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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 TPC track class | |
18 | // | |
19 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch | |
20 | //----------------------------------------------------------------- | |
21 | ||
22 | #include <iostream.h> | |
23 | ||
24 | #include "AliCluster.h" | |
25 | #include "AliTPCtrack.h" | |
26 | #include "AliTPCcluster.h" | |
27 | #include "AliTPCClustersRow.h" | |
28 | #include "AliTPCClustersArray.h" | |
29 | ||
30 | ClassImp(AliTPCtrack) | |
31 | //_________________________________________________________________________ | |
32 | AliTPCtrack::AliTPCtrack(UInt_t index, const Double_t xx[5], | |
33 | const Double_t cc[15], Double_t xref, Double_t alpha) : AliKalmanTrack() { | |
34 | //----------------------------------------------------------------- | |
35 | // This is the main track constructor. | |
36 | //----------------------------------------------------------------- | |
37 | fdEdx=0.; | |
38 | ||
39 | fAlpha=alpha; | |
40 | fX=xref; | |
41 | ||
42 | fP0=xx[0]; fP1=xx[1]; fP2=xx[2]; fP3=xx[3]; fP4=xx[4]; | |
43 | ||
44 | fC00=cc[0]; | |
45 | fC10=cc[1]; fC11=cc[2]; | |
46 | fC20=cc[3]; fC21=cc[4]; fC22=cc[5]; | |
47 | fC30=cc[6]; fC31=cc[7]; fC32=cc[8]; fC33=cc[9]; | |
48 | fC40=cc[10]; fC41=cc[11]; fC42=cc[12]; fC43=cc[13]; fC44=cc[14]; | |
49 | ||
50 | fIndex[fN++]=index; | |
51 | } | |
52 | ||
53 | //_____________________________________________________________________________ | |
54 | AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) : AliKalmanTrack(t) { | |
55 | //----------------------------------------------------------------- | |
56 | // This is a track copy constructor. | |
57 | //----------------------------------------------------------------- | |
58 | for (Int_t i=0; i<fN; i++) fIndex[i]=t.fIndex[i]; | |
59 | ||
60 | fdEdx=t.fdEdx; | |
61 | ||
62 | fAlpha=t.fAlpha; | |
63 | fX=t.fX; | |
64 | } | |
65 | ||
66 | //_____________________________________________________________________________ | |
67 | Int_t AliTPCtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho,Double_t pm) | |
68 | { | |
69 | //----------------------------------------------------------------- | |
70 | // This function propagates a track to a reference plane x=xk. | |
71 | //----------------------------------------------------------------- | |
72 | if (TMath::Abs(fP3*xk - fP2) >= 0.99999) { | |
73 | if (fN>4) cerr<<fN<<" AliTPCtrack warning: Propagation failed !\n"; | |
74 | return 0; | |
75 | } | |
76 | ||
77 | Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fP0, z1=fP1; | |
78 | Double_t c1=fP3*x1 - fP2, r1=sqrt(1.- c1*c1); | |
79 | Double_t c2=fP3*x2 - fP2, r2=sqrt(1.- c2*c2); | |
80 | ||
81 | fP0 += dx*(c1+c2)/(r1+r2); | |
82 | fP1 += dx*(c1+c2)/(c1*r2 + c2*r1)*fP4; | |
83 | ||
84 | //f = F - 1 | |
85 | Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2; | |
86 | Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr); | |
87 | Double_t f03= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr); | |
88 | Double_t cr=c1*r2+c2*r1; | |
89 | Double_t f12=-dx*fP4*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr); | |
90 | Double_t f13=dx*fP4*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr); | |
