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006b5f7f | 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 | ||
66e811e2 | 16 | /////////////////////////////////////////////////////////////////////////// |
006b5f7f | 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 |
66e811e2 | 21 | /////////////////////////////////////////////////////////////////////////// |
006b5f7f | 22 | #include <TMath.h> |
006b5f7f | 23 | |
24 | #include "AliCluster.h" | |
83d73500 | 25 | #include "AliESDtrack.h" |
006b5f7f | 26 | #include "AliITStrackV2.h" |
27 | ||
1aedd96e | 28 | ClassImp(AliITStrackV2) |
8676d691 | 29 | |
e43c066c | 30 | const Int_t kWARN=5; |
31 | ||
22b13da0 | 32 | //____________________________________________________________________________ |
e6ba4672 | 33 | AliITStrackV2::AliITStrackV2():AliKalmanTrack(), |
22b13da0 | 34 | fX(0), |
35 | fAlpha(0), | |
36 | fdEdx(0), | |
37 | fP0(0), | |
38 | fP1(0), | |
39 | fP2(0), | |
40 | fP3(0), | |
41 | fP4(0), | |
42 | fC00(0), | |
43 | fC10(0), | |
44 | fC11(0), | |
45 | fC20(0), | |
46 | fC21(0), | |
47 | fC22(0), | |
48 | fC30(0), | |
49 | fC31(0), | |
50 | fC32(0), | |
51 | fC33(0), | |
52 | fC40(0), | |
53 | fC41(0), | |
54 | fC42(0), | |
55 | fC43(0), | |
83d73500 | 56 | fC44(0), |
57 | fESDtrack(0) | |
e43c066c | 58 | { |
ef7253ac | 59 | for(Int_t i=0; i<2*kMaxLayer; i++) fIndex[i]=-1; |
e43c066c | 60 | for(Int_t i=0; i<4; i++) fdEdxSample[i]=0; |
e43c066c | 61 | } |
62 | ||
83d73500 | 63 | |
83d73500 | 64 | //____________________________________________________________________________ |
67c3dcbe | 65 | AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c) throw (const Char_t *) : |
83d73500 | 66 | AliKalmanTrack() { |
67 | //------------------------------------------------------------------ | |
67c3dcbe | 68 | // Conversion ESD track -> ITS track. |
69 | // If c==kTRUE, create the ITS track out of the constrained params. | |
83d73500 | 70 | //------------------------------------------------------------------ |
71 | SetNumberOfClusters(t.GetITSclusters(fIndex)); | |
72 | SetLabel(t.GetLabel()); | |
73 | SetMass(t.GetMass()); | |
e43c066c | 74 | // |
75 | // | |
83d73500 | 76 | |
77 | fdEdx=t.GetITSsignal(); | |
78 | fAlpha = t.GetAlpha(); | |
79 | if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi(); | |
80 | else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi(); | |
81 | ||
9b280d80 | 82 | //Conversion of the track parameters |
67c3dcbe | 83 | Double_t x,p[5]; |
c0b978f0 | 84 | if (c) t.GetConstrainedExternalParameters(fAlpha,x,p); |
67c3dcbe | 85 | else t.GetExternalParameters(x,p); |
c84a5e9e | 86 | fX=x; |
006b5f7f | 87 | fP0=p[0]; |
c84a5e9e | 88 | fP1=p[1]; SaveLocalConvConst(); |
006b5f7f | 89 | fP2=p[2]; |
c84a5e9e | 90 | fP3=p[3]; x=GetLocalConvConst(); |
006b5f7f | 91 | fP4=p[4]/x; |
92 | ||
9b280d80 | 93 | //Conversion of the covariance matrix |
67c3dcbe | 94 | Double_t cv[15]; |
95 | if (c) t.GetConstrainedExternalCovariance(cv); | |
96 | else t.GetExternalCovariance(cv); | |
97 | fC00=cv[0 ]; | |
98 | fC10=cv[1 ]; fC11=cv[2 ]; | |
99 | fC20=cv[3 ]; fC21=cv[4 ]; fC22=cv[5 ]; | |
100 | fC30=cv[6 ]; fC31=cv[7 ]; fC32=cv[8 ]; fC33=cv[9 ]; | |
101 | fC40=cv[10]/x; fC41=cv[11]/x; fC42=cv[12]/x; fC43=cv[13]/x; fC44=cv[14]/x/x; | |
006b5f7f | 102 | |
83d73500 | 103 | if (t.GetStatus()&AliESDtrack::kTIME) { |
104 | StartTimeIntegral(); | |
105 | Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times); | |
106 | SetIntegratedLength(t.GetIntegratedLength()); | |
107 | } | |
108 | fESDtrack=&t; | |
e43c066c | 109 | |
81e97e0d | 110 | // if (!Invariant()) throw "AliITStrackV2: conversion failed !\n"; |
68b8060b | 111 | for(Int_t i=0; i<4; i++) fdEdxSample[i]=0; |
006b5f7f | 112 | } |
113 | ||
15dd636f | 114 | void AliITStrackV2::UpdateESDtrack(ULong_t flags) const { |
83d73500 | 115 | fESDtrack->UpdateTrackParams(this,flags); |
116 | } | |
117 | ||
006b5f7f | 118 | //____________________________________________________________________________ |
