primary Z coord. vertex finder. Possibly a better and faster solution for pp. Efficie...
[u/mrichter/AliRoot.git] / ITS / AliITSVertexerZ.cxx
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0c6af5c9 1/**************************************************************************
2 * Copyright(c) 1998-2003, 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#include <AliITSVertexerZ.h>
16#include <Riostream.h>
17#include <TString.h>
18#include <AliITS.h>
19#include "AliITSLoader.h"
20#include <AliRun.h>
21#include<TBranch.h>
22#include<TClonesArray.h>
23#include<TH1.h>
24#include<TMath.h>
25#include<TTree.h>
26#include <AliITSgeom.h>
27#include <AliITSRecPoint.h>
28
29/////////////////////////////////////////////////////////////////
30// this class implements a fast method to determine
31// the Z coordinate of the primary vertex
32// for p-p collisions it seems to give comparable or better results
33// with respect to what obtained with AliITSVertexerPPZ
34// It can be used successfully with Pb-Pb collisions
35////////////////////////////////////////////////////////////////
36
37ClassImp(AliITSVertexerZ)
38
39
40
41//______________________________________________________________________
42AliITSVertexerZ::AliITSVertexerZ():AliITSVertexer() {
43 // Default constructor
44 SetDiffPhiMax(0);
45 fX0 = 0.;
46 fY0 = 0.;
47 SetFirstLayerModules(0);
48 SetSecondLayerModules(0);
49 fZFound = 0;
50 fZsig = 0.;
51 fITS = 0;
52 fZCombc = 0;
53 fZCombf = 0;
54 SetLowLimit(0.);
55 SetHighLimit(0.);
56 SetBinWidthCoarse(0.);
57 SetBinWidthFine(0.);
58 SetTolerance(0.);
59}
60
61//______________________________________________________________________
62AliITSVertexerZ::AliITSVertexerZ(TString fn, Float_t x0, Float_t y0):AliITSVertexer(fn) {
63 // Standard Constructor
64 SetDiffPhiMax();
65 fX0 = x0;
66 fY0 = y0;
67 SetFirstLayerModules();
68 SetSecondLayerModules();
69 fZFound = 0;
70 fZsig = 0.;
71 fITS = 0;
72 fZCombc = 0;
73 fZCombf = 0;
74 SetLowLimit();
75 SetHighLimit();
76 SetBinWidthCoarse();
77 SetBinWidthFine();
78 SetTolerance();
79
80}
81
82//______________________________________________________________________
83AliITSVertexerZ::AliITSVertexerZ(const AliITSVertexerZ &vtxr) : AliITSVertexer(vtxr) {
84 // Copy constructor
85 // Copies are not allowed. The method is protected to avoid misuse.
86 Error("AliITSVertexerZ","Copy constructor not allowed\n");
87}
88
89//______________________________________________________________________
90AliITSVertexerZ& AliITSVertexerZ::operator=(const AliITSVertexerZ& /* vtxr */){
91 // Assignment operator
92 // Assignment is not allowed. The method is protected to avoid misuse.
93 Error("= operator","Assignment operator not allowed\n");
94 return *this;
95}
96
97
98//______________________________________________________________________
99AliITSVertexerZ::~AliITSVertexerZ() {
100 // Default Destructor
101 fITS = 0;
102 if(fZCombc)delete fZCombc;
103 if(fZCombf)delete fZCombf;
104}
105
106//______________________________________________________________________
107AliITSVertex* AliITSVertexerZ::FindVertexForCurrentEvent(Int_t evnumber){
108 // Defines the AliITSVertex for the current event
109
110 fCurrentVertex = 0;
111 AliRunLoader *rl =AliRunLoader::GetRunLoader();
112 AliITSLoader* itsLoader = (AliITSLoader*) rl->GetLoader("ITSLoader");
113 itsLoader->ReloadRecPoints();
114
115 rl->GetEvent(evnumber);
116
117 if(!fITS) {
118 fITS = (AliITS*)gAlice->GetModule("ITS");
119 if(!fITS) {
120 Error("FindVertexForCurrentEvent","AliITS object was not found");
121 return fCurrentVertex;
122 }
123 }
124
125 fITS->SetTreeAddress();
126
127 AliITSgeom *geom = fITS->GetITSgeom();
