Another histos for lumi
[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 **************************************************************************/
d531b7a1 15#include "AliITSVertexerZ.h"
0c6af5c9 16#include<TBranch.h>
7299b7a8 17#include<TClonesArray.h>
0c6af5c9 18#include<TH1.h>
d531b7a1 19#include <TString.h>
0c6af5c9 20#include<TTree.h>
308c2f7c 21#include "AliESDVertex.h"
32e63e47 22#include "AliITSgeomTGeo.h"
d531b7a1 23#include "AliITSRecPoint.h"
b21c1af0 24#include "AliITSRecPointContainer.h"
7299b7a8 25#include "AliITSZPoint.h"
0c6af5c9 26
27/////////////////////////////////////////////////////////////////
28// this class implements a fast method to determine
29// the Z coordinate of the primary vertex
30// for p-p collisions it seems to give comparable or better results
31// with respect to what obtained with AliITSVertexerPPZ
32// It can be used successfully with Pb-Pb collisions
33////////////////////////////////////////////////////////////////
34
fe7d86eb 35using std::endl;
36using std::cout;
0c6af5c9 37ClassImp(AliITSVertexerZ)
38
39
40
41//______________________________________________________________________
8221b41b 42AliITSVertexerZ::AliITSVertexerZ():AliITSVertexer(),
43fFirstL1(0),
44fLastL1(0),
45fFirstL2(0),
46fLastL2(0),
47fDiffPhiMax(0),
8221b41b 48fZFound(0),
49fZsig(0.),
50fZCombc(0),
8221b41b 51fLowLim(0.),
52fHighLim(0.),
53fStepCoarse(0),
8221b41b 54fTolerance(0.),
7299b7a8 55fMaxIter(0),
1e6316d8 56fWindowWidth(0),
57fSearchForPileup(kTRUE)
58{
0c6af5c9 59 // Default constructor
7299b7a8 60 SetDiffPhiMax();
61 SetFirstLayerModules();
62 SetSecondLayerModules();
63 SetLowLimit();
64 SetHighLimit();
65 SetBinWidthCoarse();
66 SetTolerance();
67 SetPPsetting();
6fd990e3 68 ConfigIterations();
7299b7a8 69 SetWindowWidth();
0c6af5c9 70}
71
72//______________________________________________________________________
308c2f7c 73AliITSVertexerZ::AliITSVertexerZ(Float_t x0, Float_t y0):AliITSVertexer(),
8221b41b 74fFirstL1(0),
75fLastL1(0),
76fFirstL2(0),
77fLastL2(0),
78fDiffPhiMax(0),
8221b41b 79fZFound(0),
80fZsig(0.),
81fZCombc(0),
8221b41b 82fLowLim(0.),
83fHighLim(0.),
84fStepCoarse(0),
8221b41b 85fTolerance(0.),
7299b7a8 86fMaxIter(0),
1e6316d8 87fWindowWidth(0),
88fSearchForPileup(kTRUE)
89{
0c6af5c9 90 // Standard Constructor
91 SetDiffPhiMax();
0c6af5c9 92 SetFirstLayerModules();
93 SetSecondLayerModules();
0c6af5c9 94 SetLowLimit();
95 SetHighLimit();
96 SetBinWidthCoarse();
0c6af5c9 97 SetTolerance();
ecc64c3f 98 SetPPsetting();
6fd990e3 99 ConfigIterations();
7299b7a8 100 SetWindowWidth();
60b9526b 101 SetVtxStart((Double_t)x0,(Double_t)y0,0.);
0c6af5c9 102
103}
104
105//______________________________________________________________________