91 | Double_t f14= dx*cc/cr; | |
92 | ||
93 | //b = C*ft | |
94 | Double_t b00=f02*fC20 + f03*fC30, b01=f12*fC20 + f13*fC30 + f14*fC40; | |
95 | Double_t b10=f02*fC21 + f03*fC31, b11=f12*fC21 + f13*fC31 + f14*fC41; | |
96 | Double_t b20=f02*fC22 + f03*fC32, b21=f12*fC22 + f13*fC32 + f14*fC42; | |
97 | Double_t b30=f02*fC32 + f03*fC33, b31=f12*fC32 + f13*fC33 + f14*fC43; | |
98 | Double_t b40=f02*fC42 + f03*fC43, b41=f12*fC42 + f13*fC43 + f14*fC44; | |
99 | ||
100 | //a = f*b = f*C*ft | |
101 | Double_t a00=f02*b20+f03*b30,a01=f02*b21+f03*b31,a11=f12*b21+f13*b31+f14*b41; | |
102 | ||
103 | //F*C*Ft = C + (a + b + bt) | |
104 | fC00 += a00 + 2*b00; | |
105 | fC10 += a01 + b01 + b10; | |
106 | fC20 += b20; | |
107 | fC30 += b30; | |
108 | fC40 += b40; | |
109 | fC11 += a11 + 2*b11; | |
110 | fC21 += b21; | |
111 | fC31 += b31; | |
112 | fC41 += b41; | |
113 | ||
114 | fX=x2; | |
115 | ||
116 | //Multiple scattering****************** | |
117 | Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fP0)*(y1-fP0)+(z1-fP1)*(z1-fP1)); | |
118 | Double_t p2=GetP()*GetP(); | |
119 | Double_t beta2=p2/(p2 + pm*pm); | |
120 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho/2.; | |
121 | //Double_t theta2=1.0259e-6*10*10/20/(beta2*p2)*d*rho; | |
122 | ||
123 | Double_t ey=fP3*fX - fP2, ez=fP4; | |
124 | Double_t xz=fP3*ez, zz1=ez*ez+1, xy=fP2+ey; | |
125 | ||
126 | fC33 += xz*xz*theta2; | |
127 | fC32 += xz*ez*xy*theta2; | |
128 | fC43 += xz*zz1*theta2; | |
129 | fC22 += (2*ey*ez*ez*fP2+1-ey*ey+ez*ez+fP2*fP2*ez*ez)*theta2; | |
130 | fC42 += ez*zz1*xy*theta2; | |
131 | fC44 += zz1*zz1*theta2; | |
132 | ||
133 | //Energy losses************************ | |
134 | Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho; | |
135 | if (x1 < x2) dE=-dE; | |
136 | cc=fP3; | |
137 | fP3*=(1.- sqrt(p2+pm*pm)/p2*dE); | |
138 | fP2+=fX*(fP3-cc); | |
139 | ||
140 | return 1; | |
141 | } | |
142 | ||
143 | //_____________________________________________________________________________ | |
144 | Int_t AliTPCtrack::PropagateToVertex(Double_t x0,Double_t rho,Double_t pm) | |
145 | { | |
146 | //----------------------------------------------------------------- | |
147 | // This function propagates tracks to the "vertex". | |
148 | //----------------------------------------------------------------- | |
149 | Double_t c=fP3*fX - fP2; | |
150 | Double_t tgf=-fP2/(fP3*fP0 + sqrt(1-c*c)); | |
151 | Double_t snf=tgf/sqrt(1.+ tgf*tgf); | |
152 | Double_t xv=(fP2+snf)/fP3; | |
153 | return PropagateTo(xv,x0,rho,pm); | |
154 | } | |
155 | ||
156 | //_____________________________________________________________________________ | |
157 | void AliTPCtrack::Update(const AliCluster *c, Double_t chisq, UInt_t index) | |
158 | { | |
159 | //----------------------------------------------------------------- | |
160 | // This function associates a cluster with this track. | |
161 | //----------------------------------------------------------------- | |
162 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
163 | r00+=fC00; r01+=fC10; r11+=fC11; | |
164 | Double_t det=r00*r11 - r01*r01; | |
165 | Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det; | |
166 | ||
167 | Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11; | |