119 | AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) : AliKalmanTrack(t) { | |
120 | //------------------------------------------------------------------ | |
121 | //Copy constructor | |
122 | //------------------------------------------------------------------ | |
123 | fX=t.fX; | |
124 | fAlpha=t.fAlpha; | |
125 | fdEdx=t.fdEdx; | |
126 | ||
127 | fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4; | |
128 | ||
129 | fC00=t.fC00; | |
130 | fC10=t.fC10; fC11=t.fC11; | |
131 | fC20=t.fC20; fC21=t.fC21; fC22=t.fC22; | |
132 | fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33; | |
133 | fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44; | |
134 | ||
ef7253ac | 135 | Int_t i; |
136 | for (i=0; i<2*kMaxLayer; i++) fIndex[i]=t.fIndex[i]; | |
137 | for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i]; | |
138 | ||
83d73500 | 139 | fESDtrack=t.fESDtrack; |
006b5f7f | 140 | } |
a9a2d814 | 141 | |
006b5f7f | 142 | //_____________________________________________________________________________ |
143 | Int_t AliITStrackV2::Compare(const TObject *o) const { | |
144 | //----------------------------------------------------------------- | |
145 | // This function compares tracks according to the their curvature | |
146 | //----------------------------------------------------------------- | |
7f6ddf58 | 147 | AliITStrackV2 *t=(AliITStrackV2*)o; |
a9a2d814 | 148 | //Double_t co=TMath::Abs(t->Get1Pt()); |
149 | //Double_t c =TMath::Abs(Get1Pt()); | |
15dd636f | 150 | Double_t co=t->GetSigmaY2()*t->GetSigmaZ2(); |
151 | Double_t c =GetSigmaY2()*GetSigmaZ2(); | |
006b5f7f | 152 | if (c>co) return 1; |
153 | else if (c<co) return -1; | |
154 | return 0; | |
155 | } | |
156 | ||
157 | //_____________________________________________________________________________ | |
158 | void AliITStrackV2::GetExternalCovariance(Double_t cc[15]) const { | |
159 | //------------------------------------------------------------------------- | |
160 | // This function returns an external representation of the covriance matrix. | |
161 | // (See comments in AliTPCtrack.h about external track representation) | |
162 | //------------------------------------------------------------------------- | |
c84a5e9e | 163 | Double_t a=GetLocalConvConst(); |
006b5f7f | 164 | |
165 | cc[0 ]=fC00; | |
166 | cc[1 ]=fC10; cc[2 ]=fC11; | |
167 | cc[3 ]=fC20; cc[4 ]=fC21; cc[5 ]=fC22; | |
168 | cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=fC32; cc[9 ]=fC33; | |
169 | cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=fC42*a; cc[13]=fC43*a; cc[14]=fC44*a*a; | |
170 | } | |
171 | ||
172 | //____________________________________________________________________________ | |
a9a2d814 | 173 | Int_t AliITStrackV2::PropagateToVertex(Double_t d,Double_t x0) { |
006b5f7f | 174 | //------------------------------------------------------------------ |
175 | //This function propagates a track to the minimal distance from the origin | |
176 | //------------------------------------------------------------------ | |
5b316485 | 177 | //Double_t xv=fP2*(fX*fP2 - fP0*TMath::Sqrt(1.- fP2*fP2)); //linear approxim. |
178 | Double_t tgf=-(fP4*fX - fP2)/(fP4*fP0 + TMath::Sqrt(1 - fP2*fP2)); | |
179 | Double_t snf=tgf/TMath::Sqrt(1.+ tgf*tgf); | |
180 | Double_t xv=(snf - fP2)/fP4 + fX; | |
181 | return PropagateTo(xv,d,x0); | |
006b5f7f | 182 | } |
183 | ||
184 | //____________________________________________________________________________ | |
185 | Int_t AliITStrackV2:: | |
186 | GetGlobalXYZat(Double_t xk, Double_t &x, Double_t &y, Double_t &z) const { | |
187 | //------------------------------------------------------------------ | |
188 | //This function returns a track position in the global system | |
189 | //------------------------------------------------------------------ | |
190 | Double_t dx=xk-fX; | |
191 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
