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 "AliVTrack.h"
41 #include "AliTRDPIDResponseObject.h"
42 #include "AliTRDPIDResponse.h"
43 //#include "AliTRDTKDInterpolator.h"
44 #include "AliTRDNDFast.h"
45 #include "AliTRDdEdxParams.h"
47 ClassImp(AliTRDPIDResponse)
49 //____________________________________________________________
50 AliTRDPIDResponse::AliTRDPIDResponse():
52 ,fkPIDResponseObject(NULL)
53 ,fkTRDdEdxParams(NULL)
54 ,fGainNormalisationFactor(1.)
57 // Default constructor
61 //____________________________________________________________
62 AliTRDPIDResponse::AliTRDPIDResponse(const AliTRDPIDResponse &ref):
64 ,fkPIDResponseObject(NULL)
65 ,fkTRDdEdxParams(NULL)
66 ,fGainNormalisationFactor(ref.fGainNormalisationFactor)
73 //____________________________________________________________
74 AliTRDPIDResponse &AliTRDPIDResponse::operator=(const AliTRDPIDResponse &ref){
76 // Assignment operator
78 if(this == &ref) return *this;
81 TObject::operator=(ref);
82 fGainNormalisationFactor = ref.fGainNormalisationFactor;
83 fkPIDResponseObject = ref.fkPIDResponseObject;
84 fkTRDdEdxParams = ref.fkTRDdEdxParams;
89 //____________________________________________________________
90 AliTRDPIDResponse::~AliTRDPIDResponse(){
95 delete fkPIDResponseObject;
96 delete fkTRDdEdxParams;
100 //____________________________________________________________
101 Bool_t AliTRDPIDResponse::Load(const Char_t * filename){
103 // Load References into the toolkit
105 AliDebug(1, "Loading reference histos from root file");
106 TDirectory *owd = gDirectory;// store old working directory
109 filename = Form("%s/STEER/LQ1dRef_v1.root",gSystem->ExpandPathName("$ALICE_ROOT"));
110 TFile *in = TFile::Open(filename);
112 AliError("Ref file not available.");
117 fkPIDResponseObject = dynamic_cast<const AliTRDPIDResponseObject *>(in->Get("TRDPIDResponse")->Clone());
118 in->Close(); delete in;
120 SetBit(kIsOwner, kTRUE);
121 AliDebug(2, Form("Successfully loaded References for %d Momentum bins", fkPIDResponseObject->GetNumberOfMomentumBins()));
127 //____________________________________________________________
128 Double_t AliTRDPIDResponse::GetNumberOfSigmas(const AliVTrack *track, AliPID::EParticleType type) const
131 //calculate the TRD nSigma
134 const Double_t badval = -9999;
135 Double_t info[5]; for(int i=0; i<5; i++){info[i]=badval;}
137 const Double_t delta = GetSignalDelta(track, type, kFALSE, info);
139 const Double_t mean = info[0];
140 const Double_t res = info[1];
145 const Double_t sigma = mean*res;
146 const Double_t eps = 1e-12;
147 return delta/(sigma + eps);
150 //____________________________________________________________
151 Double_t AliTRDPIDResponse::GetSignalDelta( const AliVTrack* track, AliPID::EParticleType type, Bool_t ratio/*=kFALSE*/, Double_t *info/*=0x0*/) const
154 //calculate the TRD signal difference w.r.t. the expected
155 //output other information in info[]
158 const Double_t badval = -9999;
164 Double_t pTRD = -999;
165 for(Int_t ich=0; ich<6; ich++){