168 | Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11; | |
169 | Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11; | |
170 | Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11; | |
171 | Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11; | |
172 | ||
173 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; | |
174 | Double_t cur=fP3 + k30*dy + k31*dz, eta=fP2 + k20*dy + k21*dz; | |
175 | if (TMath::Abs(cur*fX-eta) >= 0.99999) { | |
176 | if (fN>4) cerr<<fN<<" AliTPCtrack warning: Filtering failed !\n"; | |
177 | return; | |
178 | } | |
179 | ||
180 | fP0 += k00*dy + k01*dz; | |
181 | fP1 += k10*dy + k11*dz; | |
182 | fP2 = eta; | |
183 | fP3 = cur; | |
184 | fP4 += k40*dy + k41*dz; | |
185 | ||
186 | Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40; | |
187 | Double_t c12=fC21, c13=fC31, c14=fC41; | |
188 | ||
189 | fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11; | |
190 | fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13; | |
191 | fC40-=k00*c04+k01*c14; | |
192 | ||
193 | fC11-=k10*c01+k11*fC11; | |
194 | fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13; | |
195 | fC41-=k10*c04+k11*c14; | |
196 | ||
197 | fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13; | |
198 | fC42-=k20*c04+k21*c14; | |
199 | ||
200 | fC33-=k30*c03+k31*c13; | |
201 | fC43-=k30*c04+k31*c14; | |
202 | ||
203 | fC44-=k40*c04+k41*c14; | |
204 | ||
205 | fIndex[fN++]=index; | |
206 | fChi2 += chisq; | |
207 | } | |
208 | ||
209 | //_____________________________________________________________________________ | |
210 | Int_t AliTPCtrack::Rotate(Double_t alpha) | |
211 | { | |
212 | //----------------------------------------------------------------- | |
213 | // This function rotates this track. | |
214 | //----------------------------------------------------------------- | |
215 | fAlpha += alpha; | |
216 | ||
217 | Double_t x1=fX, y1=fP0; | |
218 | Double_t ca=cos(alpha), sa=sin(alpha); | |
219 | Double_t r1=fP3*fX - fP2; | |
220 | ||
221 | fX = x1*ca + y1*sa; | |
222 | fP0=-x1*sa + y1*ca; | |
223 | fP2=fP2*ca + (fP3*y1 + sqrt(1.- r1*r1))*sa; | |
224 | ||
225 | Double_t r2=fP3*fX - fP2; | |
226 | if (TMath::Abs(r2) >= 0.99999) { | |
227 | if (fN>4) cerr<<fN<<" AliTPCtrack warning: Rotation failed !\n"; | |
228 | return 0; | |
229 | } | |
230 | ||
231 | Double_t y0=fP0 + sqrt(1.- r2*r2)/fP3; | |
232 | if ((fP0-y0)*fP3 >= 0.) { | |
233 | if (fN>4) cerr<<fN<<" AliTPCtrack warning: Rotation failed !!!\n"; | |
234 | return 0; | |
235 | } | |
236 | ||
237 | //f = F - 1 | |
238 | Double_t f00=ca-1, f23=(y1 - r1*x1/sqrt(1.- r1*r1))*sa, | |
239 | f20=fP3*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1; | |
240 | ||
241 | //b = C*ft | |
242 | Double_t b00=fC00*f00, b02=fC00*f20+fC30*f23+fC20*f22; | |
243 | Double_t b10=fC10*f00, b12=fC10*f20+fC31*f23+fC21*f22; | |
244 | Double_t b20=fC20*f00, b22=fC20*f20+fC32*f23+fC22*f22; | |
245 | Double_t b30=fC30*f00, b32=fC30*f20+fC33*f23+fC32*f22; | |
246 | Double_t b40=fC40*f00, b42=fC40*f20+fC43*f23+fC42*f22; | |
247 | ||
248 | //a = f*b = f*C*ft | |
249 | Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f23*b32+f22*b22; | |
250 | ||
251 | // *** Double_t dy2=fCyy; | |
252 | ||
253 | //F*C*Ft = C + (a + b + bt) | |
