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3acc14d5 1/**************************************************************************
2 * Copyright(c) 1998-2007, 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#include <TClonesArray.h>
308c2f7c 17#include <TTree.h>
3acc14d5 18#include "AliLog.h"
19#include "AliESDVertex.h"
0333e459 20#include "AliITSgeomTGeo.h"
3acc14d5 21#include "AliITSRecPoint.h"
81ba01de 22#include "AliITSReconstructor.h"
3acc14d5 23#include "AliITSVertexerCosmics.h"
24#include "AliStrLine.h"
25
26//------------------------------------------------------------------------
27// This class implements a method to construct a "fake" primary
b8ed1a92 28// vertex for cosmic events in which the muon crosses one of 5 inner
29// ITS layers. A fake primary vertex is needed for the reconstruction,
3acc14d5 30// with e.g. AliITStrackerSA, of the two tracks produced by the muon
31// in the ITS.
b8ed1a92 32// We build pairs of clusters on a given layer and define the fake vertex as
3acc14d5 33// the mid-point of the straight line joining the two clusters.
b8ed1a92 34// We use the innermost layer that has at least two clusters.
35// We reject the background by requiring at least one cluster on the outer
36// layer, closer than fMaxDistOnOuterLayer to the tracklet prolongation.
3acc14d5 37// We can reject (potentially pathological) events with the muon track
b8ed1a92 38// tangential to the layer by the requiring the radial position of
3acc14d5 39// the vertex to be smaller than fMaxVtxRadius.
40// Due to background clusters, more than one vertex per event can
41// be found. We consider the first found.
b8ed1a92 42// The errors on x,y,z of the vertex are calculated as errors on the mean
43// of clusters coordinates. Non-diag elements of vertex cov. mat. are set to 0.
3acc14d5 44// The number of contributors set in the AliESDVertex object is the
b8ed1a92 45// number of the layer on which the tracklet was built; if this number is -1,
3acc14d5 46// the procedure could not find a vertex position and by default
47// the vertex coordinates are set to (0,0,0) with large errors (100,100,100)
3acc14d5 48//
49// Origin: A.Dainese, andrea.dainese@lnl.infn.it
50//-------------------------------------------------------------------------
51
52ClassImp(AliITSVertexerCosmics)
53
54//-------------------------------------------------------------------------
55AliITSVertexerCosmics::AliITSVertexerCosmics():AliITSVertexer(),
b8ed1a92 56fMaxDistOnOuterLayer(0),
3acc14d5 57fMinDist2Vtxs(0)
58{
59 // Default constructor
b8ed1a92 60 SetFirstLastModules(0,0,79);
61 SetFirstLastModules(1,80,239);
62 SetFirstLastModules(2,240,323);
63 SetFirstLastModules(3,324,499);
64 SetFirstLastModules(4,500,1247);
65 SetFirstLastModules(5,1248,2197);
7e33c4e6 66 /*
b8ed1a92 67 SetMaxVtxRadius(0,3.5);
68 SetMaxVtxRadius(1,6.5);
69 SetMaxVtxRadius(2,14.5);
70 SetMaxVtxRadius(3,23.5);
71 SetMaxVtxRadius(4,37.5);
72 SetMaxVtxRadius(5,42.5);
7e33c4e6 73 */
81ba01de 74 SetMaxVtxRadius(0,5.5);
75 SetMaxVtxRadius(1,8.5);
76 SetMaxVtxRadius(2,18.5);
77 SetMaxVtxRadius(3,28.5);
78 SetMaxVtxRadius(4,39.5);
79 SetMaxVtxRadius(5,48.5);
7e33c4e6 80
b8ed1a92 81 SetMaxDistOnOuterLayer();
3acc14d5 82 SetMinDist2Vtxs();
83}
