Label for the ITS tracklets (Jan Fiete)
[u/mrichter/AliRoot.git] / HMPID / AliHMPIDRecon.cxx
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d3da6dc4 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// //
18// AliHMPIDRecon //
19// //
20// HMPID class to perfom pattern recognition based on Hough transfrom //
21// for single chamber //
22//////////////////////////////////////////////////////////////////////////
23
a591e55f 24#include "AliHMPIDRecon.h" //class header
d3da6dc4 25#include "AliHMPIDCluster.h" //CkovAngle()
a591e55f 26#include <TRotation.h> //TracePhot()
27#include <TH1D.h> //HoughResponse()
28#include <TClonesArray.h> //CkovAngle()
29#include <AliESDtrack.h> //CkovAngle()
d3da6dc4 30
cdf0e3d9 31 Int_t fPhotCnt; // counter of photons candidate
32 Int_t *fPhotFlag; // flags of photon candidates
33 Double_t *fPhotCkov; // Ckov angles of photon candidates, [rad]
34 Double_t *fPhotPhi; // phis of photons candidates, [rad]
35 Double_t *fPhotWei; // weigths of photon candidates
36 Double_t fCkovSigma2; // sigma2 of the reconstructed ring
37
38 Bool_t fIsWEIGHT; // flag to consider weight procedure
39 Float_t fDTheta; // Step for sliding window
40 Float_t fWindowWidth; // Hough width of sliding window
41
42 Double_t fRingArea; // area of a given ring
43 Double_t fRingAcc; // fraction of the ring accepted by geometry
44 TVector3 fTrkDir; // track direction in LORS at RAD
45 TVector2 fTrkPos; // track positon in LORS at RAD
46 TVector2 fMipPos; // mip positon for a given track
47 TVector2 fPc; // track position at PC
48
49 AliHMPIDParam *fParam; // Pointer to AliHMPIDParam
50
51
d3da6dc4 52//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
c61a7285 53AliHMPIDRecon::AliHMPIDRecon():
54 TTask("RichRec","RichPat"),
55 fPhotCnt(-1),
cdf0e3d9 56 fPhotFlag(0x0),
57 fPhotCkov(0x0),
58 fPhotPhi(0x0),
59 fPhotWei(0x0),
c61a7285 60 fCkovSigma2(0),
61 fIsWEIGHT(kFALSE),
62 fDTheta(0.001),
63 fWindowWidth(0.045),
64 fRingArea(0),
65 fRingAcc(0),
66 fTrkDir(0,0,1), // Just for test
67 fTrkPos(30,40), // Just for test
cdf0e3d9 68 fMipPos(0,0),
69 fPc(0,0),
c61a7285 70 fParam(AliHMPIDParam::Instance())
d3da6dc4 71{
ffb1ac19 72//..
73//init of data members
74//..
75
ffb1ac19 76 fParam->SetRefIdx(fParam->MeanIdxRad()); // initialization of ref index to a default one
77}
78//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
79void AliHMPIDRecon::InitVars(Int_t n)
80{
81//..
82//Init some variables
83//..
84 if(n<0) return;
85 fPhotFlag = new Int_t[n];
86 fPhotCkov = new Double_t[n];
87 fPhotPhi = new Double_t[n];
88 fPhotWei = new Double_t[n];
89//
90}
91//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
606697a8 92void AliHMPIDRecon::DeleteVars()const
ffb1ac19 93{
94//..
95//Delete variables
96//..