128
129 TTree *tR = itsLoader->TreeR();
130 TClonesArray *itsRec = 0;
131 Float_t lc[3]; for(Int_t ii=0; ii<3; ii++) lc[ii]=0.;
132 Float_t gc[3]; for(Int_t ii=0; ii<3; ii++) gc[ii]=0.;
133 Float_t lc2[3]; for(Int_t ii=0; ii<3; ii++) lc2[ii]=0.;
134 Float_t gc2[3]; for(Int_t ii=0; ii<3; ii++) gc2[ii]=0.;
135
136 itsRec = fITS->RecPoints();
137 TBranch *branch = tR->GetBranch("ITSRecPoints");
138
139 Int_t nbinfine = static_cast<Int_t>((fHighLim-fLowLim)/fStepFine);
140 Int_t nbincoarse = static_cast<Int_t>((fHighLim-fLowLim)/fStepCoarse);
141 if(fZCombc)delete fZCombc;
142 fZCombc = new TH1F("fZCombc","Z",nbincoarse,fLowLim,fLowLim+nbincoarse*fStepCoarse);
143 if(fZCombf)delete fZCombf;
144 fZCombf = new TH1F("fZCombf","Z",nbinfine,fLowLim,fLowLim+nbinfine*fStepFine);
145
146 Int_t nrpL1 = 0;
147 Int_t nrpL2 = 0;
148 for(Int_t module= fFirstL1; module<=fLastL1;module++){
149 if(module%4==0 || module%4==3)continue;
150 branch->GetEvent(module);
151 nrpL1+= itsRec->GetEntries();
152 fITS->ResetRecPoints();
153 }
154 for(Int_t module= fFirstL2; module<=fLastL2;module++){
155 branch->GetEvent(module);
156 nrpL2+= itsRec->GetEntries();
157 fITS->ResetRecPoints();
158 }
159 cout<<"nrpL1 = "<<nrpL1<<"; nrpL2= "<<nrpL2<<endl;
160 if(nrpL1 == 0 || nrpL2 == 0){
161 cout<<"achi, achi\n";
162 ResetHistograms();
163 return fCurrentVertex;
164 }
165 Float_t *xc1 = new Float_t [nrpL1];
166 Float_t *yc1 = new Float_t [nrpL1];
167 Float_t *zc1 = new Float_t [nrpL1];
168 Float_t *phi1 = new Float_t [nrpL1];
169 Float_t *xc2 = new Float_t [nrpL2];
170 Float_t *yc2 = new Float_t [nrpL2];
171 Float_t *zc2 = new Float_t [nrpL2];
172 Float_t *phi2 = new Float_t [nrpL2];
173 Int_t ind = 0;
174 for(Int_t module= fFirstL1; module<=fLastL1;module++){
175 if(module%4==0 || module%4==3)continue;
176 branch->GetEvent(module);
177 Int_t nrecp1 = itsRec->GetEntries();
178 for(Int_t j=0;j<nrecp1;j++){
179 AliITSRecPoint *recp = (AliITSRecPoint*)itsRec->At(j);
180 lc[0]=recp->GetX();
181 lc[2]=recp->GetZ();
182 geom->LtoG(module,lc,gc);
183 gc[0]-=fX0;
184 gc[1]-=fY0;
185 xc1[ind]=gc[0];
186 yc1[ind]=gc[1];
187 zc1[ind]=gc[2];
188 phi1[ind] = TMath::ATan2(gc[1],gc[0]);
189 if(phi1[ind]<0)phi1[ind]=2*TMath::Pi()+phi1[ind];
190 ind++;
191 }
192 fITS->ResetRecPoints();
193 }
194 ind = 0;
195 for(Int_t module= fFirstL2; module<=fLastL2;module++){
196 branch->GetEvent(module);
197 Int_t nrecp2 = itsRec->GetEntries();
198 for(Int_t j=0;j<nrecp2;j++){
199 AliITSRecPoint *recp = (AliITSRecPoint*)itsRec->At(j);
200 lc[0]=recp->GetX();
201 lc[2]=recp->GetZ();
202 geom->LtoG(module,lc,gc);
203 gc[0]-=fX0;
204 gc[1]-=fY0;
205 xc2[ind]=gc[0];
206 yc2[ind]=gc[1];
207 zc2[ind]=gc[2];
208 phi2[ind] = TMath::ATan2(gc[1],gc[0]);
209 if(phi2[ind]<0)phi2[ind]=2*TMath::Pi()+phi2[ind];
210 ind++;
211 }
212 fITS->ResetRecPoints();
213 }
214 for(Int_t i=0;i<nrpL1;i++){
215 Float_t r1=TMath::Sqrt(xc1[i]*xc1[i]+yc1[i]*yc1[i]);
216 for(Int_t j=0;j<nrpL2;j++){
217 Float_t diff = TMath::Abs(phi2[j]-phi1[i]);
218 if(diff>TMath::Pi())diff=2.*TMath::Pi()-diff;
219 if(diff<fDiffPhiMax){
220 Float_t r2=TMath::Sqrt(xc2[j]*xc2[j]+yc2[j]*yc2[j]);
221 Float_t zr0=(r2*zc1[i]-r1*zc2[j])/(r2-r1);
222 fZCombf->Fill(zr0);
223 fZCombc->Fill(zr0);
224 }
225 }
226 }
227 delete [] xc1;
228 delete [] yc1;
229 delete [] zc1;
230 delete [] phi1;
231 delete [] xc2;
232 delete [] yc2;
233 delete [] zc2;
234 delete [] phi2;
235 if(fZCombc->GetEntries()==0){
236 Warning("FindVertexForCurrentEvent","Insufficient number of rec. points\n");
237 ResetHistograms();
238 return fCurrentVertex;
239 }
240 else {
241 cout<<"Number of entries in hist. "<<fZCombc->GetEntries()<<endl;