254 | fC00 += a00 + 2*b00; | |
255 | fC10 += b10; | |
256 | fC20 += a02+b20+b02; | |
257 | fC30 += b30; | |
258 | fC40 += b40; | |
259 | fC21 += b12; | |
260 | fC32 += b32; | |
261 | fC22 += a22 + 2*b22; | |
262 | fC42 += b42; | |
263 | ||
264 | // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1); | |
265 | // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1); | |
266 | ||
267 | return 1; | |
268 | } | |
269 | ||
270 | //_____________________________________________________________________________ | |
271 | void AliTPCtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const | |
272 | { | |
273 | //----------------------------------------------------------------- | |
274 | // This function returns reconstructed track momentum in the global system. | |
275 | //----------------------------------------------------------------- | |
276 | Double_t pt=TMath::Abs(GetPt()); // GeV/c | |
277 | Double_t r=fP3*fX-fP2; | |
278 | Double_t y0=fP0 + sqrt(1.- r*r)/fP3; | |
279 | px=-pt*(fP0-y0)*fP3; //cos(phi); | |
280 | py=-pt*(fP2-fX *fP3); //sin(phi); | |
281 | pz=pt*fP4; | |
282 | Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha); | |
283 | py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha); | |
284 | px=tmp; | |
285 | } | |
286 | ||
287 | //_____________________________________________________________________________ | |
288 | void AliTPCtrack::CookLabel(AliTPCClustersArray *ca) { | |
289 | //----------------------------------------------------------------- | |
290 | // This function cooks the track label. If label<0, this track is fake. | |
291 | //----------------------------------------------------------------- | |
292 | Int_t *lb=new Int_t[fN]; | |
293 | Int_t *mx=new Int_t[fN]; | |
294 | AliTPCcluster **clusters=new AliTPCcluster*[fN]; | |
295 | ||
296 | Int_t i; | |
297 | Int_t sec,row,ncl; | |
298 | for (i=0; i<fN; i++) { | |
299 | lb[i]=mx[i]=0; | |
300 | GetCluster(i,sec,row,ncl); | |
301 | AliTPCClustersRow *clrow=ca->GetRow(sec,row); | |
302 | clusters[i]=(AliTPCcluster*)(*clrow)[ncl]; | |
303 | } | |
304 | ||
305 | Int_t lab=123456789; | |
306 | for (i=0; i<fN; i++) { | |
307 | AliTPCcluster *c=clusters[i]; | |
308 | lab=TMath::Abs(c->GetLabel(0)); | |
309 | Int_t j; | |
310 | for (j=0; j<fN; j++) | |
311 | if (lb[j]==lab || mx[j]==0) break; | |
312 | lb[j]=lab; | |
313 | (mx[j])++; | |
314 | } | |
315 | ||
316 | Int_t max=0; | |
317 | for (i=0; i<fN; i++) | |
318 | if (mx[i]>max) {max=mx[i]; lab=lb[i];} | |
319 | ||
320 | for (i=0; i<fN; i++) { | |
321 | AliTPCcluster *c=clusters[i]; | |
322 | if (TMath::Abs(c->GetLabel(1)) == lab || | |
323 | TMath::Abs(c->GetLabel(2)) == lab ) max++; | |
324 | } | |
325 | ||
326 | SetLabel(-lab); | |
327 | if (1.-Float_t(max)/fN <= 0.10) { | |
328 | //Int_t tail=Int_t(0.08*fN); | |
329 | Int_t tail=14; | |
330 | max=0; | |
331 | for (i=1; i<=tail; i++) { | |
332 | AliTPCcluster *c=clusters[fN-i]; | |
333 | if (lab == TMath::Abs(c->GetLabel(0)) || | |
334 | lab == TMath::Abs(c->GetLabel(1)) || | |
335 | lab == TMath::Abs(c->GetLabel(2))) max++; | |
336 | } | |
337 | if (max >= Int_t(0.5*tail)) SetLabel(lab); | |
338 | } | |
339 | ||
340 | delete[] lb; | |
341 | delete[] mx; | |
342 | delete[] clusters; | |
343 | } |