0c6af5c9 106AliITSVertexerZ::~AliITSVertexerZ() {
ecc64c3f 107 // Destructor
108 delete fZCombc;
0c6af5c9 109}
110
111//______________________________________________________________________
6fd990e3 112void AliITSVertexerZ::ConfigIterations(Int_t noiter,Float_t *ptr){
113 // configure the iterative procedure to gain efficiency for
114 // pp events with very low multiplicity
bf2e0ad4 115 Float_t defaults[5]={0.02,0.05,0.1,0.2,0.3};
6fd990e3 116 fMaxIter=noiter;
117 if(noiter>5){
118 Error("ConfigIterations","Maximum number of iterations is 5\n");
119 fMaxIter=5;
120 }
121 for(Int_t j=0;j<5;j++)fPhiDiffIter[j]=defaults[j];
122 if(ptr)for(Int_t j=0;j<fMaxIter;j++)fPhiDiffIter[j]=ptr[j];
123}
124
125//______________________________________________________________________
8c32ba44 126Int_t AliITSVertexerZ::GetPeakRegion(TH1F*h, Int_t &binmin, Int_t &binmax){
debb3dde 127 // Finds a region around a peak in the Z histogram
128 // Case of 2 peaks is treated
129 Int_t imax=h->GetNbinsX();
130 Float_t maxval=0;
131 Int_t bi1=h->GetMaximumBin();
132 Int_t bi2=0;
133 for(Int_t i=imax;i>=1;i--){
134 if(h->GetBinContent(i)>maxval){
135 maxval=h->GetBinContent(i);
136 bi2=i;
137 }
138 }
139 Int_t npeaks=0;
140
141 if(bi1==bi2){
142 binmin=bi1-3;
143 binmax=bi1+3;
144 npeaks=1;
145 }else{
146 TH1F *copy = new TH1F(*h);
147 copy->SetBinContent(bi1,0.);
148 copy->SetBinContent(bi2,0.);
149 Int_t l1=TMath::Max(bi1-3,1);
150 Int_t l2=TMath::Min(bi1+3,h->GetNbinsX());
151 Float_t cont1=copy->Integral(l1,l2);
152 Int_t ll1=TMath::Max(bi2-3,1);
153 Int_t ll2=TMath::Min(bi2+3,h->GetNbinsX());
154 Float_t cont2=copy->Integral(ll1,ll2);
155 if(cont1>cont2){
156 binmin=l1;
157 binmax=l2;
158 npeaks=1;
159 }
160 if(cont2>cont1){
161 binmin=ll1;
162 binmax=ll2;
163 npeaks=1;
164 }
165 if(cont1==cont2){
166 binmin=l1;
167 binmax=ll2;
168 if(bi2-bi1==1) npeaks=1;
169 else npeaks=2;
170 }
171 delete copy;
172 }
173 return npeaks;
174}
175//______________________________________________________________________
308c2f7c 176AliESDVertex* AliITSVertexerZ::FindVertexForCurrentEvent(TTree *itsClusterTree){
d681bb2d 177 // Defines the AliESDVertex for the current event
308c2f7c 178 VertexZFinder(itsClusterTree);
6fd990e3 179 Int_t ntrackl=0;
180 for(Int_t iteraz=0;iteraz<fMaxIter;iteraz++){
181 if(fCurrentVertex) ntrackl=fCurrentVertex->GetNContributors();
182 if(!fCurrentVertex || ntrackl==0 || ntrackl==-1){
183 Float_t diffPhiMaxOrig=fDiffPhiMax;
184 fDiffPhiMax=GetPhiMaxIter(iteraz);
308c2f7c 185 VertexZFinder(itsClusterTree);
6fd990e3 186 fDiffPhiMax=diffPhiMaxOrig;
187 }
188 }
1ff24d0a 189 if(fComputeMultiplicity) FindMultiplicity(itsClusterTree);