242 }
243 Int_t bi = fZCombc->GetMaximumBin();
244 Float_t centre = fZCombc->GetBinCenter(bi);
245 Int_t n1 = static_cast<Int_t>((centre-fZCombc->GetBinWidth(bi)-fZCombf->GetBinLowEdge(0))/fZCombf->GetBinWidth(0));
246 Int_t n2 = static_cast<Int_t>((centre+fZCombc->GetBinWidth(bi)-fZCombf->GetBinLowEdge(0))/fZCombf->GetBinWidth(0));
247 Int_t niter = 0;
248 Bool_t goon = kTRUE;
249 Int_t num;
250 while(goon){
251 fZFound = 0.;
252 fZsig = 0.;
253 num=0;
254 for(Int_t n=n1;n<=n2;n++){
255 fZFound+=fZCombf->GetBinCenter(n)*fZCombf->GetBinContent(n);
256 num+=static_cast<Int_t>(fZCombf->GetBinContent(n));
257 fZsig+=fZCombf->GetBinCenter(n)*fZCombf->GetBinCenter(n)*fZCombf->GetBinContent(n);
258 }
259 if(num<2){
260 cout<<"ATTENZIONE: num = "<<num<<"; n1= "<<n1<<"; n2 = "<<n2<<endl;
261 fZsig = 0.;
262 }
263 else {
264 fZsig=TMath::Sqrt(fZsig/(num-1)-fZFound*fZFound/num/(num-1));
265 fZFound/=num;
266 }
267 goon = TMath::Abs(TMath::Abs(fZFound-fZCombf->GetBinCenter(n1))-TMath::Abs(fZFound-fZCombf->GetBinCenter(n2)))>fTolerance;
268 cout<<"Simmetria "<<TMath::Abs(TMath::Abs(fZFound-fZCombf->GetBinCenter(n1))-TMath::Abs(fZFound-fZCombf->GetBinCenter(n2)))<<endl;
269 n1 = static_cast<Int_t>((fZFound-fZCombc->GetBinWidth(bi)-fZCombf->GetBinLowEdge(0))/fZCombf->GetBinWidth(0));
270 n2 = static_cast<Int_t>((fZFound+fZCombc->GetBinWidth(bi)-fZCombf->GetBinLowEdge(0))/fZCombf->GetBinWidth(0));
271 niter++;
272 if(niter>=10){
273 goon = kFALSE;
274 Warning("FindVertexForCurrentEvent","The procedure dows not converge\n");
275 }
276 }
277 cout<<"Numer of Iterations "<<niter<<endl<<endl;
278 fCurrentVertex = new AliITSVertex(fZFound,fZsig,num);
279 fCurrentVertex->SetTitle("vertexer: B");
280 ResetHistograms();
281 return fCurrentVertex;
282}
283
284//_____________________________________________________________________
285void AliITSVertexerZ::ResetHistograms(){
286 // delete TH1 data members
287 if(fZCombc)delete fZCombc;
288 if(fZCombf)delete fZCombf;
289 fZCombc = 0;
290 fZCombf = 0;
291}
292
293//______________________________________________________________________
294void AliITSVertexerZ::FindVertices(){
295 // computes the vertices of the events in the range FirstEvent - LastEvent
296 AliRunLoader *rl = AliRunLoader::GetRunLoader();
297 AliITSLoader* itsLoader = (AliITSLoader*) rl->GetLoader("ITSLoader");
298 itsLoader->ReloadRecPoints();
299 for(Int_t i=fFirstEvent;i<=fLastEvent;i++){
300 cout<<"Processing event "<<i<<endl;
301 rl->GetEvent(i);
302 FindVertexForCurrentEvent(i);
303 if(fCurrentVertex){
304 WriteCurrentVertex();
305 }
306 else {
307 if(fDebug>0){
308 cout<<"Vertex not found for event "<<i<<endl;
309 cout<<"fZFound = "<<fZFound<<", fZsig= "<<fZsig<<endl;
310 }
311 }
312 }
313}
314
315//________________________________________________________
316void AliITSVertexerZ::PrintStatus() const {
317 // Print current status
318 cout <<"=======================================================\n";
319 cout <<" First layer first and last modules: "<<fFirstL1<<", ";
320 cout <<fLastL1<<endl;
321 cout <<" Second layer first and last modules: "<<fFirstL2<<", ";
322 cout <<fLastL2<<endl;
323 cout <<" Max Phi difference: "<<fDiffPhiMax<<endl;
324 cout <<"Limits for Z histograms: "<<fLowLim<<"; "<<fHighLim<<endl;
325 cout <<"Bin sizes for coarse and fine z histos "<<fStepCoarse<<"; "<<fStepFine<<endl;
326 cout <<" Current Z "<<fZFound<<"; Z sig "<<fZsig<<endl;
327 cout <<" Debug flag: "<<fDebug<<endl;
328 cout <<"First event to be processed "<<fFirstEvent;
329 cout <<"\n Last event to be processed "<<fLastEvent<<endl;
330
331
332 cout <<"=======================================================\n";
333}
334