84//--------------------------------------------------------------------------
308c2f7c 85AliESDVertex* AliITSVertexerCosmics::FindVertexForCurrentEvent(TTree *itsClusterTree)
3acc14d5 86{
87 // Defines the AliESDVertex for the current event
88
89 fCurrentVertex = 0;
3acc14d5 90
91 TClonesArray *recpoints=new TClonesArray("AliITSRecPoint",10000);
308c2f7c 92 itsClusterTree->SetBranchAddress("ITSRecPoints",&recpoints);
3acc14d5 93
3acc14d5 94 Int_t lay,lad,det;
95
81ba01de 96 Double_t pos[3]={0.,0.,0.};
97 Double_t err[3]={100.,100.,100.};
98 Int_t ncontributors = -1;
99
b8ed1a92 100 // Search for innermost layer with at least two clusters
101 // on two different modules
81ba01de 102 Int_t ilayer=0,ilayer2=0;
b8ed1a92 103 while(ilayer<6) {
81ba01de 104 if(AliITSReconstructor::GetRecoParam()->GetLayersToSkip(ilayer)) {
105 ilayer++;
106 continue;
107 }
b8ed1a92 108 Int_t nHitModules=0;
109 for(Int_t imodule=fFirst[ilayer]; imodule<=fLast[ilayer]; imodule++) {
308c2f7c 110 itsClusterTree->GetEvent(imodule);
b8ed1a92 111 AliITSgeomTGeo::GetModuleId(imodule,lay,lad,det);
112 lay -= 1; // AliITSgeomTGeo gives layer from 1 to 6, we want 0 to 5
113 if(lay!=ilayer) AliFatal("Layer mismatch!");
114 if(recpoints->GetEntriesFast()>0) nHitModules++;
115 }
116 if(nHitModules>=2) break;
117 ilayer++;
118 }
81ba01de 119
120 ilayer2=ilayer+1;
121 while(ilayer2<6) {
122 if(!AliITSReconstructor::GetRecoParam()->GetLayersToSkip(ilayer2)) break;
123 ilayer2++;
124 }
125
7e33c4e6 126 // try tracklet on SPD2 and point on SPD1
8403ece4 127 if(ilayer==1 && !AliITSReconstructor::GetRecoParam()->GetLayersToSkip(0)) {ilayer=0; ilayer2=1;}
81ba01de 128
129 if(ilayer>4 || ilayer2>5) {
130 AliWarning("Not enough clusters");
131 delete recpoints;
81ba01de 132 fCurrentVertex = new AliESDVertex(pos,err,"cosmics");
133 fCurrentVertex->SetTitle("cosmics fake vertex (failed)");
134 fCurrentVertex->SetNContributors(ncontributors);
135 return fCurrentVertex;
136 }
137
b8ed1a92 138
a1fca0e6 139 const Int_t arrSize = 1000;
140 Float_t xclInnLay[arrSize],yclInnLay[arrSize],zclInnLay[arrSize],modclInnLay[arrSize];
141 Float_t e2xclInnLay[arrSize],e2yclInnLay[arrSize],e2zclInnLay[arrSize];
81ba01de 142 Float_t e2xclOutLay[arrSize],e2yclOutLay[arrSize],e2zclOutLay[arrSize];
b8ed1a92 143 Int_t nclInnLayStored=0;
a1fca0e6 144 Float_t xclOutLay[arrSize],yclOutLay[arrSize],zclOutLay[arrSize],modclOutLay[arrSize];
b8ed1a92 145 Int_t nclOutLayStored=0;
146 Int_t nRecPoints,nRecPointsInnLay=0;
147
148 Float_t gc[3],gcov[5];
149
81ba01de 150 Float_t matchOutLayValue;
151 Float_t distxyInnLay,distxyInnLayBest=0.;
b8ed1a92 152 Double_t p1[3],p2[3],p3[3];
81ba01de 153
b8ed1a92 154 Float_t xvtx,yvtx,zvtx,rvtx;
81ba01de 155 Int_t i1InnLayBest=-1,i2InnLayBest=-1;
3acc14d5 156
b107ee21 157
b8ed1a92 158 // Collect clusters in the selected layer and the outer one
81ba01de 159 for(Int_t imodule=fFirst[ilayer]; imodule<=fLast[ilayer2]; imodule++) {
308c2f7c 160 itsClusterTree->GetEvent(imodule);
0333e459 161 AliITSgeomTGeo::GetModuleId(imodule,lay,lad,det);
b8ed1a92 162 lay -= 1; // AliITSgeomTGeo gives layer from 1 to 6, we want 0 to 5
163 nRecPoints=recpoints->GetEntriesFast();
164 if(imodule<=fLast[ilayer]) nRecPointsInnLay += nRecPoints;
165 //printf("cosmics: module %d clusters %d\n",imodule,nRecPoints);