a9a2d814 | 192 | if (TMath::Abs(f2) >= 0.9999) { |
7f6ddf58 | 193 | Int_t n=GetNumberOfClusters(); |
194 | if (n>kWARN) | |
8676d691 | 195 | Warning("GetGlobalXYZat","Propagation failed (%d) !\n",n); |
006b5f7f | 196 | return 0; |
197 | } | |
198 | ||
199 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); | |
200 | ||
201 | Double_t yk = fP0 + dx*(f1+f2)/(r1+r2); | |
202 | Double_t zk = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
203 | ||
204 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); | |
205 | x = xk*cs - yk*sn; | |
206 | y = xk*sn + yk*cs; | |
207 | z = zk; | |
208 | ||
209 | return 1; | |
210 | } | |
211 | ||
212 | //_____________________________________________________________________________ | |
213 | Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const | |
214 | { | |
215 | //----------------------------------------------------------------- | |
216 | // This function calculates a predicted chi2 increment. | |
217 | //----------------------------------------------------------------- | |
218 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
219 | r00+=fC00; r01+=fC10; r11+=fC11; | |
babd135a | 220 | // |
006b5f7f | 221 | Double_t det=r00*r11 - r01*r01; |
7f6ddf58 | 222 | if (TMath::Abs(det) < 1.e-30) { |
006b5f7f | 223 | Int_t n=GetNumberOfClusters(); |
7f6ddf58 | 224 | if (n>kWARN) |
8676d691 | 225 | Warning("GetPredictedChi2","Singular matrix (%d) !\n",n); |
006b5f7f | 226 | return 1e10; |
227 | } | |
228 | Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01; | |
33329428 | 229 | |
006b5f7f | 230 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; |
33329428 | 231 | |
006b5f7f | 232 | return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det; |
233 | } | |
234 | ||
006b5f7f | 235 | //____________________________________________________________________________ |
a9a2d814 | 236 | Int_t AliITStrackV2::CorrectForMaterial(Double_t d, Double_t x0) { |
237 | //------------------------------------------------------------------ | |
238 | //This function corrects the track parameters for crossed material | |
239 | //------------------------------------------------------------------ | |
e43c066c | 240 | Double_t p2=(1.+ fP3*fP3)/(Get1Pt()*Get1Pt()); |
15dd636f | 241 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); |
a9a2d814 | 242 | d*=TMath::Sqrt((1.+ fP3*fP3)/(1.- fP2*fP2)); |
243 | ||
244 | //Multiple scattering****************** | |
245 | if (d!=0) { | |
33329428 | 246 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(d); |
247 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33; | |
a9a2d814 | 248 | fC22 += theta2*(1.- fP2*fP2)*(1. + fP3*fP3); |
249 | fC33 += theta2*(1. + fP3*fP3)*(1. + fP3*fP3); | |
250 | fC43 += theta2*fP3*fP4*(1. + fP3*fP3); | |
251 | fC44 += theta2*fP3*fP4*fP3*fP4; | |
252 | } | |
253 | ||
254 | //Energy losses************************ | |
255 | if (x0!=0.) { | |
256 | d*=x0; | |
15dd636f | 257 | Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d; |
258 | if (beta2/(1-beta2)>3.5*3.5) | |
83d73500 | 259 | dE=0.153e-3/beta2*(log(3.5*5940)+0.5*log(beta2/(1-beta2)) - beta2)*d; |
15dd636f | 260 | |
261 | fP4*=(1.- TMath::Sqrt(p2+GetMass()*GetMass())/p2*dE); | |
a9a2d814 | 262 | } |
263 | ||
264 | if (!Invariant()) return 0; | |
265 | ||
266 | return 1; | |
267 | } | |
268 | ||
269 | //____________________________________________________________________________ | |
270 | Int_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) { | |
006b5f7f | 271 | //------------------------------------------------------------------ |
272 | //This function propagates a track | |
273 | //------------------------------------------------------------------ | |
274 | Double_t x1=fX, x2=xk, dx=x2-x1; | |
275 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
c84a5e9e | 276 | if (TMath::Abs(f2) >= 0.98) { |
81e97e0d | 277 | // MI change - don't propagate highly inclined tracks |
278 | // covariance matrix distorted | |
