) return 0; |
660 | return 1; |
661 | } |
006b5f7f |
662 | */ |
14825d5a |
663 | void AliITStrackV2::ResetCovariance() { |
664 | //------------------------------------------------------------------ |
665 | //This function makes a track forget its history :) |
666 | //------------------------------------------------------------------ |
667 | |
668 | fC00*=10.; |
669 | fC10=0.; fC11*=10.; |
670 | fC20=0.; fC21=0.; fC22*=10.; |
671 | fC30=0.; fC31=0.; fC32=0.; fC33*=10.; |
672 | fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.; |
673 | |
674 | } |
23efe5f1 |
675 | |
676 | void AliITStrackV2::CookdEdx(Double_t low, Double_t up) { |
677 | //----------------------------------------------------------------- |
a9a2d814 |
678 | // This function calculates dE/dX within the "low" and "up" cuts. |
679 | // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch |
23efe5f1 |
680 | //----------------------------------------------------------------- |
681 | Int_t i; |
a9a2d814 |
682 | Int_t nc=4; |
23efe5f1 |
683 | // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1 |
684 | // Take only SSD and SDD |
23efe5f1 |
685 | |
a9a2d814 |
686 | Int_t swap;//stupid sorting |
23efe5f1 |
687 | do { |
688 | swap=0; |
689 | for (i=0; i<nc-1; i++) { |
690 | if (fdEdxSample[i]<=fdEdxSample[i+1]) continue; |
691 | Float_t tmp=fdEdxSample[i]; |
692 | fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp; |
693 | swap++; |
694 | } |
695 | } while (swap); |
696 | |
a9a2d814 |
697 | Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX |
698 | // values from four ones choose |
699 | // nu=2 |
23efe5f1 |
700 | Float_t dedx=0; |
a9a2d814 |
701 | for (i=nl; i<nu; i++) dedx += fdEdxSample[i]; |
702 | dedx /= (nu-nl); |
23efe5f1 |
703 | |
23efe5f1 |
704 | SetdEdx(dedx); |
705 | } |