97 delete fPhotFlag;
98 delete fPhotCkov;
99 delete fPhotPhi;
100 delete fPhotWei;
d3da6dc4 101}
102//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
afe12692 103void AliHMPIDRecon::CkovAngle(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t nmean,Double_t qthre)
d3da6dc4 104{
105// Pattern recognition method based on Hough transform
59280a5a 106// Arguments: pTrk - track for which Ckov angle is to be found
107// pCluLst - list of clusters for this chamber
108// Returns: - track ckov angle, [rad],
a591e55f 109
ffb1ac19 110 Int_t nClusTot = pCluLst->GetEntries();
111 if(nClusTot>fParam->MultCut()) fIsWEIGHT = kTRUE; // offset to take into account bkg in reconstruction
112 else fIsWEIGHT = kFALSE;
d3da6dc4 113
ffb1ac19 114 InitVars(nClusTot);
115
611e810d 116 Float_t xRa,yRa,th,ph;
a591e55f 117 pTrk->GetHMPIDtrk(xRa,yRa,th,ph); //initialize this track: th and ph angles at middle of RAD
a591e55f 118 SetTrack(xRa,yRa,th,ph);
611e810d 119
ffb1ac19 120 fParam->SetRefIdx(nmean);
d3da6dc4 121
59280a5a 122 Float_t dMin=999,mipX=-1,mipY=-1;Int_t chId=-1,mipId=-1,mipQ=-1;
d3da6dc4 123 fPhotCnt=0;
124 for (Int_t iClu=0; iClu<pCluLst->GetEntriesFast();iClu++){//clusters loop
125 AliHMPIDCluster *pClu=(AliHMPIDCluster*)pCluLst->UncheckedAt(iClu); //get pointer to current cluster
59280a5a 126 chId=pClu->Ch();
afe12692 127 if(pClu->Q()>qthre){ //charge compartible with MIP clusters
a591e55f 128 Float_t dX=fPc.X()-pClu->X(),dY=fPc.Y()-pClu->Y(),d =TMath::Sqrt(dX*dX+dY*dY); //distance between current cluster and intersection point
129 if( d < dMin) {mipId=iClu; dMin=d;mipX=pClu->X();mipY=pClu->Y();mipQ=(Int_t)pClu->Q();} //current cluster is closer, overwrite data for min cluster
130 }else{ //charge compatible with photon cluster
131 Double_t thetaCer,phiCer;
132 if(FindPhotCkov(pClu->X(),pClu->Y(),thetaCer,phiCer)){ //find ckov angle for this photon candidate
133 fPhotCkov[fPhotCnt]=thetaCer; //actual theta Cerenkov (in TRS)
b4ad85e9 134 fPhotPhi [fPhotCnt]=phiCer; //actual phi Cerenkov (in TRS): -pi to come back to "unusual" ref system (X,Y,-Z)
28500fe1 135 //PH Printf("photon n. %i reconstructed theta = %f",fPhotCnt,fPhotCkov[fPhotCnt]);
a591e55f 136 fPhotCnt++; //increment counter of photon candidates
137 }
59280a5a 138 }
d3da6dc4 139 }//clusters loop
4598109f 140 fMipPos.Set(mipX,mipY);
76fd1a96 141 if(fPhotCnt<=3) pTrk->SetHMPIDsignal(kNoPhotAccept); //no reconstruction with <=3 photon candidates
2d1a9b21 142 Int_t iNrec=FlagPhot(HoughResponse()); //flag photons according to individual theta ckov with respect to most probable
143 pTrk->SetHMPIDmip(mipX,mipY,mipQ,iNrec); //store mip info
59280a5a 144
a591e55f 145 if(mipId==-1) {pTrk->SetHMPIDsignal(kMipQdcCut); return;} //no clusters with QDC more the threshold at all
ffb1ac19 146 if(dMin>fParam->DistCut()) {pTrk->SetHMPIDsignal(kMipDistCut); return;} //closest cluster with enough charge is still too far from intersection
a591e55f 147 pTrk->SetHMPIDcluIdx(chId,mipId); //set index of cluster
2d1a9b21 148 if(iNrec<1){