6fd990e3 190 return fCurrentVertex;
191}
192
193//______________________________________________________________________
308c2f7c 194void AliITSVertexerZ::VertexZFinder(TTree *itsClusterTree){
6fd990e3 195 // Defines the AliESDVertex for the current event
049c07b3 196 delete fCurrentVertex;
0c6af5c9 197 fCurrentVertex = 0;
5279841d 198 Double_t startPos[3]={GetNominalPos()[0],GetNominalPos()[1],GetNominalPos()[2]};
199 Double_t startCov[6]={GetNominalCov()[0],GetNominalCov()[1],GetNominalCov()[2],
200 GetNominalCov()[3],GetNominalCov()[4],GetNominalCov()[5]};
6b4d9537 201 ResetVertex();
0c6af5c9 202 TClonesArray *itsRec = 0;
27167524 203 // lc1 and gc1 are local and global coordinates for layer 1
54f95b99 204 Float_t gc1[3]={0.,0.,0.}; // ; for(Int_t ii=0; ii<3; ii++) gc1[ii]=0.;
ecc64c3f 205 // lc2 and gc2 are local and global coordinates for layer 2
54f95b99 206 Float_t gc2[3]={0.,0.,0.}; //; for(Int_t ii=0; ii<3; ii++) gc2[ii]=0.;
b21c1af0 207 AliITSRecPointContainer* rpcont=AliITSRecPointContainer::Instance();
3457dd2d 208 rpcont->FetchClusters(0,itsClusterTree);
b21c1af0 209 if(!rpcont->IsSPDActive()){
fea0ad94 210 AliWarning("Null pointer for RecPoints branch, vertex not calculated");
211 ResetHistograms();
5279841d 212 fCurrentVertex = new AliESDVertex(startPos,startCov,99999.,-2);
fea0ad94 213 return;
214 }
0c6af5c9 215
0c6af5c9 216 Int_t nrpL1 = 0;
217 Int_t nrpL2 = 0;
1cc75a0b 218 nrpL1=rpcont->GetNClustersInLayerFast(1);
219 nrpL2=rpcont->GetNClustersInLayerFast(2);
27167524 220
0c6af5c9 221 if(nrpL1 == 0 || nrpL2 == 0){
fea0ad94 222 AliDebug(1,Form("No RecPoints in at least one SPD layer (%d %d)",nrpL1,nrpL2));
0c6af5c9 223 ResetHistograms();
5279841d 224 fCurrentVertex = new AliESDVertex(startPos,startCov,99999.,-2);
6fd990e3 225 return;
0c6af5c9 226 }
ecc64c3f 227 // Force a coarse bin size of 200 microns if the number of clusters on layer 2
228 // is low
229 if(nrpL2<fPPsetting[0])SetBinWidthCoarse(fPPsetting[1]);
ecc64c3f 230 // By default nbincoarse=(10+10)/0.01=2000
231 Int_t nbincoarse = static_cast<Int_t>((fHighLim-fLowLim)/fStepCoarse);
ecc64c3f 232 if(fZCombc)delete fZCombc;
233 fZCombc = new TH1F("fZCombc","Z",nbincoarse,fLowLim,fLowLim+nbincoarse*fStepCoarse);
7299b7a8 234
27167524 235 /* Test the ffect of mutiple scatternig on error. Negligible
7299b7a8 236 // Multiple scattering
237 Float_t beta=1.,pmed=0.875; //pmed=875 MeV (for tracks with dphi<0.01 rad)
238 Float_t beta2=beta*beta;
239 Float_t p2=pmed*pmed;
240 Float_t rBP=3; //Beam Pipe radius = 3cm
241 Float_t dBP=0.08/35.3; // 800 um of Be
242 Float_t dL1=0.01; //approx. 1% of radiation length
243 Float_t theta2BP=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(dBP);
