1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
16 // PID Response class for the TRD detector
17 // Based on 1D Likelihood approach
18 // Calculation of probabilities using Bayesian approach
19 // Attention: This method is only used to separate electrons from pions
22 // Markus Fasel <M.Fasel@gsi.de>
23 // Anton Andronic <A.Andronic@gsi.de>
27 #include <TDirectory.h>
32 #include <TObjArray.h>
39 #include "AliTRDPIDResponseObject.h"
40 #include "AliTRDPIDResponse.h"
41 //#include "AliTRDTKDInterpolator.h"
42 #include "AliTRDNDFast.h"
44 ClassImp(AliTRDPIDResponse)
46 //____________________________________________________________
47 AliTRDPIDResponse::AliTRDPIDResponse():
49 ,fkPIDResponseObject(NULL)
50 ,fGainNormalisationFactor(1.)
53 // Default constructor
57 //____________________________________________________________
58 AliTRDPIDResponse::AliTRDPIDResponse(const AliTRDPIDResponse &ref):
60 ,fkPIDResponseObject(NULL)
61 ,fGainNormalisationFactor(ref.fGainNormalisationFactor)
68 //____________________________________________________________
69 AliTRDPIDResponse &AliTRDPIDResponse::operator=(const AliTRDPIDResponse &ref){
71 // Assignment operator
73 if(this == &ref) return *this;
76 TObject::operator=(ref);
77 fGainNormalisationFactor = ref.fGainNormalisationFactor;
78 fkPIDResponseObject = ref.fkPIDResponseObject;
83 //____________________________________________________________
84 AliTRDPIDResponse::~AliTRDPIDResponse(){
88 if(IsOwner()) delete fkPIDResponseObject;
91 //____________________________________________________________
92 Bool_t AliTRDPIDResponse::Load(const Char_t * filename){
94 // Load References into the toolkit
96 AliDebug(1, "Loading reference histos from root file");
97 TDirectory *owd = gDirectory;// store old working directory
100 filename = Form("%s/STEER/LQ1dRef_v1.root",gSystem->ExpandPathName("$ALICE_ROOT"));
101 TFile *in = TFile::Open(filename);
103 AliError("Ref file not available.");
108 fkPIDResponseObject = dynamic_cast<const AliTRDPIDResponseObject *>(in->Get("TRDPIDResponse")->Clone());
109 in->Close(); delete in;
111 SetBit(kIsOwner, kTRUE);
112 AliDebug(2, Form("Successfully loaded References for %d Momentum bins", fkPIDResponseObject->GetNumberOfMomentumBins()));
116 //____________________________________________________________
117 Int_t AliTRDPIDResponse::GetResponse(Int_t n, const Double_t * const dedx, const Float_t * const p, Double_t prob[AliPID::kSPECIES],ETRDPIDMethod PIDmethod,Bool_t kNorm) const
120 // Calculate TRD likelihood values for the track based on dedx and
121 // momentum values. The likelihoods are calculated by query the
122 // reference data depending on the PID method selected
125 // n - number of dedx slices/chamber
126 // dedx - array of dedx slices organized layer wise
127 // p - array of momentum measurements organized layer wise
130 // prob - probabilities allocated by TRD for particle specis
131 // kNorm - switch to normalize probabilities to 1. By default true. If false return not normalized prob.
134 // number of tracklets used for PID, 0 if no PID
136 AliDebug(3,Form(" Response for PID method: %d",PIDmethod));
139 if(!fkPIDResponseObject){
140 AliDebug(3,"Missing reference data. PID calculation not possible.");
144 for(Int_t is(AliPID::kSPECIES); is--;) prob[is]=.2;
145 Double_t prLayer[AliPID::kSPECIES];
146 Double_t dE[10], s(0.);
147 Int_t ntrackletsPID=0;
148 for(Int_t il(kNlayer); il--;){
149 memset(prLayer, 0, AliPID::kSPECIES*sizeof(Double_t));
150 if(!CookdEdx(n, &dedx[il*n], &dE[0],PIDmethod)) continue;
153 for(Int_t is(AliPID::kSPECIES); is--;){
154 //if((PIDmethod==kLQ2D)&&(!(is==0||is==2)))continue;
155 if((dE[0] > 0.) && (p[il] > 0.)) prLayer[is] = GetProbabilitySingleLayer(is, p[il], &dE[0],PIDmethod);
156 AliDebug(3, Form("Probability for Species %d in Layer %d: %e", is, il, prLayer[is]));
157 if(prLayer[is]<1.e-30){
158 AliDebug(2, Form("Null for species %d species prob layer[%d].",is,il));
168 AliDebug(2, Form("Null all species prob layer[%d].", il));
171 for(Int_t is(AliPID::kSPECIES); is--;){
172 if(kNorm) prLayer[is] /= s;
173 prob[is] *= prLayer[is];
177 if(!kNorm) return ntrackletsPID;
180 for(Int_t is(AliPID::kSPECIES); is--;) s+=prob[is];
182 AliDebug(2, "Null total prob.");
185 for(Int_t is(AliPID::kSPECIES); is--;) prob[is]/=s;
186 return ntrackletsPID;
189 //____________________________________________________________
190 Double_t AliTRDPIDResponse::GetProbabilitySingleLayer(Int_t species, Double_t plocal, Double_t *dEdx,ETRDPIDMethod PIDmethod) const {
192 // Get the non-normalized probability for a certain particle species as coming
193 // from the reference histogram
194 // Interpolation between momentum bins
196 AliDebug(1, Form("Make Probability for Species %d with Momentum %f", species, plocal));
198 Double_t probLayer = 0.;
200 Float_t pLower, pUpper;
202 AliTRDNDFast *refUpper = dynamic_cast<AliTRDNDFast *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,PIDmethod)),
203 *refLower = dynamic_cast<AliTRDNDFast *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,PIDmethod));