149 pTrk->SetHMPIDsignal(kNoPhotAccept); //no photon candidates are accepted
76fd1a96 150 }
151 else {
2d1a9b21 152 Double_t thetaC = FindRingCkov(pCluLst->GetEntries()); //find the best reconstructed theta Cherenkov
153// FindRingGeom(thetaC,2);
154 pTrk->SetHMPIDsignal(thetaC); //store theta Cherenkov
155 pTrk->SetHMPIDchi2(fCkovSigma2); //store errors squared
76fd1a96 156 }
d3da6dc4 157
ffb1ac19 158 DeleteVars();
43400d2d 159}//CkovAngle()
d3da6dc4 160//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
a591e55f 161Bool_t AliHMPIDRecon::FindPhotCkov(Double_t cluX,Double_t cluY,Double_t &thetaCer,Double_t &phiCer)
d3da6dc4 162{
163// Finds Cerenkov angle for this photon candidate
164// Arguments: cluX,cluY - position of cadidate's cluster
a591e55f 165// Returns: Cerenkov angle
d3da6dc4 166
a591e55f 167 TVector3 dirCkov;
168
ffb1ac19 169 Double_t zRad= -0.5*fParam->RadThick()-0.5*fParam->WinThick(); //z position of middle of RAD
67a1c24c 170 TVector3 rad(fTrkPos.X(),fTrkPos.Y(),zRad); //impact point at middle of RAD
ffb1ac19 171 TVector3 pc(cluX,cluY,0.5*fParam->WinThick()+fParam->GapIdx()); //mip at PC
a591e55f 172 Double_t cluR = TMath::Sqrt((cluX-fTrkPos.X())*(cluX-fTrkPos.X())+
173 (cluY-fTrkPos.Y())*(cluY-fTrkPos.Y()));//ref. distance impact RAD-CLUSTER
67a1c24c 174 Double_t phi=(pc-rad).Phi(); //phi of photon
a591e55f 175
b4ad85e9 176 Double_t ckov1=0;
67a1c24c 177 Double_t ckov2=0.75+fTrkDir.Theta(); //start to find theta cerenkov in DRS
b4ad85e9 178 const Double_t kTol=0.01;
d3da6dc4 179 Int_t iIterCnt = 0;
180 while(1){
a591e55f 181 if(iIterCnt>=50) return kFALSE;
d3da6dc4 182 Double_t ckov=0.5*(ckov1+ckov2);
67a1c24c 183 dirCkov.SetMagThetaPhi(1,ckov,phi);
a591e55f 184 TVector2 posC=TraceForward(dirCkov); //trace photon with actual angles
185 Double_t dist=cluR-(posC-fTrkPos).Mod(); //get distance between trial point and cluster position
186 if(posC.X()==-999) dist = - 999; //total reflection problem
187 iIterCnt++; //counter step
b4ad85e9 188 if (dist> kTol) ckov1=ckov; //cluster @ larger ckov
d3da6dc4 189 else if(dist<-kTol) ckov2=ckov; //cluster @ smaller ckov
a591e55f 190 else{ //precision achived: ckov in DRS found
191 dirCkov.SetMagThetaPhi(1,ckov,phi); //
2d1a9b21 192 Lors2Trs(dirCkov,thetaCer,phiCer); //find ckov (in TRS:the effective Cherenkov angle!)
a591e55f 193 return kTRUE;
194 }
d3da6dc4 195 }
196}//FindPhotTheta()
197//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
a591e55f 198TVector2 AliHMPIDRecon::TraceForward(TVector3 dirCkov)const
d3da6dc4 199{
a591e55f 200 //Trace forward a photon from (x,y) up to PC
201 // Arguments: dirCkov photon vector in LORS
202 // Returns: pos of traced photon at PC
ffb1ac19 203
a591e55f 204 TVector2 pos(-999,-999);
67a1c24c 205 Double_t thetaCer = dirCkov.Theta();
ffb1ac19 206 if(thetaCer > TMath::ASin(1./fParam->GetRefIdx())) return pos; //total refraction on WIN-GAP boundary
207 Double_t zRad= -0.5*fParam->RadThick()-0.5*fParam->WinThick(); //z position of middle of RAD
