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73042f01 | 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 | ||
73042f01 | 16 | //----------------------------------------------------------------- |
17 | // Implementation of the TPC track class | |
18 | // | |
19 | // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch | |
20 | //----------------------------------------------------------------- | |
21 | ||
b19a0509 | 22 | #include <iostream.h> |
23 | ||
73042f01 | 24 | #include "AliTPCtrack.h" |
25 | #include "AliTPCcluster.h" | |
26 | #include "AliTPCClustersRow.h" | |
27 | #include "AliTPCClustersArray.h" | |
28 | ||
29 | ClassImp(AliTPCtrack) | |
b9de75e1 | 30 | |
73042f01 | 31 | //_________________________________________________________________________ |
32 | AliTPCtrack::AliTPCtrack(UInt_t index, const Double_t xx[5], | |
b19a0509 | 33 | const Double_t cc[15], Double_t xref, Double_t alpha) : AliKalmanTrack() { |
73042f01 | 34 | //----------------------------------------------------------------- |
35 | // This is the main track constructor. | |
36 | //----------------------------------------------------------------- | |
73042f01 | 37 | fX=xref; |
be9c5115 | 38 | fAlpha=alpha; |
39 | if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi(); | |
40 | if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi(); | |
41 | fdEdx=0.; | |
73042f01 | 42 | |
b19a0509 | 43 | fP0=xx[0]; fP1=xx[1]; fP2=xx[2]; fP3=xx[3]; fP4=xx[4]; |
73042f01 | 44 | |
b19a0509 | 45 | fC00=cc[0]; |
46 | fC10=cc[1]; fC11=cc[2]; | |
47 | fC20=cc[3]; fC21=cc[4]; fC22=cc[5]; | |
48 | fC30=cc[6]; fC31=cc[7]; fC32=cc[8]; fC33=cc[9]; | |
49 | fC40=cc[10]; fC41=cc[11]; fC42=cc[12]; fC43=cc[13]; fC44=cc[14]; | |
73042f01 | 50 | |
be9c5115 | 51 | fIndex[0]=index; |
52 | SetNumberOfClusters(1); | |
b9de75e1 | 53 | |
54 | } | |
55 | ||
56 | //_____________________________________________________________________________ | |
57 | AliTPCtrack::AliTPCtrack(const AliKalmanTrack& t,Double_t alpha) { | |
58 | //----------------------------------------------------------------- | |
59 | // Conversion AliKalmanTrack -> AliTPCtrack. | |
60 | //----------------------------------------------------------------- | |
61 | SetLabel(t.GetLabel()); | |
62 | SetChi2(0.); | |
7f6ddf58 | 63 | SetMass(t.GetMass()); |
b9de75e1 | 64 | SetNumberOfClusters(0); |
65 | //SetConvConst(t.GetConvConst()); | |
66 | ||
67 | fdEdx = 0.; | |
68 | fAlpha = alpha; | |
69 | if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi(); | |
70 | else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi(); | |
71 | ||
72 | //Conversion of the track parameters | |
73 | Double_t x,p[5]; t.GetExternalParameters(x,p); | |
74 | fX=x; x=GetConvConst(); | |
75 | fP0=p[0]; | |
76 | fP1=p[1]; | |
77 | fP3=p[3]; | |
78 | fP4=p[4]/x; | |
79 | fP2=fP4*fX - p[2]; | |
80 | ||
81 | //Conversion of the covariance matrix | |
82 | Double_t c[15]; t.GetExternalCovariance(c); | |
83 | c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x; | |
84 | ||
85 | Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5]; | |
86 | Double_t c32=fX*c[13] - c[8]; | |
87 | Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12]; | |
88 | ||
89 | fC00=c[0 ]; | |
90 | fC10=c[1 ]; fC11=c[2 ]; | |
91 | fC20=c20; fC21=c21; fC22=c22; | |
92 | fC30=c[6 ]; fC31=c[7 ]; fC32=c32; fC33=c[9 ]; | |
93 | fC40=c[10]; fC41=c[11]; fC42=c42; fC43=c[13]; fC44=c[14]; | |
94 | ||