205 // Do Interpolation exept for underflow and overflow
206 if(refLower && refUpper){
207 Double_t probLower = refLower->Eval(dEdx);
208 Double_t probUpper = refUpper->Eval(dEdx);
210 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
213 probLayer = refLower->Eval(dEdx);
216 probLayer = refUpper->Eval(dEdx);
218 AliError("No references available");
220 AliDebug(1, Form("Eval 1D dEdx %f Probability %e", dEdx[0],probLayer));
224 /* old implementation
231 if(species==0||species==2){ // references only for electrons and pions
233 Double_t point[kNslicesLQ2D];
234 for(Int_t idim=0;idim<kNslicesLQ2D;idim++){point[idim]=dEdx[idim];}
236 AliTRDTKDInterpolator *refUpper = dynamic_cast<AliTRDTKDInterpolator *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,kLQ2D)),
237 *refLower = dynamic_cast<AliTRDTKDInterpolator *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,kLQ2D));
238 // Do Interpolation exept for underflow and overflow
239 if(refLower && refUpper){
240 Double_t probLower=0,probUpper=0;
241 refLower->Eval(point,probLower,error);
242 refUpper->Eval(point,probUpper,error);
243 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
246 refLower->Eval(point,probLayer,error);
249 refUpper->Eval(point,probLayer,error);
251 AliError("No references available");
253 AliDebug(2,Form("Eval 2D Q0 %f Q1 %f P %e Err %e",point[0],point[1],probLayer,error));
259 TH1 *refUpper = dynamic_cast<TH1 *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,kLQ1D)),
260 *refLower = dynamic_cast<TH1 *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,kLQ1D));
261 // Do Interpolation exept for underflow and overflow
262 if(refLower && refUpper){
263 Double_t probLower = refLower->GetBinContent(refLower->GetXaxis()->FindBin(dEdx[0]));
264 Double_t probUpper = refUpper->GetBinContent(refUpper->GetXaxis()->FindBin(dEdx[0]));
266 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
269 probLayer = refLower->GetBinContent(refLower->GetXaxis()->FindBin(dEdx[0]));
272 probLayer = refUpper->GetBinContent(refUpper->GetXaxis()->FindBin(dEdx[0]));
274 AliError("No references available");
276 AliDebug(1, Form("Eval 1D dEdx %f Probability %e", dEdx[0],probLayer));
287 //____________________________________________________________
288 void AliTRDPIDResponse::SetOwner(){
290 // Make Deep Copy of the Reference Histograms
292 if(!fkPIDResponseObject || IsOwner()) return;
293 const AliTRDPIDResponseObject *tmp = fkPIDResponseObject;
294 fkPIDResponseObject = dynamic_cast<const AliTRDPIDResponseObject *>(tmp->Clone());
295 SetBit(kIsOwner, kTRUE);
298 //____________________________________________________________
299 Bool_t AliTRDPIDResponse::CookdEdx(Int_t nSlice, const Double_t * const in, Double_t *out,ETRDPIDMethod PIDmethod) const
310 for(Int_t islice = 0; islice < nSlice; islice++){
311 if(in[islice]<=0){out[0]=0;out[1]=0;return kFALSE;} // Require that all slices are filled
312 if(islice<fkPIDResponseObject->GetNSlicesQ0())out[0]+= in[islice];
313 else out[1]+= in[islice];
315 // normalize signal to number of slices
316 out[0]*=1./Double_t(fkPIDResponseObject->GetNSlicesQ0());
317 out[1]*=1./Double_t(nSlice-fkPIDResponseObject->GetNSlicesQ0());
318 if(out[0] < 1e-6) return kFALSE;
319 AliDebug(3,Form("CookdEdx Q0 %f Q1 %f",out[0],out[1]));
323 for(Int_t islice = 0; islice < nSlice; islice++)
324 if(in[islice] > 0) out[0] += in[islice] * fGainNormalisationFactor; // Protect against negative values for slices having no dE/dx information
325 out[0]*=1./Double_t(nSlice);
326 if(out[0] < 1e-6) return kFALSE;
327 AliDebug(3,Form("CookdEdx dEdx %f",out[0]));
336 //____________________________________________________________
337 Bool_t AliTRDPIDResponse::IdentifiedAsElectron(Int_t nTracklets, const Double_t *like, Double_t p, Double_t level,Double_t centrality,ETRDPIDMethod PIDmethod) const {
339 // Check whether particle is identified as electron assuming a certain electron efficiency level
340 // Only electron and pion hypothesis is taken into account
343 // Number of tracklets
346 // Electron efficiency level
348 // If the function fails when the params are not accessible, the function returns true
350 if(!fkPIDResponseObject){
351 AliDebug(3,"No PID Param object available");
354 Double_t probEle = like[AliPID::kElectron]/(like[AliPID::kElectron] + like[AliPID::kPion]);
356 if(!fkPIDResponseObject->GetThresholdParameters(nTracklets, level, params,centrality,PIDmethod)){
357 AliError("No Params found for the given configuration");
360 Double_t threshold = 1. - params[0] - params[1] * p - params[2] * TMath::Exp(-params[3] * p);
361 if(probEle > TMath::Max(TMath::Min(threshold, 0.99), 0.2)) return kTRUE; // truncate the threshold upperwards to 0.999 and lowerwards to 0.2 and exclude unphysical values
365 //____________________________________________________________
366 Bool_t AliTRDPIDResponse::SetPIDResponseObject(const AliTRDPIDResponseObject * obj){
368 fkPIDResponseObject = obj;
369 if((AliLog::GetDebugLevel("",IsA()->GetName()))>0)fkPIDResponseObject->Print("");