208 TVector3 posCkov(fTrkPos.X(),fTrkPos.Y(),zRad); //RAD: photon position is track position @ middle of RAD
209 Propagate(dirCkov,posCkov, -0.5*fParam->WinThick()); //go to RAD-WIN boundary
210 Refract (dirCkov, fParam->GetRefIdx(),fParam->WinIdx()); //RAD-WIN refraction
211 Propagate(dirCkov,posCkov, 0.5*fParam->WinThick()); //go to WIN-GAP boundary
212 Refract (dirCkov, fParam->WinIdx(),fParam->GapIdx()); //WIN-GAP refraction
213 Propagate(dirCkov,posCkov,0.5*fParam->WinThick()+fParam->GapThick()); //go to PC
a591e55f 214 pos.Set(posCkov.X(),posCkov.Y());
215 return pos;
216}//TraceForward()
217//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2d1a9b21 218void AliHMPIDRecon::Lors2Trs(TVector3 dirCkov,Double_t &thetaCer,Double_t &phiCer)const
a591e55f 219{
220 //Theta Cerenkov reconstruction
2d1a9b21 221 // Arguments: dirCkov photon vector in LORS
222 // Returns: thetaCer of photon in TRS
223 // phiCer of photon in TRS
a591e55f 224// TVector3 dirTrk;
225// dirTrk.SetMagThetaPhi(1,fTrkDir.Theta(),fTrkDir.Phi());
226// Double_t thetaCer = TMath::ACos(dirCkov*dirTrk);
2d1a9b21 227 TRotation mtheta; mtheta.RotateY(-fTrkDir.Theta());
228 TRotation mphi; mphi.RotateZ(-fTrkDir.Phi());
a591e55f 229 TRotation mrot=mtheta*mphi;
230 TVector3 dirCkovTRS;
231 dirCkovTRS=mrot*dirCkov;
232 phiCer = dirCkovTRS.Phi(); //actual value of the phi of the photon
233 thetaCer= dirCkovTRS.Theta(); //actual value of thetaCerenkov of the photon
d3da6dc4 234}
235//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2d1a9b21 236void AliHMPIDRecon::Trs2Lors(TVector3 dirCkov,Double_t &thetaCer,Double_t &phiCer)const
237{
238 //Theta Cerenkov reconstruction
239 // Arguments: dirCkov photon vector in TRS
240 // Returns: thetaCer of photon in LORS
241 // phiCer of photon in LORS
242 TRotation mtheta; mtheta.RotateY(fTrkDir.Theta());
243 TRotation mphi; mphi.RotateZ(fTrkDir.Phi());
244 TRotation mrot=mphi*mtheta;
245 TVector3 dirCkovLORS;
246 dirCkovLORS=mrot*dirCkov;
247 phiCer = dirCkovLORS.Phi(); //actual value of the phi of the photon
248 thetaCer= dirCkovLORS.Theta(); //actual value of thetaCerenkov of the photon
249}
250//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
251void AliHMPIDRecon::FindRingGeom(Double_t ckovAng,Int_t level)
d3da6dc4 252{
4598109f 253// Find area covered in the PC acceptance
2d1a9b21 254// Arguments: ckovAng - cerenkov angle
255// level - precision in finding area and portion of ring accepted (multiple of 50)
d3da6dc4 256// Returns: area of the ring in cm^2 for given theta ckov
257
2d1a9b21 258 Int_t kN=50*level;
259 Int_t nPoints = 0;
afe12692 260 Double_t area=0;
2d1a9b21 261
4598109f 262 Bool_t first=kFALSE;
2d1a9b21 263 TVector2 pos1;
264
afe12692 265 for(Int_t i=0;i<kN;i++){
4598109f 266 if(!first) {
2d1a9b21 267 pos1=TracePhot(ckovAng,Double_t(TMath::TwoPi()*(i+1)/kN)); //find a good trace for the first photon
4598109f 268 if(pos1.X()==-999) continue; //no area: open ring
2d1a9b21 269 if(!fParam->IsInside(pos1.X(),pos1.Y(),0)) {
270 pos1 = IntWithEdge(fMipPos,pos1); // find the very first intersection...