73042f01 | 95 | } |
96 | ||
97 | //_____________________________________________________________________________ | |
b19a0509 | 98 | AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) : AliKalmanTrack(t) { |
73042f01 | 99 | //----------------------------------------------------------------- |
100 | // This is a track copy constructor. | |
101 | //----------------------------------------------------------------- | |
be9c5115 | 102 | fX=t.fX; |
103 | fAlpha=t.fAlpha; | |
73042f01 | 104 | fdEdx=t.fdEdx; |
105 | ||
be9c5115 | 106 | fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4; |
107 | ||
108 | fC00=t.fC00; | |
109 | fC10=t.fC10; fC11=t.fC11; | |
110 | fC20=t.fC20; fC21=t.fC21; fC22=t.fC22; | |
111 | fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33; | |
112 | fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44; | |
113 | ||
114 | Int_t n=GetNumberOfClusters(); | |
115 | for (Int_t i=0; i<n; i++) fIndex[i]=t.fIndex[i]; | |
116 | } | |
117 | ||
118 | //_____________________________________________________________________________ | |
119 | Int_t AliTPCtrack::Compare(const TObject *o) const { | |
120 | //----------------------------------------------------------------- | |
121 | // This function compares tracks according to the their curvature | |
122 | //----------------------------------------------------------------- | |
123 | AliTPCtrack *t=(AliTPCtrack*)o; | |
124 | Double_t co=TMath::Abs(t->Get1Pt()); | |
125 | Double_t c =TMath::Abs(Get1Pt()); | |
126 | if (c>co) return 1; | |
127 | else if (c<co) return -1; | |
128 | return 0; | |
129 | } | |
130 | ||
131 | //_____________________________________________________________________________ | |
132 | void AliTPCtrack::GetExternalCovariance(Double_t cc[15]) const { | |
133 | //------------------------------------------------------------------------- | |
134 | // This function returns an external representation of the covriance matrix. | |
135 | // (See comments in AliTPCtrack.h about external track representation) | |
136 | //------------------------------------------------------------------------- | |
9b280d80 | 137 | Double_t a=GetConvConst(); |
be9c5115 | 138 | |
b9de75e1 | 139 | Double_t c22=fX*fX*fC44-2*fX*fC42+fC22; |
140 | Double_t c32=fX*fC43-fC32; | |
141 | Double_t c20=fX*fC40-fC20, c21=fX*fC41-fC21, c42=fX*fC44-fC42; | |
be9c5115 | 142 | |
143 | cc[0 ]=fC00; | |
144 | cc[1 ]=fC10; cc[2 ]=fC11; | |
145 | cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22; | |
b9de75e1 | 146 | cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=c32; cc[9 ]=fC33; |
147 | cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=c42*a; cc[13]=fC43*a; cc[14]=fC44*a*a; | |
be9c5115 | 148 | |
149 | } | |
150 | ||
151 | //_____________________________________________________________________________ | |
152 | Double_t AliTPCtrack::GetPredictedChi2(const AliCluster *c) const | |
153 | { | |
154 | //----------------------------------------------------------------- | |
155 | // This function calculates a predicted chi2 increment. | |
156 | //----------------------------------------------------------------- | |
157 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
158 | r00+=fC00; r01+=fC10; r11+=fC11; | |
159 | ||
160 | Double_t det=r00*r11 - r01*r01; | |
161 | if (TMath::Abs(det) < 1.e-10) { | |
162 | Int_t n=GetNumberOfClusters(); | |
163 | if (n>4) cerr<<n<<" AliKalmanTrack warning: Singular matrix !\n"; | |