244 Float_t theta2L1=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(dL1);
245*/
54f95b99 246 Int_t nEntriesMod[kNSPDMod];
247 TClonesArray* recpArr[kNSPDMod];
248 for(Int_t modul=0; modul<kNSPDMod; ++modul) {
249 if(!fUseModule[modul]) {
250 nEntriesMod[modul]=0;
251 recpArr[modul]=0;
252 } else {
253 recpArr[modul]=rpcont->UncheckedGetClusters(modul);
254 nEntriesMod[modul]=recpArr[modul]->GetEntriesFast();
255 }
256 }
257
27167524 258 Int_t maxdim=TMath::Min(nrpL1*nrpL2,50000); // temporary; to limit the size in PbPb
f5f6da22 259 static TClonesArray points("AliITSZPoint",maxdim);
7299b7a8 260 Int_t nopoints =0;
27167524 261 for(Int_t modul1= fFirstL1; modul1<=fLastL1;modul1++){ // Loop on modules of layer 1
8c42830a 262 if(!fUseModule[modul1]) continue;
27167524 263 UShort_t ladder=int(modul1/4)+1; // ladders are numbered starting from 1
54f95b99 264 TClonesArray *prpl1=recpArr[modul1]; //rpcont->UncheckedGetClusters(modul1);
265 Int_t nrecp1 = nEntriesMod[modul1]; //prpl1->GetEntries();
27167524 266 for(Int_t j1=0;j1<nrecp1;j1++){
54f95b99 267 AliITSRecPoint *recp1 = (AliITSRecPoint*)prpl1->At(j1);
268 recp1->GetGlobalXYZ(gc1);
308c2f7c 269 gc1[0]-=GetNominalPos()[0]; // Possible beam offset in the bending plane
270 gc1[1]-=GetNominalPos()[1]; // " "
27167524 271 Float_t phi1 = TMath::ATan2(gc1[1],gc1[0]);
54f95b99 272 if(phi1<0)phi1+=TMath::TwoPi();
27167524 273 for(Int_t ladl2=0 ; ladl2<fLadOnLay2*2+1;ladl2++){
274 for(Int_t k=0;k<4;k++){
275 Int_t ladmod=fLadders[ladder-1]+ladl2;
32e63e47 276 if(ladmod>AliITSgeomTGeo::GetNLadders(2)) ladmod=ladmod-AliITSgeomTGeo::GetNLadders(2);
277 Int_t modul2=AliITSgeomTGeo::GetModuleIndex(2,ladmod,k+1);
e917bef4 278 if(modul2<0)continue;
8c42830a 279 if(!fUseModule[modul2]) continue;
54f95b99 280 itsRec=recpArr[modul2]; // rpcont->UncheckedGetClusters(modul2);
281 Int_t nrecp2 = nEntriesMod[modul2]; // itsRec->GetEntries();
27167524 282 for(Int_t j2=0;j2<nrecp2;j2++){
54f95b99 283 AliITSRecPoint *recp2 = (AliITSRecPoint*)itsRec->At(j2);
284 recp2->GetGlobalXYZ(gc2);
308c2f7c 285 gc2[0]-=GetNominalPos()[0];
286 gc2[1]-=GetNominalPos()[1];
27167524 287 Float_t phi2 = TMath::ATan2(gc2[1],gc2[0]);
54f95b99 288 if(phi2<0)phi2+=TMath::TwoPi();
27167524 289
290 Float_t diff = TMath::Abs(phi2-phi1);
54f95b99 291 if(diff>TMath::Pi())diff=TMath::TwoPi()-diff;
27167524 292 if(diff<fDiffPhiMax){
54f95b99 293 Float_t r1=TMath::Sqrt(gc1[0]*gc1[0]+gc1[1]*gc1[1]);
294 Float_t zc1=gc1[2];
295 Float_t erz1=recp1->GetSigmaZ2();
296 Float_t r2=TMath::Sqrt(gc2[0]*gc2[0]+gc2[1]*gc2[1]);
297 Float_t zc2=gc2[2];
298 Float_t erz2=recp2->GetSigmaZ2();
27167524 299 // Float_t tgth=(zc2[j]-zc1[i])/(r2-r1); // slope (used for multiple scattering)