271 } else {
272 if(!AliHMPIDParam::IsInDead(pos1.X(),pos1.Y())) nPoints++; //photon is accepted if not in dead zone
273 }
4598109f 274 first=kTRUE;
275 continue;
276 }
277 TVector2 pos2=TracePhot(ckovAng,Double_t(TMath::TwoPi()*(i+1)/kN)); //trace the next photon
278 if(pos2.X()==-999) continue; //no area: open ring
ffb1ac19 279 if(!fParam->IsInside(pos2.X(),pos2.Y(),0)) {
4598109f 280 pos2 = IntWithEdge(fMipPos,pos2);
2d1a9b21 281 } else {
282 if(!AliHMPIDParam::IsInDead(pos2.X(),pos2.Y())) nPoints++; //photon is accepted if not in dead zone
4598109f 283 }
284 area+=TMath::Abs((pos1-fMipPos).X()*(pos2-fMipPos).Y()-(pos1-fMipPos).Y()*(pos2-fMipPos).X()); //add area of the triangle...
285 pos1 = pos2;
d3da6dc4 286 }
2d1a9b21 287//--- find area and length of the ring;
288 fRingAcc = (Double_t)nPoints/(Double_t)kN;
7fc88c5e 289 area*=0.5;
2d1a9b21 290 fRingArea = area;
291}//FindRingGeom()
d3da6dc4 292//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
4598109f 293TVector2 AliHMPIDRecon::IntWithEdge(TVector2 p1,TVector2 p2)const
294{
295// It finds the intersection of the line for 2 points traced as photons
296// and the edge of a given PC
297// Arguments: 2 points obtained tracing the photons
298// Returns: intersection point with detector (PC) edges
299
4598109f 300 Double_t xmin = (p1.X()<p2.X())? p1.X():p2.X();
301 Double_t xmax = (p1.X()<p2.X())? p2.X():p1.X();
302 Double_t ymin = (p1.Y()<p2.Y())? p1.Y():p2.Y();
303 Double_t ymax = (p1.Y()<p2.Y())? p2.Y():p1.Y();
304
305 Double_t m = TMath::Tan((p2-p1).Phi());
306 TVector2 pint;
307 //intersection with low X
308 pint.Set((Double_t)(p1.X() + (0-p1.Y())/m),0.);
ffb1ac19 309 if(pint.X()>=0 && pint.X()<=fParam->SizeAllX() &&
4598109f 310 pint.X()>=xmin && pint.X()<=xmax &&
311 pint.Y()>=ymin && pint.Y()<=ymax) return pint;
312 //intersection with high X
ffb1ac19 313 pint.Set((Double_t)(p1.X() + (fParam->SizeAllY()-p1.Y())/m),(Double_t)(fParam->SizeAllY()));
314 if(pint.X()>=0 && pint.X()<=fParam->SizeAllX() &&
4598109f 315 pint.X()>=xmin && pint.X()<=xmax &&
316 pint.Y()>=ymin && pint.Y()<=ymax) return pint;
317 //intersection with left Y
318 pint.Set(0.,(Double_t)(p1.Y() + m*(0-p1.X())));
ffb1ac19 319 if(pint.Y()>=0 && pint.Y()<=fParam->SizeAllY() &&
4598109f 320 pint.Y()>=ymin && pint.Y()<=ymax &&
321 pint.X()>=xmin && pint.X()<=xmax) return pint;
322 //intersection with righ Y
ffb1ac19 323 pint.Set((Double_t)(fParam->SizeAllX()),(Double_t)(p1.Y() + m*(fParam->SizeAllX()-p1.X())));
324 if(pint.Y()>=0 && pint.Y()<=fParam->SizeAllY() &&
4598109f 325 pint.Y()>=ymin && pint.Y()<=ymax &&
326 pint.X()>=xmin && pint.X()<=xmax) return pint;
327 return p1;
328}//IntWithEdge()
329//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
d3da6dc4 330Double_t AliHMPIDRecon::FindRingCkov(Int_t)
331{
332// Loops on all Ckov candidates and estimates the best Theta Ckov for a ring formed by those candidates. Also estimates an error for that Theat Ckov
333// collecting errors for all single Ckov candidates thetas. (Assuming they are independent)
334// Arguments: iNclus- total number of clusters in chamber for background estimation
335// Return: best estimation of track Theta ckov
336
337 Double_t wei = 0.;