c84a5e9e | 279 | //Int_t n=GetNumberOfClusters(); |
280 | //if (n>kWARN) | |
281 | // Warning("PropagateTo","Propagation failed !\n",n); | |
006b5f7f | 282 | return 0; |
283 | } | |
c84a5e9e | 284 | Double_t lcc=GetLocalConvConst(); |
006b5f7f | 285 | |
f29dbb4b | 286 | // old position [SR, GSI, 17.02.2003] |
287 | Double_t oldX = fX, oldY = fP0, oldZ = fP1; | |
288 | ||
006b5f7f | 289 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); |
290 | ||
291 | fP0 += dx*(f1+f2)/(r1+r2); | |
292 | fP1 += dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
293 | fP2 += dx*fP4; | |
294 | ||
295 | //f = F - 1 | |
296 | ||
297 | Double_t f02= dx/(r1*r1*r1); | |
298 | Double_t f04=0.5*dx*dx/(r1*r1*r1); | |
299 | Double_t f12= dx*fP3*f1/(r1*r1*r1); | |
300 | Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1); | |
301 | Double_t f13= dx/r1; | |
302 | Double_t f24= dx; | |
303 | ||
304 | //b = C*ft | |
305 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; | |
306 | Double_t b02=f24*fC40; | |
307 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; | |
308 | Double_t b12=f24*fC41; | |
309 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; | |
310 | Double_t b22=f24*fC42; | |
311 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; | |
312 | Double_t b42=f24*fC44; | |
313 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; | |
314 | Double_t b32=f24*fC43; | |
315 | ||
316 | //a = f*b = f*C*ft | |
317 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42; | |
318 | Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32; | |
319 | Double_t a22=f24*b42; | |
320 | ||
321 | //F*C*Ft = C + (b + bt + a) | |
322 | fC00 += b00 + b00 + a00; | |
323 | fC10 += b10 + b01 + a01; | |
324 | fC20 += b20 + b02 + a02; | |
325 | fC30 += b30; | |
326 | fC40 += b40; | |
327 | fC11 += b11 + b11 + a11; | |
328 | fC21 += b21 + b12 + a12; | |
329 | fC31 += b31; | |
330 | fC41 += b41; | |
331 | fC22 += b22 + b22 + a22; | |
332 | fC32 += b32; | |
333 | fC42 += b42; | |
334 | ||
335 | fX=x2; | |
336 | ||
c84a5e9e | 337 | //Change of the magnetic field ************* |
338 | SaveLocalConvConst(); | |
339 | fP4*=lcc/GetLocalConvConst(); | |
340 | ||
a9a2d814 | 341 | if (!CorrectForMaterial(d,x0)) return 0; |
006b5f7f | 342 | |
f29dbb4b | 343 | // Integrated Time [SR, GSI, 17.02.2003] |
880f41b9 | 344 | if (IsStartedTimeIntegral() && fX>oldX) { |
8676d691 | 345 | Double_t l2 = (fX-oldX)*(fX-oldX)+(fP0-oldY)*(fP0-oldY)+ |
346 | (fP1-oldZ)*(fP1-oldZ); | |
f29dbb4b | 347 | AddTimeStep(TMath::Sqrt(l2)); |
348 | } | |
349 | // | |
350 | ||
006b5f7f | 351 | return 1; |
352 | } | |
353 | ||
354 | //____________________________________________________________________________ | |
355 | Int_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, UInt_t index) { | |
356 | //------------------------------------------------------------------ | |
357 | //This function updates track parameters | |
358 | //------------------------------------------------------------------ | |
359 | Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4; | |
360 | Double_t c00=fC00; | |
361 | Double_t c10=fC10, c11=fC11; | |
362 | Double_t c20=fC20, c21=fC21, c22=fC22; | |
363 | Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33; | |
364 | Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44; | |
365 | ||
366 | ||
367 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
368 | r00+=fC00; r01+=fC10; r11+=fC11; | |
369 | Double_t det=r00*r11 - r01*r01; | |
370 | Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det; | |
371 | ||
babd135a | 372 | |
006b5f7f | 373 | Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11; |
374 | Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11; | |
375 | Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11; | |
376 | Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11; | |
377 | Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11; | |
378 | ||
379 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; | |