166 for(Int_t irp=0; irp<nRecPoints; irp++) {
3acc14d5 167 AliITSRecPoint *rp=(AliITSRecPoint*)recpoints->UncheckedAt(irp);
168 // Local coordinates of this recpoint
b8ed1a92 169 rp->GetGlobalXYZ(gc);
170 if(lay==ilayer) { // store InnLay clusters
171 xclInnLay[nclInnLayStored]=gc[0];
172 yclInnLay[nclInnLayStored]=gc[1];
173 zclInnLay[nclInnLayStored]=gc[2];
174 rp->GetGlobalCov(gcov);
175 e2xclInnLay[nclInnLayStored]=gcov[0];
176 e2yclInnLay[nclInnLayStored]=gcov[3];
177 e2zclInnLay[nclInnLayStored]=gcov[5];
178 modclInnLay[nclInnLayStored]=imodule;
179 nclInnLayStored++;
3acc14d5 180 }
81ba01de 181 if(lay==ilayer2) { // store OutLay clusters
b8ed1a92 182 xclOutLay[nclOutLayStored]=gc[0];
183 yclOutLay[nclOutLayStored]=gc[1];
184 zclOutLay[nclOutLayStored]=gc[2];
81ba01de 185 rp->GetGlobalCov(gcov);
186 e2xclOutLay[nclOutLayStored]=gcov[0];
187 e2yclOutLay[nclOutLayStored]=gcov[3];
188 e2zclOutLay[nclOutLayStored]=gcov[5];
b8ed1a92 189 modclOutLay[nclOutLayStored]=imodule;
190 nclOutLayStored++;
3acc14d5 191 }
b107ee21 192 if(nclInnLayStored>arrSize || nclOutLayStored>arrSize) {
193 //AliFatal("More than arrSize clusters per layer");
194 AliWarning("Too many clusters per layer");
195 delete recpoints;
b107ee21 196 fCurrentVertex = new AliESDVertex(pos,err,"cosmics");
197 fCurrentVertex->SetTitle("cosmics fake vertex (failed)");
198 fCurrentVertex->SetNContributors(ncontributors);
199 return fCurrentVertex;
200 }
3acc14d5 201 }// end clusters in a module
b8ed1a92 202 }// end modules
3acc14d5 203
81ba01de 204
205 Int_t i1InnLay,i2InnLay,iOutLay;
206
3acc14d5 207 // build fake vertices
81ba01de 208 printf("Building tracklets on layer %d\n",ilayer);
209
b8ed1a92 210 // InnLay - first cluster
81ba01de 211 for(i1InnLay=0; i1InnLay<nclInnLayStored; i1InnLay++) {
b8ed1a92 212 p1[0]=xclInnLay[i1InnLay];
213 p1[1]=yclInnLay[i1InnLay];
214 p1[2]=zclInnLay[i1InnLay];
215 // InnLay - second cluster
81ba01de 216 for(i2InnLay=i1InnLay+1; i2InnLay<nclInnLayStored; i2InnLay++) {
b8ed1a92 217 if(modclInnLay[i1InnLay]==modclInnLay[i2InnLay]) continue;
218 p2[0]=xclInnLay[i2InnLay];
219 p2[1]=yclInnLay[i2InnLay];
220 p2[2]=zclInnLay[i2InnLay];
221 // look for point on OutLay
81ba01de 222 AliStrLine innLayline(p1,p2,kTRUE);
223 for(iOutLay=0; iOutLay<nclOutLayStored; iOutLay++) {
b8ed1a92 224 p3[0]=xclOutLay[iOutLay];
225 p3[1]=yclOutLay[iOutLay];
226 p3[2]=zclOutLay[iOutLay];
7e33c4e6 227 //printf("(%f,%f) (%f,%f) (%f,%f) %f\n",p1[0],p1[1],p2[0],p2[1],p3[0],p3[1],innLayline.GetDistFromPoint(p3));
81ba01de 228 matchOutLayValue=innLayline.GetDistFromPoint(p3);
229 distxyInnLay = (p1[0]-p2[0])*(p1[0]-p2[0])+(p1[1]-p2[1])*(p1[1]-p2[1]);
230 if(matchOutLayValue<fMaxDistOnOuterLayer &&
231 distxyInnLay>distxyInnLayBest) {
7e33c4e6 232 //printf("found\n");
81ba01de 233 distxyInnLayBest=distxyInnLay;
234 i1InnLayBest=i1InnLay;
235 i2InnLayBest=i2InnLay;
236 }
3acc14d5 237 }
b8ed1a92 238 } // InnLay - second cluster
239 } // InnLay - first cluster
3acc14d5 240
81ba01de 241 if(i1InnLayBest>-1 && i2InnLayBest>-1) {
242 xvtx = 0.5*(xclInnLay[i1InnLayBest]+xclInnLay[i2InnLayBest]);
243 yvtx = 0.5*(yclInnLay[i1InnLayBest]+yclInnLay[i2InnLayBest]);
244 zvtx = 0.5*(zclInnLay[i1InnLayBest]+zclInnLay[i2InnLayBest]);
245 rvtx = TMath::Sqrt(xvtx*xvtx+yvtx*yvtx);