338 Double_t weightThetaCerenkov = 0.;
339
340 Double_t ckovMin=9999.,ckovMax=0.;
341 Double_t sigma2 = 0; //to collect error squared for this ring
342
343 for(Int_t i=0;i<fPhotCnt;i++){//candidates loop
344 if(fPhotFlag[i] == 2){
a591e55f 345 if(fPhotCkov[i]<ckovMin) ckovMin=fPhotCkov[i]; //find max and min Theta ckov from all candidates within probable window
d3da6dc4 346 if(fPhotCkov[i]>ckovMax) ckovMax=fPhotCkov[i];
a591e55f 347 weightThetaCerenkov += fPhotCkov[i]*fPhotWei[i];
348 wei += fPhotWei[i]; //collect weight as sum of all candidate weghts
d3da6dc4 349
3278403b 350 sigma2 += 1./fParam->Sigma2(fTrkDir.Theta(),fTrkDir.Phi(),fPhotCkov[i],fPhotPhi[i]);
d3da6dc4 351 }
352 }//candidates loop
353
354 if(sigma2>0) fCkovSigma2=1./sigma2;
355 else fCkovSigma2=1e10;
356
b4ad85e9 357 if(wei != 0.) weightThetaCerenkov /= wei; else weightThetaCerenkov = 0.;
d3da6dc4 358 return weightThetaCerenkov;
359}//FindCkovRing()
360//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
361Int_t AliHMPIDRecon::FlagPhot(Double_t ckov)
362{
363// Flag photon candidates if their individual ckov angle is inside the window around ckov angle returned by HoughResponse()
364// Arguments: ckov- value of most probable ckov angle for track as returned by HoughResponse()
365// Returns: number of photon candidates happened to be inside the window
366
a591e55f 367// Photon Flag: Flag = 0 initial set;
368// Flag = 1 good candidate (charge compatible with photon);
369// Flag = 2 photon used for the ring;
d3da6dc4 370
371 Int_t steps = (Int_t)((ckov )/ fDTheta); //how many times we need to have fDTheta to fill the distance between 0 and thetaCkovHough
372
373 Double_t tmin = (Double_t)(steps - 1)*fDTheta;
374 Double_t tmax = (Double_t)(steps)*fDTheta;
375 Double_t tavg = 0.5*(tmin+tmax);
376
377 tmin = tavg - 0.5*fWindowWidth; tmax = tavg + 0.5*fWindowWidth;
378
379 Int_t iInsideCnt = 0; //count photons which Theta ckov inside the window
380 for(Int_t i=0;i<fPhotCnt;i++){//photon candidates loop
afe12692 381 fPhotFlag[i] = 0;
d3da6dc4 382 if(fPhotCkov[i] >= tmin && fPhotCkov[i] <= tmax) {
383 fPhotFlag[i]=2;
384 iInsideCnt++;
385 }
386 }
387 return iInsideCnt;
388}//FlagPhot()
389//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
a591e55f 390TVector2 AliHMPIDRecon::TracePhot(Double_t ckovThe,Double_t ckovPhi)const
d3da6dc4 391{
392// Trace a single Ckov photon from emission point somewhere in radiator up to photocathode taking into account ref indexes of materials it travereses
ffb1ac19 393// Arguments: ckovThe,ckovPhi- photon ckov angles in TRS, [rad]
d3da6dc4 394// Returns: distance between photon point on PC and track projection
2d1a9b21 395
396 Double_t theta,phi;
397 TVector3 dirTRS,dirLORS;
398 dirTRS.SetMagThetaPhi(1,ckovThe,ckovPhi); //photon in TRS
399 Trs2Lors(dirTRS,theta,phi);
400 dirLORS.SetMagThetaPhi(1,theta,phi); //photon in LORS
401 return TraceForward(dirLORS); //now foward tracing
a591e55f 402}//TracePhot()
d3da6dc4 403//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
a591e55f 404void AliHMPIDRecon::Propagate(const TVector3 dir,TVector3 &pos,Double_t z)const
d3da6dc4 405{
406// Finds an intersection point between a line and XY plane shifted along Z.