380 | Double_t sf=fP2 + k20*dy + k21*dz; | |
7f6ddf58 | 381 | |
006b5f7f | 382 | fP0 += k00*dy + k01*dz; |
383 | fP1 += k10*dy + k11*dz; | |
384 | fP2 = sf; | |
385 | fP3 += k30*dy + k31*dz; | |
386 | fP4 += k40*dy + k41*dz; | |
387 | ||
388 | Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40; | |
389 | Double_t c12=fC21, c13=fC31, c14=fC41; | |
390 | ||
391 | fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11; | |
392 | fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13; | |
393 | fC40-=k00*c04+k01*c14; | |
394 | ||
395 | fC11-=k10*c01+k11*fC11; | |
396 | fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13; | |
397 | fC41-=k10*c04+k11*c14; | |
398 | ||
399 | fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13; | |
400 | fC42-=k20*c04+k21*c14; | |
401 | ||
402 | fC33-=k30*c03+k31*c13; | |
403 | fC43-=k30*c04+k31*c14; | |
404 | ||
405 | fC44-=k40*c04+k41*c14; | |
406 | ||
407 | if (!Invariant()) { | |
408 | fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4; | |
409 | fC00=c00; | |
410 | fC10=c10; fC11=c11; | |
411 | fC20=c20; fC21=c21; fC22=c22; | |
412 | fC30=c30; fC31=c31; fC32=c32; fC33=c33; | |
413 | fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44; | |
414 | return 0; | |
415 | } | |
416 | ||
67c3dcbe | 417 | if (chi2<0) return 1; |
418 | ||
006b5f7f | 419 | Int_t n=GetNumberOfClusters(); |
420 | fIndex[n]=index; | |
421 | SetNumberOfClusters(n+1); | |
422 | SetChi2(GetChi2()+chi2); | |
423 | ||
424 | return 1; | |
425 | } | |
426 | ||
006b5f7f | 427 | Int_t AliITStrackV2::Invariant() const { |
428 | //------------------------------------------------------------------ | |
429 | // This function is for debugging purpose only | |
430 | //------------------------------------------------------------------ | |
7f6ddf58 | 431 | Int_t n=GetNumberOfClusters(); |
432 | ||
a9a2d814 | 433 | if (TMath::Abs(fP2)>=0.9999){ |
8676d691 | 434 | if (n>kWARN) Warning("Invariant","fP2=%f\n",fP2); |
a9a2d814 | 435 | return 0; |
436 | } | |
437 | if (fC00<=0 || fC00>9.) { | |
8676d691 | 438 | if (n>kWARN) Warning("Invariant","fC00=%f\n",fC00); |
a9a2d814 | 439 | return 0; |
440 | } | |
441 | if (fC11<=0 || fC11>9.) { | |
8676d691 | 442 | if (n>kWARN) Warning("Invariant","fC11=%f\n",fC11); |
a9a2d814 | 443 | return 0; |
444 | } | |
445 | if (fC22<=0 || fC22>1.) { | |
8676d691 | 446 | if (n>kWARN) Warning("Invariant","fC22=%f\n",fC22); |
a9a2d814 | 447 | return 0; |
448 | } | |
449 | if (fC33<=0 || fC33>1.) { | |
8676d691 | 450 | if (n>kWARN) Warning("Invariant","fC33=%f\n",fC33); |
a9a2d814 | 451 | return 0; |
452 | } | |
453 | if (fC44<=0 || fC44>6e-5) { | |
8676d691 | 454 | if (n>kWARN) Warning("Invariant","fC44=%f\n",fC44); |
a9a2d814 | 455 | return 0; |
14825d5a | 456 | } |
14825d5a | 457 | return 1; |
006b5f7f | 458 | } |
459 | ||
460 | //____________________________________________________________________________ | |
a9a2d814 | 461 | Int_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) { |
006b5f7f | 462 | //------------------------------------------------------------------ |
463 | //This function propagates a track | |
464 | //------------------------------------------------------------------ | |
33329428 | 465 | Double_t alpha=fAlpha, x=fX; |
006b5f7f | 466 | Double_t p0=fP0,p1=fP1,p2=fP2,p3=fP3,p4=fP4; |
467 | Double_t c00=fC00; | |
468 | Double_t c10=fC10, c11=fC11; | |
469 | Double_t c20=fC20, c21=fC21, c22=fC22; | |
470 | Double_t c30=fC30, c31=fC31, c32=fC32, c33=fC33; | |
471 | Double_t c40=fC40, c41=fC41, c42=fC42, c43=fC43, c44=fC44; | |
472 | ||
33329428 | 473 | if (alp < -TMath::Pi()) alp += 2*TMath::Pi(); |
474 | else if (alp >= TMath::Pi()) alp -= 2*TMath::Pi(); | |
475 | Double_t ca=TMath::Cos(alp-fAlpha), sa=TMath::Sin(alp-fAlpha); | |
476 | Double_t sf=fP2, cf=TMath::Sqrt(1.- fP2*fP2); | |
006b5f7f | 477 | |
33329428 | 478 | // **** rotation ********************** |
479 | { | |
006b5f7f | 480 | fAlpha = alp; |
