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"
43 ClassImp(AliTRDPIDResponse)
45 //____________________________________________________________
46 AliTRDPIDResponse::AliTRDPIDResponse():
48 ,fkPIDResponseObject(NULL)
49 ,fGainNormalisationFactor(1.)
52 // Default constructor
56 //____________________________________________________________
57 AliTRDPIDResponse::AliTRDPIDResponse(const AliTRDPIDResponse &ref):
59 ,fkPIDResponseObject(NULL)
60 ,fGainNormalisationFactor(ref.fGainNormalisationFactor)
67 //____________________________________________________________
68 AliTRDPIDResponse &AliTRDPIDResponse::operator=(const AliTRDPIDResponse &ref){
70 // Assignment operator
72 if(this == &ref) return *this;
75 TObject::operator=(ref);
76 fGainNormalisationFactor = ref.fGainNormalisationFactor;
77 fkPIDResponseObject = ref.fkPIDResponseObject;
82 //____________________________________________________________
83 AliTRDPIDResponse::~AliTRDPIDResponse(){
87 if(IsOwner()) delete fkPIDResponseObject;
90 //____________________________________________________________
91 Bool_t AliTRDPIDResponse::Load(const Char_t * filename){
93 // Load References into the toolkit
95 AliDebug(1, "Loading reference histos from root file");
96 TDirectory *owd = gDirectory;// store old working directory
99 filename = Form("%s/STEER/LQ1dRef_v1.root",gSystem->ExpandPathName("$ALICE_ROOT"));
100 TFile *in = TFile::Open(filename);
102 AliError("Ref file not available.");
107 fkPIDResponseObject = dynamic_cast<const AliTRDPIDResponseObject *>(in->Get("TRDPIDResponse")->Clone());
108 in->Close(); delete in;
110 SetBit(kIsOwner, kTRUE);
111 AliDebug(2, Form("Successfully loaded References for %d Momentum bins", fkPIDResponseObject->GetNumberOfMomentumBins()));
115 //____________________________________________________________
116 Bool_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
119 // Calculate TRD likelihood values for the track based on dedx and
120 // momentum values. The likelihoods are calculated by query the
121 // reference data depending on the PID method selected
124 // n - number of dedx slices/chamber
125 // dedx - array of dedx slices organized layer wise
126 // p - array of momentum measurements organized layer wise
129 // prob - probabilities allocated by TRD for particle specis
130 // kNorm - switch to normalize probabilities to 1. By default true. If false return not normalized prob.
133 // true if calculation success
135 AliDebug(3,Form(" Response for PID method: %d",PIDmethod));
138 if(!fkPIDResponseObject){
139 AliWarning("Missing reference data. PID calculation not possible.");
143 for(Int_t is(AliPID::kSPECIES); is--;) prob[is]=.2;
144 Double_t prLayer[AliPID::kSPECIES];
145 Double_t dE[10], s(0.);
146 for(Int_t il(kNlayer); il--;){
147 memset(prLayer, 0, AliPID::kSPECIES*sizeof(Double_t));
148 if(!CookdEdx(n, &dedx[il*n], &dE[0],PIDmethod)) continue;
152 for(Int_t is(AliPID::kSPECIES); is--;){
153 if((PIDmethod==kLQ2D)&&(!(is==0||is==2)))continue;
154 if((dE[0] > 0.) && (p[il] > 0.)) prLayer[is] = GetProbabilitySingleLayer(is, p[il], &dE[0],PIDmethod);
155 AliDebug(3, Form("Probability for Species %d in Layer %d: %e", is, il, prLayer[is]));
156 if(prLayer[is]<1.e-30){
157 AliDebug(2, Form("Null for species %d species prob layer[%d].",is,il));
167 AliDebug(2, Form("Null all species prob layer[%d].", il));
170 for(Int_t is(AliPID::kSPECIES); is--;){
171 if(kNorm) prLayer[is] /= s;
172 prob[is] *= prLayer[is];
175 if(!kNorm) return kTRUE;
178 for(Int_t is(AliPID::kSPECIES); is--;) s+=prob[is];
180 AliDebug(2, "Null total prob.");
183 for(Int_t is(AliPID::kSPECIES); is--;) prob[is]/=s;
187 //____________________________________________________________
188 Double_t AliTRDPIDResponse::GetProbabilitySingleLayer(Int_t species, Double_t plocal, Double_t *dEdx,ETRDPIDMethod PIDmethod) const {
190 // Get the non-normalized probability for a certain particle species as coming