407// Arguments: dir,pos - vector along the line and any point of the line
408// z - z coordinate of plain
409// Returns: none
410// On exit: pos is the position if this intesection if any
411 static TVector3 nrm(0,0,1);
412 TVector3 pnt(0,0,z);
413
414 TVector3 diff=pnt-pos;
415 Double_t sint=(nrm*diff)/(nrm*dir);
416 pos+=sint*dir;
417}//Propagate()
418//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
419void AliHMPIDRecon::Refract(TVector3 &dir,Double_t n1,Double_t n2)const
420{
421// Refract direction vector according to Snell law
422// Arguments:
423// n1 - ref idx of first substance
424// n2 - ref idx of second substance
425// Returns: none
426// On exit: dir is new direction
67a1c24c 427 Double_t sinref=(n1/n2)*TMath::Sin(dir.Theta());
76fd1a96 428 if(TMath::Abs(sinref)>1.) dir.SetXYZ(-999,-999,-999);
67a1c24c 429 else dir.SetTheta(TMath::ASin(sinref));
d3da6dc4 430}//Refract()
431//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
432Double_t AliHMPIDRecon::HoughResponse()
433{
434//
611e810d 435// fIdxMip = mipId;
436
d3da6dc4 437//
438 Double_t kThetaMax=0.75;
439 Int_t nChannels = (Int_t)(kThetaMax/fDTheta+0.5);
440 TH1D *phots = new TH1D("Rphot" ,"phots" ,nChannels,0,kThetaMax);
441 TH1D *photsw = new TH1D("RphotWeighted" ,"photsw" ,nChannels,0,kThetaMax);
442 TH1D *resultw = new TH1D("resultw","resultw" ,nChannels,0,kThetaMax);
443 Int_t nBin = (Int_t)(kThetaMax/fDTheta);
444 Int_t nCorrBand = (Int_t)(fWindowWidth/(2*fDTheta));
445
446 for (Int_t i=0; i< fPhotCnt; i++){//photon cadidates loop
447 Double_t angle = fPhotCkov[i]; if(angle<0||angle>kThetaMax) continue;
448 phots->Fill(angle);
449 Int_t bin = (Int_t)(0.5+angle/(fDTheta));
450 Double_t weight=1.;
451 if(fIsWEIGHT){
afe12692 452 Double_t lowerlimit = ((Double_t)bin)*fDTheta - 0.5*fDTheta; Double_t upperlimit = ((Double_t)bin)*fDTheta + 0.5*fDTheta;
2d1a9b21 453 FindRingGeom(lowerlimit);
454 Double_t areaLow = GetRingArea();
455 FindRingGeom(upperlimit);
456 Double_t areaHigh = GetRingArea();
457 Double_t diffArea = areaHigh - areaLow;
d3da6dc4 458 if(diffArea>0) weight = 1./diffArea;
459 }
460 photsw->Fill(angle,weight);
461 fPhotWei[i]=weight;
462 }//photon candidates loop
463
464 for (Int_t i=1; i<=nBin;i++){
465 Int_t bin1= i-nCorrBand;
466 Int_t bin2= i+nCorrBand;
467 if(bin1<1) bin1=1;
468 if(bin2>nBin)bin2=nBin;
469 Double_t sumPhots=phots->Integral(bin1,bin2);
470 if(sumPhots<3) continue; // if less then 3 photons don't trust to this ring
471 Double_t sumPhotsw=photsw->Integral(bin1,bin2);
472 resultw->Fill((Double_t)((i+0.5)*fDTheta),sumPhotsw);
473 }
474// evaluate the "BEST" theta ckov as the maximum value of histogramm
475 Double_t *pVec = resultw->GetArray();
476 Int_t locMax = TMath::LocMax(nBin,pVec);
3ebd8038 477 delete phots;delete photsw;delete resultw; // Reset and delete objects
d3da6dc4 478
479 return (Double_t)(locMax*fDTheta+0.5*fDTheta); //final most probable track theta ckov
480}//HoughResponse()
481//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++