246 if(rvtx<fMaxVtxRadius[ilayer]) {
247 ncontributors = ilayer;
248 pos[0] = xvtx;
249 pos[1] = yvtx;
250 pos[2] = zvtx;
251 err[0]=TMath::Sqrt(0.25*(e2xclInnLay[i1InnLayBest]+e2xclInnLay[i2InnLayBest]));
252 err[1]=TMath::Sqrt(0.25*(e2yclInnLay[i1InnLayBest]+e2yclInnLay[i2InnLayBest]));
253 err[2]=TMath::Sqrt(0.25*(e2zclInnLay[i1InnLayBest]+e2zclInnLay[i2InnLayBest]));
254 }
81ba01de 255
7e33c4e6 256 } else { // give it a try exchanging InnLay and OutLay
257
81ba01de 258 // OutLay - first cluster
259 for(i1InnLay=0; i1InnLay<nclOutLayStored; i1InnLay++) {
260 p1[0]=xclOutLay[i1InnLay];
261 p1[1]=yclOutLay[i1InnLay];
262 p1[2]=zclOutLay[i1InnLay];
263 // OutLay - second cluster
264 for(i2InnLay=i1InnLay+1; i2InnLay<nclOutLayStored; i2InnLay++) {
265 if(modclOutLay[i1InnLay]==modclOutLay[i2InnLay]) continue;
266 p2[0]=xclOutLay[i2InnLay];
267 p2[1]=yclOutLay[i2InnLay];
268 p2[2]=zclOutLay[i2InnLay];
269 // look for point on InnLay
270 AliStrLine outLayline(p1,p2,kTRUE);
271 for(iOutLay=0; iOutLay<nclInnLayStored; iOutLay++) {
272 p3[0]=xclInnLay[iOutLay];
273 p3[1]=yclInnLay[iOutLay];
274 p3[2]=zclInnLay[iOutLay];
275 //printf(" %f\n",InnLayline.GetDistFromPoint(p3));
276 matchOutLayValue=outLayline.GetDistFromPoint(p3);
277 distxyInnLay = (p1[0]-p2[0])*(p1[0]-p2[0])+(p1[1]-p2[1])*(p1[1]-p2[1]);
278 if(matchOutLayValue<fMaxDistOnOuterLayer &&
279 distxyInnLay>distxyInnLayBest) {
280 distxyInnLayBest=distxyInnLay;
281 i1InnLayBest=i1InnLay;
282 i2InnLayBest=i2InnLay;
283 }
284 }
285 } // OutLay - second cluster
286 } // OutLay - first cluster
81ba01de 287
7e33c4e6 288 if(i1InnLayBest>-1 && i2InnLayBest>-1) {
289 xvtx = 0.5*(xclOutLay[i1InnLayBest]+xclOutLay[i2InnLayBest]);
290 yvtx = 0.5*(yclOutLay[i1InnLayBest]+yclOutLay[i2InnLayBest]);
291 zvtx = 0.5*(zclOutLay[i1InnLayBest]+zclOutLay[i2InnLayBest]);
292 rvtx = TMath::Sqrt(xvtx*xvtx+yvtx*yvtx);
293 if(rvtx<fMaxVtxRadius[ilayer]) {
294 ncontributors = ilayer2;
295 pos[0] = xvtx;
296 pos[1] = yvtx;
297 pos[2] = zvtx;
298 err[0]=TMath::Sqrt(0.25*(e2xclOutLay[i1InnLayBest]+e2xclOutLay[i2InnLayBest]));
299 err[1]=TMath::Sqrt(0.25*(e2yclOutLay[i1InnLayBest]+e2yclOutLay[i2InnLayBest]));
300 err[2]=TMath::Sqrt(0.25*(e2zclOutLay[i1InnLayBest]+e2zclOutLay[i2InnLayBest]));
301 }
81ba01de 302 }
7e33c4e6 303 } // give it a try exchanging InnLay and OutLay
b107ee21 304
3acc14d5 305 fCurrentVertex = new AliESDVertex(pos,err,"cosmics");
3acc14d5 306 fCurrentVertex->SetTitle("cosmics fake vertex");
b107ee21 307 fCurrentVertex->SetNContributors(ncontributors);
308 //fCurrentVertex->Print();
3acc14d5 309
310 delete recpoints;
3acc14d5 311
312 return fCurrentVertex;
313}
308c2f7c 314
3acc14d5 315//-------------------------------------------------------------------------
316void AliITSVertexerCosmics::PrintStatus() const
317{
318 // Print current status
319 printf("=======================================================\n");
b8ed1a92 320 printf(" fMaxDistOnOuterLayer: %f\n",fMaxDistOnOuterLayer);
321 printf(" fMaxVtxRadius[0]: %f\n",fMaxVtxRadius[0]);
3acc14d5 322 printf(" fMinDist2Vtxs: %f\n",fMinDist2Vtxs);
3acc14d5 323 printf("=======================================================\n");
324}
325//-------------------------------------------------------------------------