166 pTRD = track->GetTRDmomentum(ich);
174 if(!fkTRDdEdxParams){
175 AliError("fkTRDdEdxParams null");
179 const Double_t nch = track->GetTRDNchamberdEdx();
180 const Double_t ncls = track->GetTRDNclusterdEdx();
182 const TVectorF meanvec = fkTRDdEdxParams->GetMeanParameter(type, nch, ncls);
183 if(meanvec.GetNrows()==0){
187 const TVectorF resvec = fkTRDdEdxParams->GetSigmaParameter(type, nch, ncls);
188 if(resvec.GetNrows()==0){
192 const Float_t *meanpar = meanvec.GetMatrixArray();
193 const Float_t *respar = resvec.GetMatrixArray();
195 //============================================================================================<<<<<<<<<<<<<
197 const Double_t bg = pTRD/AliPID::ParticleMass(type);
198 const Double_t expsig = MeandEdxTR(&bg, meanpar);
202 info[1]= ResolutiondEdxTR(&ncls, respar);
205 const Double_t eps = 1e-10;
208 return track->GetTRDsignal()/(expsig + eps);
211 return track->GetTRDsignal() - expsig;
216 Double_t AliTRDPIDResponse::ResolutiondEdxTR(const Double_t * xx, const Float_t * par)
223 const Double_t ncls = xx[0];
225 return par[0]+par[1]*TMath::Power(ncls, par[2]);
228 Double_t AliTRDPIDResponse::MeandEdxTR(const Double_t * xx, const Float_t * pin)
231 //ALEPH+LOGISTIC parametrization for dEdx+TR, in unit of MIP
236 for(int ii=0; ii<3; ii++){
239 return MeanTR(xx,ptr) + MeandEdx(xx,&(pin[3]));
242 Double_t AliTRDPIDResponse::MeanTR(const Double_t * xx, const Float_t * par)
245 //LOGISTIC parametrization for TR, in unit of MIP
249 const Double_t bg = xx[0];
250 const Double_t gamma = sqrt(1+bg*bg);
252 const Double_t p0 = TMath::Abs(par[1]);
253 const Double_t p1 = TMath::Abs(par[2]);
254 const Double_t p2 = TMath::Abs(par[3]);
256 const Double_t zz = TMath::Log(gamma);
257 const Double_t tryield = p0/( 1 + TMath::Exp(-p1*(zz-p2)) );
259 return par[0]+tryield;
262 Double_t AliTRDPIDResponse::MeandEdx(const Double_t * xx, const Float_t * par)
265 //ALEPH parametrization for dEdx
269 const Double_t bg = xx[0];
270 const Double_t beta = bg/TMath::Sqrt(1.+ bg*bg);
272 const Double_t p0 = TMath::Abs(par[0]);
273 const Double_t p1 = TMath::Abs(par[1]);
275 const Double_t p2 = TMath::Abs(par[2]);
277 const Double_t p3 = TMath::Abs(par[3]);
278 const Double_t p4 = TMath::Abs(par[4]);
280 const Double_t aa = TMath::Power(beta, p3);
282 const Double_t bb = TMath::Log( p2 + TMath::Power(1./bg, p4) );
284 return (p1-aa-bb)*p0/aa;
289 //____________________________________________________________
290 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
293 // Calculate TRD likelihood values for the track based on dedx and
294 // momentum values. The likelihoods are calculated by query the
295 // reference data depending on the PID method selected
298 // n - number of dedx slices/chamber
299 // dedx - array of dedx slices organized layer wise
300 // p - array of momentum measurements organized layer wise
303 // prob - probabilities allocated by TRD for particle specis
304 // kNorm - switch to normalize probabilities to 1. By default true. If false return not normalized prob.