33329428 | 481 | fX = x*ca + p0*sa; |
482 | fP0= -x*sa + p0*ca; | |
483 | fP2= sf*ca - cf*sa; | |
484 | ||
c219fd63 | 485 | Double_t rr=(ca+sf/cf*sa); |
486 | ||
487 | fC00 *= (ca*ca); | |
488 | fC10 *= ca; | |
489 | fC20 *= ca*rr; | |
490 | fC30 *= ca; | |
491 | fC40 *= ca; | |
492 | //fC11 = fC11; | |
493 | fC21 *= rr; | |
494 | //fC31 = fC31; | |
495 | //fC41 = fC41; | |
496 | fC22 *= rr*rr; | |
497 | fC32 *= rr; | |
498 | fC42 *= rr; | |
499 | //fC33=fC33; | |
500 | //fC43=fC43; | |
501 | //fC44=fC44; | |
502 | ||
33329428 | 503 | } |
006b5f7f | 504 | |
33329428 | 505 | // **** translation ****************** |
506 | { | |
507 | Double_t dx=xk-fX; | |
006b5f7f | 508 | Double_t f1=fP2, f2=f1 + fP4*dx; |
c84a5e9e | 509 | if (TMath::Abs(f2) >= 0.98) { |
81e97e0d | 510 | // don't propagate highly inclined tracks MI |
006b5f7f | 511 | return 0; |
512 | } | |
c84a5e9e | 513 | // Int_t n=GetNumberOfClusters(); |
514 | // if (n>kWARN) | |
515 | // Warning("Propagate","Propagation failed (%d) !\n",n); | |
516 | // return 0; | |
517 | //} | |
518 | Double_t lcc=GetLocalConvConst(); | |
519 | ||
33329428 | 520 | Double_t r1=TMath::Sqrt(1.- f1*f1), r2=TMath::Sqrt(1.- f2*f2); |
c84a5e9e | 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 | ||
c84a5e9e | 527 | //Change of the magnetic field ************* |
528 | SaveLocalConvConst(); | |
529 | fP4*=lcc/GetLocalConvConst(); | |
530 | ||
c219fd63 | 531 | //f = F - 1 |
532 | ||
533 | Double_t f02= dx/(r1*r1*r1); | |
534 | Double_t f04=0.5*dx*dx/(r1*r1*r1); | |
535 | Double_t f12= dx*fP3*f1/(r1*r1*r1); | |
536 | Double_t f14=0.5*dx*dx*fP3*f1/(r1*r1*r1); | |
537 | Double_t f13= dx/r1; | |
538 | Double_t f24= dx; | |
539 | ||
540 | //b = C*ft | |
541 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; | |
542 | Double_t b02=f24*fC40; | |
543 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; | |
544 | Double_t b12=f24*fC41; | |
545 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; | |
546 | Double_t b22=f24*fC42; | |
547 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; | |
548 | Double_t b42=f24*fC44; | |
549 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; | |
550 | Double_t b32=f24*fC43; | |
551 | ||
552 | //a = f*b = f*C*ft | |
553 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a02=f02*b22+f04*b42; | |
554 | Double_t a11=f12*b21+f14*b41+f13*b31,a12=f12*b22+f14*b42+f13*b32; | |
555 | Double_t a22=f24*b42; | |
556 | ||
557 | //F*C*Ft = C + (b + bt + a) | |
558 | fC00 += b00 + b00 + a00; | |
559 | fC10 += b10 + b01 + a01; | |
560 | fC20 += b20 + b02 + a02; | |
561 | fC30 += b30; | |
562 | fC40 += b40; | |
563 | fC11 += b11 + b11 + a11; | |
564 | fC21 += b21 + b12 + a12; | |
565 | fC31 += b31; | |
566 | fC41 += b41; | |
567 | fC22 += b22 + b22 + a22; | |
568 | fC32 += b32; | |
569 | fC42 += b42; | |
006b5f7f | 570 | |
006b5f7f | 571 | if (!Invariant()) { |
33329428 | 572 | fAlpha=alpha; |
573 | fX=x; | |
006b5f7f | 574 | fP0=p0; fP1=p1; fP2=p2; fP3=p3; fP4=p4; |
575 | fC00=c00; | |
576 | fC10=c10; fC11=c11; | |
577 | fC20=c20; fC21=c21; fC22=c22; | |
578 | fC30=c30; fC31=c31; fC32=c32; fC33=c33; | |
579 | fC40=c40; fC41=c41; fC42=c42; fC43=c43; fC44=c44; | |
580 | return 0; | |
581 | } | |
33329428 | 582 | } |
006b5f7f | 583 | |
584 | return 1; | |
585 | } | |
586 | ||
c219fd63 | 587 | |
a6a6f799 | 588 | Double_t AliITStrackV2::GetD(Double_t x, Double_t y) const { |
006b5f7f | 589 | //------------------------------------------------------------------ |
a6a6f799 | 590 | // This function calculates the transverse impact parameter |
591 | // with respect to a point with global coordinates (x,y) | |
006b5f7f | 592 | //------------------------------------------------------------------ |
a6a6f799 | 593 | Double_t xt=fX, yt=fP0; |
594 | ||
595 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); | |
596 | Double_t a = x*cs + y*sn; | |
597 | y = -x*sn + y*cs; x=a; | |
598 | xt-=x; yt-=y; | |
599 | ||