300 Float_t zr0=(r2*zc1-r1*zc2)/(r2-r1); //Z @ null radius
54f95b99 301 Float_t ezr0q=(r2*r2*erz1+r1*r1*erz2)/((r2-r1)*(r2-r1)); //error on Z @ null radius
302 /*
303 // Multiple scattering
304 ezr0q+=r1*r1*(1+tgth*tgth)*theta2L1/2; // multiple scattering in layer 1
305 ezr0q+=rBP*rBP*(1+tgth*tgth)*theta2BP/2; // multiple scattering in beam pipe
306 */
f5f6da22 307 if(nopoints<maxdim) new(points[nopoints++])AliITSZPoint(zr0,ezr0q);
27167524 308 fZCombc->Fill(zr0);
309 }
310 }
27167524 311 }
0c6af5c9 312 }
313 }
314 }
7299b7a8 315
f5f6da22 316 points.Sort();
7299b7a8 317
6fd990e3 318 Double_t contents = fZCombc->GetEntries()- fZCombc->GetBinContent(0)-fZCombc->GetBinContent(nbincoarse+1);
319 if(contents<1.){
320 // Warning("FindVertexForCurrentEvent","Insufficient number of rec. points\n");
0c6af5c9 321 ResetHistograms();
5279841d 322 fCurrentVertex = new AliESDVertex(startPos,startCov,99999.,-1);
f5f6da22 323 points.Clear();
6fd990e3 324 return;
0c6af5c9 325 }
ecc64c3f 326
327 TH1F *hc = fZCombc;
ecc64c3f 328
ecc64c3f 329
8c42830a 330 if(hc->GetBinContent(hc->GetMaximumBin())<3)hc->Rebin(4);
debb3dde 331 Int_t binmin,binmax;
332 Int_t nPeaks=GetPeakRegion(hc,binmin,binmax);
4be14da5 333 if(nPeaks==2)AliDebug(2,"2 peaks found");
7299b7a8 334 Float_t zm =0.;
335 Float_t ezm =0.;
336 Float_t lim1 = hc->GetBinLowEdge(binmin);
337 Float_t lim2 = hc->GetBinLowEdge(binmax)+hc->GetBinWidth(binmax);
4be14da5 338 Float_t widthSR=lim2-lim1;
7299b7a8 339
340 if(nPeaks ==1 && (lim2-lim1)<fWindowWidth){
341 Float_t c=(lim1+lim2)/2.;
342 lim1=c-fWindowWidth/2.;
343 lim2=c+fWindowWidth/2.;
ecc64c3f 344 }
7299b7a8 345 Int_t niter = 0, ncontr=0;
346 do {
347 // symmetrization
348 if(zm !=0.){
349 Float_t semilarg=TMath::Min((lim2-zm),(zm-lim1));
350 lim1=zm - semilarg;
351 lim2=zm + semilarg;
0c6af5c9 352 }
7299b7a8 353
354 zm=0.;
355 ezm=0.;
356 ncontr=0;
896141ab 357 for(Int_t i =0; i<points.GetEntriesFast(); i++){
f5f6da22 358 AliITSZPoint* p=(AliITSZPoint*)points.UncheckedAt(i);
7299b7a8 359 if(p->GetZ()>lim1 && p->GetZ()<lim2){
360 Float_t deno = p->GetErrZ();
361 zm+=p->GetZ()/deno;
362 ezm+=1./deno;
363 ncontr++;
ecc64c3f 364 }
365 }
2b8b4286 366 if(ezm>0) {
367 zm/=ezm;
368 ezm=TMath::Sqrt(1./ezm);
369 }
7299b7a8 370 niter++;
371 } while(niter<10 && TMath::Abs((zm-lim1)-(lim2-zm))>fTolerance);
4be14da5 372 if(nPeaks==2) ezm=widthSR;
5279841d 373 Double_t position[3]={GetNominalPos()[0],GetNominalPos()[1],zm};
374 Double_t covmatrix[6]={GetNominalCov()[0],0.,GetNominalCov()[2],0.,0.,ezm};
375 fCurrentVertex = new AliESDVertex(position,covmatrix,99999.,ncontr);
12e3ead8 376 fCurrentVertex->SetTitle("vertexer: Z");
bf2e0ad4 377 fCurrentVertex->SetDispersion(fDiffPhiMax);