307 // number of tracklets used for PID, 0 if no PID
309 AliDebug(3,Form(" Response for PID method: %d",PIDmethod));
312 if(!fkPIDResponseObject){
313 AliDebug(3,"Missing reference data. PID calculation not possible.");
317 for(Int_t is(AliPID::kSPECIES); is--;) prob[is]=.2;
318 Double_t prLayer[AliPID::kSPECIES];
319 Double_t dE[10], s(0.);
320 Int_t ntrackletsPID=0;
321 for(Int_t il(kNlayer); il--;){
322 memset(prLayer, 0, AliPID::kSPECIES*sizeof(Double_t));
323 if(!CookdEdx(n, &dedx[il*n], &dE[0],PIDmethod)) continue;
326 for(Int_t is(AliPID::kSPECIES); is--;){
327 //if((PIDmethod==kLQ2D)&&(!(is==0||is==2)))continue;
328 if((dE[0] > 0.) && (p[il] > 0.)) prLayer[is] = GetProbabilitySingleLayer(is, p[il], &dE[0],PIDmethod);
329 AliDebug(3, Form("Probability for Species %d in Layer %d: %e", is, il, prLayer[is]));
330 if(prLayer[is]<1.e-30){
331 AliDebug(2, Form("Null for species %d species prob layer[%d].",is,il));
341 AliDebug(2, Form("Null all species prob layer[%d].", il));
344 for(Int_t is(AliPID::kSPECIES); is--;){
345 if(kNorm) prLayer[is] /= s;
346 prob[is] *= prLayer[is];
350 if(!kNorm) return ntrackletsPID;
353 for(Int_t is(AliPID::kSPECIES); is--;) s+=prob[is];
355 AliDebug(2, "Null total prob.");
358 for(Int_t is(AliPID::kSPECIES); is--;) prob[is]/=s;
359 return ntrackletsPID;
362 //____________________________________________________________
363 Double_t AliTRDPIDResponse::GetProbabilitySingleLayer(Int_t species, Double_t plocal, Double_t *dEdx,ETRDPIDMethod PIDmethod) const {
365 // Get the non-normalized probability for a certain particle species as coming
366 // from the reference histogram
367 // Interpolation between momentum bins
369 AliDebug(1, Form("Make Probability for Species %d with Momentum %f", species, plocal));
371 Double_t probLayer = 0.;
373 Float_t pLower, pUpper;
375 AliTRDNDFast *refUpper = dynamic_cast<AliTRDNDFast *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,PIDmethod)),
376 *refLower = dynamic_cast<AliTRDNDFast *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,PIDmethod));
378 // Do Interpolation exept for underflow and overflow
379 if(refLower && refUpper){
380 Double_t probLower = refLower->Eval(dEdx);
381 Double_t probUpper = refUpper->Eval(dEdx);
383 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
386 probLayer = refLower->Eval(dEdx);
389 probLayer = refUpper->Eval(dEdx);
391 AliError("No references available");
393 AliDebug(1, Form("Eval 1D dEdx %f Probability %e", dEdx[0],probLayer));
397 /* old implementation
404 if(species==0||species==2){ // references only for electrons and pions
406 Double_t point[kNslicesLQ2D];
407 for(Int_t idim=0;idim<kNslicesLQ2D;idim++){point[idim]=dEdx[idim];}
409 AliTRDTKDInterpolator *refUpper = dynamic_cast<AliTRDTKDInterpolator *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,kLQ2D)),
410 *refLower = dynamic_cast<AliTRDTKDInterpolator *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,kLQ2D));
411 // Do Interpolation exept for underflow and overflow
412 if(refLower && refUpper){
413 Double_t probLower=0,probUpper=0;
414 refLower->Eval(point,probLower,error);
415 refUpper->Eval(point,probUpper,error);
416 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
419 refLower->Eval(point,probLayer,error);
422 refUpper->Eval(point,probLayer,error);
424 AliError("No references available");
426 AliDebug(2,Form("Eval 2D Q0 %f Q1 %f P %e Err %e",point[0],point[1],probLayer,error));
432 TH1 *refUpper = dynamic_cast<TH1 *>(fkPIDResponseObject->GetUpperReference((AliPID::EParticleType)species, plocal, pUpper,kLQ1D)),