191 // from the reference histogram
192 // Interpolation between momentum bins
194 AliDebug(1, Form("Make Probability for Species %d with Momentum %f", species, plocal));
196 Double_t probLayer = 0.;
197 Float_t pLower, pUpper;
204 if(species==0||species==2){ // references only for electrons and pions
206 Double_t point[kNslicesLQ2D];
207 for(Int_t idim=0;idim<kNslicesLQ2D;idim++){point[idim]=dEdx[idim];}
209 AliTRDTKDInterpolator *refLower = dynamic_cast<AliTRDTKDInterpolator*>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,kLQ2D));
212 refLower->Eval(point,probLayer,error);
215 AliError("No references available");
217 AliDebug(2,Form("Eval 2D Q0 %f Q1 %f P %e Err %e",point[0],point[1],probLayer,error));
223 TH1 *refUpper = dynamic_cast<TH1 *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,kLQ1D)),
224 *refLower = dynamic_cast<TH1 *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,kLQ1D));
225 // Do Interpolation exept for underflow and overflow
226 if(refLower && refUpper){
227 Double_t probLower = refLower->GetBinContent(refLower->GetXaxis()->FindBin(dEdx[0]));
228 Double_t probUpper = refUpper->GetBinContent(refUpper->GetXaxis()->FindBin(dEdx[0]));
230 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
233 probLayer = refLower->GetBinContent(refLower->GetXaxis()->FindBin(dEdx[0]));
236 probLayer = refUpper->GetBinContent(refUpper->GetXaxis()->FindBin(dEdx[0]));
238 AliError("No references available");
240 AliDebug(1, Form("Eval 1D dEdx %f Probability %e", dEdx[0],probLayer));
249 //____________________________________________________________
250 void AliTRDPIDResponse::SetOwner(){
252 // Make Deep Copy of the Reference Histograms
254 if(!fkPIDResponseObject || IsOwner()) return;
255 const AliTRDPIDResponseObject *tmp = fkPIDResponseObject;
256 fkPIDResponseObject = dynamic_cast<const AliTRDPIDResponseObject *>(tmp->Clone());
257 SetBit(kIsOwner, kTRUE);
260 //____________________________________________________________
261 Bool_t AliTRDPIDResponse::CookdEdx(Int_t nSlice, const Double_t * const in, Double_t *out,ETRDPIDMethod PIDmethod) const
272 for(Int_t islice = 0; islice < nSlice; islice++){
273 if(islice<fkPIDResponseObject->GetNSlicesQ0())out[0]+= in[islice];
274 else out[1]+= in[islice];
276 if(out[0] < 1e-6) return kFALSE;
277 AliDebug(3,Form("CookdEdx Q0 %f Q1 %f",out[0],out[1]));
281 for(Int_t islice = 0; islice < nSlice; islice++)
282 if(in[islice] > 0) out[0] += in[islice] * fGainNormalisationFactor; // Protect against negative values for slices having no dE/dx information
283 if(out[0] < 1e-6) return kFALSE;
284 AliDebug(3,Form("CookdEdx dEdx %f",out[0]));
293 //____________________________________________________________
294 Bool_t AliTRDPIDResponse::IdentifiedAsElectron(Int_t nTracklets, const Double_t *like, Double_t p, Double_t level,Double_t centrality,ETRDPIDMethod PIDmethod) const {
296 // Check whether particle is identified as electron assuming a certain electron efficiency level
297 // Only electron and pion hypothesis is taken into account
300 // Number of tracklets
303 // Electron efficiency level
305 // If the function fails when the params are not accessible, the function returns true
307 if(!fkPIDResponseObject){
308 AliError("No PID Param object available");
311 Double_t probEle = like[AliPID::kElectron]/(like[AliPID::kElectron] + like[AliPID::kPion]);
313 if(!fkPIDResponseObject->GetThresholdParameters(nTracklets, level, params,centrality,PIDmethod)){
314 AliError("No Params found for the given configuration");
317 Double_t threshold = 1. - params[0] - params[1] * p - params[2] * TMath::Exp(-params[3] * p);
318 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
322 //____________________________________________________________
323 Bool_t AliTRDPIDResponse::SetPIDResponseObject(const AliTRDPIDResponseObject * obj){
325 fkPIDResponseObject = obj;
326 if((AliLog::GetDebugLevel("",IsA()->GetName()))>0)fkPIDResponseObject->Print("");