600 | sn=fP4*xt - fP2; cs=fP4*yt + TMath::Sqrt(1.- fP2*fP2); | |
601 | a=2*(xt*fP2 - yt*TMath::Sqrt(1.- fP2*fP2))-fP4*(xt*xt + yt*yt); | |
791f9a2a | 602 | return -a/(1 + TMath::Sqrt(sn*sn + cs*cs)); |
603 | } | |
604 | ||
605 | void | |
606 | AliITStrackV2::GetDZ(Double_t x, Double_t y, Double_t z, Float_t dz[2]) const { | |
607 | //------------------------------------------------------------------ | |
608 | // This function calculates the transverse and longitudinal impact parameters | |
609 | // with respect to a point with global coordinates (x,y,z) | |
610 | //------------------------------------------------------------------ | |
611 | Double_t f1 = fP2, r1 = TMath::Sqrt(1. - f1*f1); | |
612 | Double_t xt=fX, yt=fP0; | |
613 | Double_t sn=TMath::Sin(fAlpha), cs=TMath::Cos(fAlpha); | |
614 | Double_t a = x*cs + y*sn; | |
615 | y = -x*sn + y*cs; x=a; | |
616 | xt-=x; yt-=y; | |
617 | ||
618 | Double_t rp4=fP4; | |
619 | if (TMath::Abs(rp4) < kAlmost0) { | |
620 | dz[0] = -(xt*f1 - yt*r1); | |
621 | dz[1] = fP1 + (dz[0]*f1 - xt)/r1*fP3 - z; | |
622 | return; | |
623 | } | |
624 | ||
625 | sn=rp4*xt - f1; cs=rp4*yt + r1; | |
626 | a=2*(xt*f1 - yt*r1)-rp4*(xt*xt + yt*yt); | |
627 | Double_t rr=TMath::Sqrt(sn*sn + cs*cs); | |
628 | dz[0] = -a/(1 + rr); | |
629 | Double_t f2 = -sn/rr, r2 = TMath::Sqrt(1. - f2*f2); | |
630 | dz[1] = fP1 + fP3/rp4*TMath::ASin(f2*r1 - f1*r2) - z; | |
a9a2d814 | 631 | } |
006b5f7f | 632 | |
babd135a | 633 | Double_t AliITStrackV2::GetZat(Double_t x) const { |
634 | //------------------------------------------------------------------ | |
635 | // This function calculates the z at given x point - in current coordinate system | |
636 | //------------------------------------------------------------------ | |
637 | Double_t x1=fX, x2=x, dx=x2-x1; | |
638 | // | |
639 | Double_t f1=fP2, f2=f1 + fP4*dx; | |
640 | if (TMath::Abs(f2) >= 0.9999) { | |
641 | return 10000000; | |
642 | } | |
babd135a | 643 | Double_t r1=sqrt(1.- f1*f1), r2=sqrt(1.- f2*f2); |
644 | Double_t z = fP1 + dx*(f1+f2)/(f1*r2 + f2*r1)*fP3; | |
645 | return z; | |
646 | } | |
647 | ||
648 | ||
649 | ||
650 | ||
8676d691 | 651 | Int_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) { |
a9a2d814 | 652 | //------------------------------------------------------------------ |
653 | //This function improves angular track parameters | |
654 | //------------------------------------------------------------------ | |
8676d691 | 655 | Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha); |
656 | //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex | |
657 | Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the | |
658 | Double_t zv = xyz[2]; // local frame | |
a9a2d814 | 659 | Double_t dy=fP0-yv, dz=fP1-zv; |
660 | Double_t r2=fX*fX+dy*dy; | |
661 | Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); | |
662 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); | |
663 | x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp())); | |
8676d691 | 664 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0; |
665 | //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33; | |
a9a2d814 | 666 | { |
25d954aa | 667 | Double_t dummy=4/r2-fP4*fP4; |
668 | if (dummy < 0) return 0; | |
669 | Double_t parp=0.5*(fP4*fX + dy*TMath::Sqrt(dummy)); | |
a9a2d814 | 670 | Double_t sigma2p = theta2*(1.- GetSnp()*GetSnp())*(1. + GetTgl()*GetTgl()); |
671 | sigma2p += fC00/r2*(1.- dy*dy/r2)*(1.- dy*dy/r2); | |
8676d691 | 672 | sigma2p += ers[1]*ers[1]/r2; |
a9a2d814 | 673 | sigma2p += 0.25*fC44*fX*fX; |
674 | Double_t eps2p=sigma2p/(fC22+sigma2p); | |
675 | fP0 += fC20/(fC22+sigma2p)*(parp-fP2); | |
676 | fP2 = eps2p*fP2 + (1-eps2p)*parp; | |
677 | fC22 *= eps2p; | |
678 | fC20 *= eps2p; | |
679 | } | |
680 | { | |
681 | Double_t parl=0.5*fP4*dz/TMath::ASin(0.5*fP4*TMath::Sqrt(r2)); | |
682 | Double_t sigma2l=theta2; | |
683 | sigma2l += fC11/r2+fC00*dy*dy*dz*dz/(r2*r2*r2); | |
8676d691 | 684 | sigma2l += ers[2]*ers[2]/r2; |