164 | return 1e10; | |
165 | } | |
166 | Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01; | |
167 | ||
168 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; | |
169 | ||
170 | return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det; | |
73042f01 | 171 | } |
172 | ||
173 | //_____________________________________________________________________________ | |
7f6ddf58 | 174 | Int_t AliTPCtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho) { |
73042f01 | 175 | //----------------------------------------------------------------- |
176 | // This function propagates a track to a reference plane x=xk. | |
177 | //----------------------------------------------------------------- | |
b9de75e1 | 178 | if (TMath::Abs(fP4*xk - fP2) >= 0.99999) { |
be9c5115 | 179 | Int_t n=GetNumberOfClusters(); |
180 | if (n>4) cerr<<n<<" AliTPCtrack warning: Propagation failed !\n"; | |
73042f01 | 181 | return 0; |
182 | } | |
183 | ||
b19a0509 | 184 | Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fP0, z1=fP1; |
b9de75e1 | 185 | Double_t c1=fP4*x1 - fP2, r1=sqrt(1.- c1*c1); |
186 | Double_t c2=fP4*x2 - fP2, r2=sqrt(1.- c2*c2); | |
73042f01 | 187 | |
b19a0509 | 188 | fP0 += dx*(c1+c2)/(r1+r2); |
b9de75e1 | 189 | fP1 += dx*(c1+c2)/(c1*r2 + c2*r1)*fP3; |
73042f01 | 190 | |
191 | //f = F - 1 | |
192 | Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2; | |
b19a0509 | 193 | Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr); |
b9de75e1 | 194 | Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr); |
73042f01 | 195 | Double_t cr=c1*r2+c2*r1; |
b9de75e1 | 196 | Double_t f12=-dx*fP3*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr); |
197 | Double_t f13= dx*cc/cr; | |
198 | Double_t f14=dx*fP3*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr); | |
73042f01 | 199 | |
200 | //b = C*ft | |
b9de75e1 | 201 | Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30; |
202 | Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31; | |
203 | Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32; | |
204 | Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33; | |
205 | Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43; | |
73042f01 | 206 | |
207 | //a = f*b = f*C*ft | |
b9de75e1 | 208 | Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31; |
73042f01 | 209 | |
210 | //F*C*Ft = C + (a + b + bt) | |
b19a0509 | 211 | fC00 += a00 + 2*b00; |
212 | fC10 += a01 + b01 + b10; | |
213 | fC20 += b20; | |
214 | fC30 += b30; | |
215 | fC40 += b40; | |
216 | fC11 += a11 + 2*b11; | |
217 | fC21 += b21; | |
218 | fC31 += b31; | |
219 | fC41 += b41; | |
73042f01 | 220 | |
221 | fX=x2; | |
222 | ||
223 | //Multiple scattering****************** | |
b19a0509 | 224 | Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fP0)*(y1-fP0)+(z1-fP1)*(z1-fP1)); |
be9c5115 | 225 | Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt()); |
7f6ddf58 | 226 | Double_t beta2=p2/(p2 + GetMass()*GetMass()); |
be9c5115 | 227 | Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho; |
b19a0509 | 228 | //Double_t theta2=1.0259e-6*10*10/20/(beta2*p2)*d*rho; |
73042f01 | 229 | |
b9de75e1 | 230 | Double_t ey=fP4*fX - fP2, ez=fP3; |
231 | Double_t xz=fP4*ez, zz1=ez*ez+1, xy=fP2+ey; | |
73042f01 | 232 | |
b19a0509 | 233 | fC22 += (2*ey*ez*ez*fP2+1-ey*ey+ez*ez+fP2*fP2*ez*ez)*theta2; |
b9de75e1 | 234 | fC32 += ez*zz1*xy*theta2; |
235 | fC33 += zz1*zz1*theta2; | |