6b4d9537 378 fNoVertices=1;
f5f6da22 379 points.Clear();
1e6316d8 380 if(fSearchForPileup && ncontr>fMinTrackletsForPilup){
8c32ba44 381 Float_t secPeakPos;
382 Int_t ncontr2=FindSecondPeak(fZCombc,binmin,binmax,secPeakPos);
383 if(ncontr2>=fMinTrackletsForPilup){
384 fIsPileup=kTRUE;
6b4d9537 385 fNoVertices=2;
8c32ba44 386 fZpuv=secPeakPos;
387 fNTrpuv=ncontr2;
6b4d9537 388 AliESDVertex secondVert(secPeakPos,0.1,ncontr2);
389 fVertArray = new AliESDVertex[2];
390 fVertArray[0]=(*fCurrentVertex);
391 fVertArray[1]=secondVert;
8c32ba44 392 }
2c3a7cd0 393 }
6b4d9537 394 if(fNoVertices==1){
395 fVertArray = new AliESDVertex[1];
396 fVertArray[0]=(*fCurrentVertex);
397 }
398
0c6af5c9 399 ResetHistograms();
6fd990e3 400 return;
0c6af5c9 401}
402
8c32ba44 403//_____________________________________________________________________
f510fd70 404Int_t AliITSVertexerZ::FindSecondPeak(TH1F* h, Int_t binmin,Int_t binmax, Float_t& secPeakPos){
405 // Resets bin contents between binmin and binmax and then search
406 // for a second peak position
8c32ba44 407 for(Int_t i=binmin-1;i<=binmax+1;i++){
408 h->SetBinContent(i,0.);
409 }
410 Int_t secPeakBin=h->GetMaximumBin();
411 secPeakPos=h->GetBinCenter(secPeakBin);
70a3283c 412 Int_t secPeakCont=(Int_t)h->GetBinContent(secPeakBin);
413 secPeakCont+=(Int_t)h->GetBinContent(secPeakBin-1);
414 secPeakCont+=(Int_t)h->GetBinContent(secPeakBin+1);
415 secPeakCont+=(Int_t)h->GetBinContent(secPeakBin-2);
416 secPeakCont+=(Int_t)h->GetBinContent(secPeakBin+2);
8c32ba44 417 return secPeakCont;
418}
419
0c6af5c9 420//_____________________________________________________________________
421void AliITSVertexerZ::ResetHistograms(){
422 // delete TH1 data members
423 if(fZCombc)delete fZCombc;
0c6af5c9 424 fZCombc = 0;
0c6af5c9 425}
426
0c6af5c9 427//________________________________________________________
428void AliITSVertexerZ::PrintStatus() const {
429 // Print current status
430 cout <<"=======================================================\n";
431 cout <<" First layer first and last modules: "<<fFirstL1<<", ";
432 cout <<fLastL1<<endl;
433 cout <<" Second layer first and last modules: "<<fFirstL2<<", ";
434 cout <<fLastL2<<endl;
435 cout <<" Max Phi difference: "<<fDiffPhiMax<<endl;
436 cout <<"Limits for Z histograms: "<<fLowLim<<"; "<<fHighLim<<endl;
7299b7a8 437 cout <<"Bin sizes for coarse z histos "<<fStepCoarse<<endl;
0c6af5c9 438 cout <<" Current Z "<<fZFound<<"; Z sig "<<fZsig<<endl;
ecc64c3f 439 if(fZCombc){
440 cout<<"fZCombc exists - entries="<<fZCombc->GetEntries()<<endl;
441 }
442 else{
443 cout<<"fZCombc does not exist\n";
444 }
0c6af5c9 445
446 cout <<"=======================================================\n";
447}
448