433 *refLower = dynamic_cast<TH1 *>(fkPIDResponseObject->GetLowerReference((AliPID::EParticleType)species, plocal, pLower,kLQ1D));
434 // Do Interpolation exept for underflow and overflow
435 if(refLower && refUpper){
436 Double_t probLower = refLower->GetBinContent(refLower->GetXaxis()->FindBin(dEdx[0]));
437 Double_t probUpper = refUpper->GetBinContent(refUpper->GetXaxis()->FindBin(dEdx[0]));
439 probLayer = probLower + (probUpper - probLower)/(pUpper-pLower) * (plocal - pLower);
442 probLayer = refLower->GetBinContent(refLower->GetXaxis()->FindBin(dEdx[0]));
445 probLayer = refUpper->GetBinContent(refUpper->GetXaxis()->FindBin(dEdx[0]));
447 AliError("No references available");
449 AliDebug(1, Form("Eval 1D dEdx %f Probability %e", dEdx[0],probLayer));
460 //____________________________________________________________
461 void AliTRDPIDResponse::SetOwner(){
463 // Make Deep Copy of the Reference Histograms
465 if(!fkPIDResponseObject || IsOwner()) return;
466 const AliTRDPIDResponseObject *tmp = fkPIDResponseObject;
467 fkPIDResponseObject = dynamic_cast<const AliTRDPIDResponseObject *>(tmp->Clone());
468 SetBit(kIsOwner, kTRUE);
471 //____________________________________________________________
472 Bool_t AliTRDPIDResponse::CookdEdx(Int_t nSlice, const Double_t * const in, Double_t *out,ETRDPIDMethod PIDmethod) const
483 for(Int_t islice = 0; islice < nSlice; islice++){
484 if(in[islice]<=0){out[0]=0;out[1]=0;return kFALSE;} // Require that all slices are filled
485 if(islice<fkPIDResponseObject->GetNSlicesQ0())out[0]+= in[islice];
486 else out[1]+= in[islice];
488 // normalize signal to number of slices
489 out[0]*=1./Double_t(fkPIDResponseObject->GetNSlicesQ0());
490 out[1]*=1./Double_t(nSlice-fkPIDResponseObject->GetNSlicesQ0());
491 if(out[0] < 1e-6) return kFALSE;
492 AliDebug(3,Form("CookdEdx Q0 %f Q1 %f",out[0],out[1]));
496 for(Int_t islice = 0; islice < nSlice; islice++)
497 if(in[islice] > 0) out[0] += in[islice] * fGainNormalisationFactor; // Protect against negative values for slices having no dE/dx information
498 out[0]*=1./Double_t(nSlice);
499 if(out[0] < 1e-6) return kFALSE;
500 AliDebug(3,Form("CookdEdx dEdx %f",out[0]));
509 //____________________________________________________________
510 Bool_t AliTRDPIDResponse::IdentifiedAsElectron(Int_t nTracklets, const Double_t *like, Double_t p, Double_t level,Double_t centrality,ETRDPIDMethod PIDmethod) const {
512 // Check whether particle is identified as electron assuming a certain electron efficiency level
513 // Only electron and pion hypothesis is taken into account
516 // Number of tracklets
519 // Electron efficiency level
521 // If the function fails when the params are not accessible, the function returns true
523 if(!fkPIDResponseObject){
524 AliDebug(3,"No PID Param object available");
527 Double_t probEle = like[AliPID::kElectron]/(like[AliPID::kElectron] + like[AliPID::kPion]);
529 if(!fkPIDResponseObject->GetThresholdParameters(nTracklets, level, params,centrality,PIDmethod)){
530 AliError("No Params found for the given configuration");
533 Double_t threshold = 1. - params[0] - params[1] * p - params[2] * TMath::Exp(-params[3] * p);
534 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
538 //____________________________________________________________
539 Bool_t AliTRDPIDResponse::SetPIDResponseObject(const AliTRDPIDResponseObject * obj){
541 fkPIDResponseObject = obj;
542 if((AliLog::GetDebugLevel("",IsA()->GetName()))>0)fkPIDResponseObject->Print("");
547 //____________________________________________________________
548 Bool_t AliTRDPIDResponse::SetdEdxParams(const AliTRDdEdxParams * par)
550 fkTRDdEdxParams = par;