236 | fC42 += xz*ez*xy*theta2; | |
237 | fC43 += xz*zz1*theta2; | |
238 | fC44 += xz*xz*theta2; | |
73042f01 | 239 | |
240 | //Energy losses************************ | |
241 | Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho; | |
242 | if (x1 < x2) dE=-dE; | |
b9de75e1 | 243 | cc=fP4; |
7f6ddf58 | 244 | fP4*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE); |
b9de75e1 | 245 | fP2+=fX*(fP4-cc); |
73042f01 | 246 | |
247 | return 1; | |
248 | } | |
249 | ||
250 | //_____________________________________________________________________________ | |
7f6ddf58 | 251 | Int_t AliTPCtrack::PropagateToVertex(Double_t x0,Double_t rho) |
73042f01 | 252 | { |
253 | //----------------------------------------------------------------- | |
254 | // This function propagates tracks to the "vertex". | |
255 | //----------------------------------------------------------------- | |
b9de75e1 | 256 | Double_t c=fP4*fX - fP2; |
257 | Double_t tgf=-fP2/(fP4*fP0 + sqrt(1-c*c)); | |
73042f01 | 258 | Double_t snf=tgf/sqrt(1.+ tgf*tgf); |
b9de75e1 | 259 | Double_t xv=(fP2+snf)/fP4; |
7f6ddf58 | 260 | return PropagateTo(xv,x0,rho); |
73042f01 | 261 | } |
262 | ||
263 | //_____________________________________________________________________________ | |
be9c5115 | 264 | Int_t AliTPCtrack::Update(const AliCluster *c, Double_t chisq, UInt_t index) { |
73042f01 | 265 | //----------------------------------------------------------------- |
266 | // This function associates a cluster with this track. | |
267 | //----------------------------------------------------------------- | |
268 | Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2(); | |
b19a0509 | 269 | r00+=fC00; r01+=fC10; r11+=fC11; |
73042f01 | 270 | Double_t det=r00*r11 - r01*r01; |
271 | Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det; | |
272 | ||
b19a0509 | 273 | Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11; |
274 | Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11; | |
275 | Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11; | |
276 | Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11; | |
277 | Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11; | |
73042f01 | 278 | |
b19a0509 | 279 | Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1; |
b9de75e1 | 280 | Double_t cur=fP4 + k40*dy + k41*dz, eta=fP2 + k20*dy + k21*dz; |
73042f01 | 281 | if (TMath::Abs(cur*fX-eta) >= 0.99999) { |
be9c5115 | 282 | Int_t n=GetNumberOfClusters(); |
283 | if (n>4) cerr<<n<<" AliTPCtrack warning: Filtering failed !\n"; | |
284 | return 0; | |
73042f01 | 285 | } |
286 | ||
b19a0509 | 287 | fP0 += k00*dy + k01*dz; |
288 | fP1 += k10*dy + k11*dz; | |
289 | fP2 = eta; | |
b9de75e1 | 290 | fP3 += k30*dy + k31*dz; |
291 | fP4 = cur; | |
73042f01 | 292 | |
b19a0509 | 293 | Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40; |
294 | Double_t c12=fC21, c13=fC31, c14=fC41; | |
73042f01 | 295 | |
b19a0509 | 296 | fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11; |
297 | fC20-=k00*c02+k01*c12; fC30-=k00*c03+k01*c13; | |
298 | fC40-=k00*c04+k01*c14; | |
73042f01 | 299 | |
b19a0509 | 300 | fC11-=k10*c01+k11*fC11; |
301 | fC21-=k10*c02+k11*c12; fC31-=k10*c03+k11*c13; | |
302 | fC41-=k10*c04+k11*c14; | |
73042f01 | 303 | |
b19a0509 | 304 | fC22-=k20*c02+k21*c12; fC32-=k20*c03+k21*c13; |
305 | fC42-=k20*c04+k21*c14; | |
73042f01 | 306 | |
b19a0509 | 307 | fC33-=k30*c03+k31*c13; |
b9de75e1 | 308 | fC43-=k40*c03+k41*c13; |