a9a2d814 | 685 | Double_t eps2l=sigma2l/(fC33+sigma2l); |
686 | fP1 += fC31/(fC33+sigma2l)*(parl-fP3); | |
687 | fP4 += fC43/(fC33+sigma2l)*(parl-fP3); | |
688 | fP3 = eps2l*fP3 + (1-eps2l)*parl; | |
689 | fC33 *= eps2l; fC43 *= eps2l; | |
690 | fC31 *= eps2l; | |
691 | } | |
692 | if (!Invariant()) return 0; | |
693 | return 1; | |
694 | } | |
006b5f7f | 695 | |
14825d5a | 696 | void AliITStrackV2::ResetCovariance() { |
697 | //------------------------------------------------------------------ | |
698 | //This function makes a track forget its history :) | |
699 | //------------------------------------------------------------------ | |
700 | ||
701 | fC00*=10.; | |
702 | fC10=0.; fC11*=10.; | |
703 | fC20=0.; fC21=0.; fC22*=10.; | |
704 | fC30=0.; fC31=0.; fC32=0.; fC33*=10.; | |
705 | fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.; | |
706 | ||
707 | } | |
23efe5f1 | 708 | |
709 | void AliITStrackV2::CookdEdx(Double_t low, Double_t up) { | |
710 | //----------------------------------------------------------------- | |
a9a2d814 | 711 | // This function calculates dE/dX within the "low" and "up" cuts. |
712 | // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch | |
23efe5f1 | 713 | //----------------------------------------------------------------- |
23efe5f1 | 714 | // The clusters order is: SSD-2, SSD-1, SDD-2, SDD-1, SPD-2, SPD-1 |
c0dd5278 | 715 | |
716 | Int_t i; | |
717 | Int_t nc=0; | |
718 | for (i=0; i<GetNumberOfClusters(); i++) { | |
719 | Int_t idx=GetClusterIndex(i); | |
720 | idx=(idx&0xf0000000)>>28; | |
721 | if (idx>1) nc++; // Take only SSD and SDD | |
722 | } | |
23efe5f1 | 723 | |
a9a2d814 | 724 | Int_t swap;//stupid sorting |
23efe5f1 | 725 | do { |
726 | swap=0; | |
727 | for (i=0; i<nc-1; i++) { | |
728 | if (fdEdxSample[i]<=fdEdxSample[i+1]) continue; | |
729 | Float_t tmp=fdEdxSample[i]; | |
730 | fdEdxSample[i]=fdEdxSample[i+1]; fdEdxSample[i+1]=tmp; | |
731 | swap++; | |
732 | } | |
733 | } while (swap); | |
734 | ||
a9a2d814 | 735 | Int_t nl=Int_t(low*nc), nu=Int_t(up*nc); //b.b. to take two lowest dEdX |
736 | // values from four ones choose | |
737 | // nu=2 | |
23efe5f1 | 738 | Float_t dedx=0; |
a9a2d814 | 739 | for (i=nl; i<nu; i++) dedx += fdEdxSample[i]; |
c0dd5278 | 740 | if (nu-nl>0) dedx /= (nu-nl); |
23efe5f1 | 741 | |
23efe5f1 | 742 | SetdEdx(dedx); |
743 | } | |
c7bafca9 | 744 | |
745 | Double_t AliITStrackV2:: | |
746 | PropagateToDCA(AliKalmanTrack *p, Double_t d, Double_t x0) { | |
747 | //-------------------------------------------------------------- | |
748 | // Propagates this track and the argument track to the position of the | |
749 | // distance of closest approach. | |
750 | // Returns the (weighed !) distance of closest approach. | |
751 | //-------------------------------------------------------------- | |
752 | Double_t xthis, xp, dca; | |
753 | { | |
754 | //Temporary solution | |
755 | Double_t b=1./GetLocalConvConst()/kB2C; | |
756 | AliExternalTrackParam dummy1(*this), dummy2(*p); | |
757 | dca=dummy1.GetDCA(&dummy2,b,xthis,xp); | |
758 | } | |
759 | if (!PropagateTo(xthis,d,x0)) { | |
760 | //AliWarning(" propagation failed !"); | |
761 | return 1e+33; | |
762 | } | |
763 | ||
764 | if (!p->PropagateTo(xp,d,x0)) { | |
765 | //AliWarning(" propagation failed !"; | |
766 | return 1e+33; | |
767 | } | |
768 | ||
769 | return dca; | |
770 | } | |
5773defd | 771 | |
772 | Double_t AliITStrackV2::Get1Pt() const { | |
773 | //-------------------------------------------------------------- | |
774 | // Returns the inverse Pt (1/GeV/c) | |
775 | // (or 1/"most probable pt", if the field is too weak) | |
776 | //-------------------------------------------------------------- | |
777 | if (TMath::Abs(GetLocalConvConst()) > kVeryBigConvConst) | |
778 | return 1./kMostProbableMomentum/TMath::Sqrt(1.+ GetTgl()*GetTgl()); | |
779 | return (TMath::Sign(1e-9,fP4) + fP4)*GetLocalConvConst(); | |
780 | } |