73042f01 | 309 | |
b19a0509 | 310 | fC44-=k40*c04+k41*c14; |
73042f01 | 311 | |
be9c5115 | 312 | Int_t n=GetNumberOfClusters(); |
313 | fIndex[n]=index; | |
314 | SetNumberOfClusters(n+1); | |
315 | SetChi2(GetChi2()+chisq); | |
316 | ||
317 | return 1; | |
73042f01 | 318 | } |
319 | ||
320 | //_____________________________________________________________________________ | |
321 | Int_t AliTPCtrack::Rotate(Double_t alpha) | |
322 | { | |
323 | //----------------------------------------------------------------- | |
324 | // This function rotates this track. | |
325 | //----------------------------------------------------------------- | |
326 | fAlpha += alpha; | |
be9c5115 | 327 | if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi(); |
328 | if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi(); | |
73042f01 | 329 | |
b19a0509 | 330 | Double_t x1=fX, y1=fP0; |
73042f01 | 331 | Double_t ca=cos(alpha), sa=sin(alpha); |
b9de75e1 | 332 | Double_t r1=fP4*fX - fP2; |
73042f01 | 333 | |
334 | fX = x1*ca + y1*sa; | |
b19a0509 | 335 | fP0=-x1*sa + y1*ca; |
b9de75e1 | 336 | fP2=fP2*ca + (fP4*y1 + sqrt(1.- r1*r1))*sa; |
73042f01 | 337 | |
b9de75e1 | 338 | Double_t r2=fP4*fX - fP2; |
73042f01 | 339 | if (TMath::Abs(r2) >= 0.99999) { |
be9c5115 | 340 | Int_t n=GetNumberOfClusters(); |
341 | if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !\n"; | |
73042f01 | 342 | return 0; |
343 | } | |
344 | ||
b9de75e1 | 345 | Double_t y0=fP0 + sqrt(1.- r2*r2)/fP4; |
346 | if ((fP0-y0)*fP4 >= 0.) { | |
be9c5115 | 347 | Int_t n=GetNumberOfClusters(); |
348 | if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !!!\n"; | |
73042f01 | 349 | return 0; |
350 | } | |
351 | ||
352 | //f = F - 1 | |
b9de75e1 | 353 | Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa, |
354 | f20=fP4*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1; | |
73042f01 | 355 | |
356 | //b = C*ft | |
b9de75e1 | 357 | Double_t b00=fC00*f00, b02=fC00*f20+fC40*f24+fC20*f22; |
358 | Double_t b10=fC10*f00, b12=fC10*f20+fC41*f24+fC21*f22; | |
359 | Double_t b20=fC20*f00, b22=fC20*f20+fC42*f24+fC22*f22; | |
360 | Double_t b30=fC30*f00, b32=fC30*f20+fC43*f24+fC32*f22; | |
361 | Double_t b40=fC40*f00, b42=fC40*f20+fC44*f24+fC42*f22; | |
73042f01 | 362 | |
363 | //a = f*b = f*C*ft | |
b9de75e1 | 364 | Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22; |
73042f01 | 365 | |
366 | // *** Double_t dy2=fCyy; | |
367 | ||
368 | //F*C*Ft = C + (a + b + bt) | |
b19a0509 | 369 | fC00 += a00 + 2*b00; |
370 | fC10 += b10; | |
371 | fC20 += a02+b20+b02; | |
372 | fC30 += b30; | |
373 | fC40 += b40; | |
374 | fC21 += b12; | |
375 | fC32 += b32; | |
376 | fC22 += a22 + 2*b22; | |
377 | fC42 += b42; | |
73042f01 | 378 | |
379 | // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1); | |
380 | // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1); | |
381 | ||
382 | return 1; | |
383 | } | |
384 | ||
b9de75e1 | 385 | void AliTPCtrack::ResetCovariance() { |
386 | //------------------------------------------------------------------ | |
387 | //This function makes a track forget its history :) | |
388 | //------------------------------------------------------------------ | |
389 | ||
390 | fC00*=10.; | |
391 | fC10=0.; fC11*=10.; | |
392 | fC20=0.; fC21=0.; fC22*=10.; | |
393 | fC30=0.; fC31=0.; fC32=0.; fC33*=10.; | |
394 | fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.; | |
395 | ||
73042f01 | 396 | } |