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ffb1ee30 | 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 | // 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 | |
20 | // | |
21 | // Authors: | |
22 | // Markus Fasel <M.Fasel@gsi.de> | |
23 | // Anton Andronic <A.Andronic@gsi.de> | |
24 | // | |
25 | #include <TClass.h> | |
26 | #include <TAxis.h> | |
27 | #include <TFile.h> | |
28 | #include <TH1.h> | |
29 | #include <TObjArray.h> | |
30 | #include <TString.h> | |
31 | #include <TSystem.h> | |
32 | ||
33 | #include "AliLog.h" | |
34 | ||
35 | #include "AliTRDPIDResponse.h" | |
36 | ||
37 | ClassImp(AliTRDPIDResponse) | |
38 | ||
39 | const Double_t AliTRDPIDResponse::fgkPBins[kNPBins] = {1, 2, 3, 4, 5, 6}; | |
40 | ||
41 | //____________________________________________________________ | |
42 | AliTRDPIDResponse::AliTRDPIDResponse(const Char_t * filename): | |
43 | TObject() | |
44 | ,fReferences(NULL) | |
45 | ,fPIDmethod(2) | |
46 | { | |
47 | // | |
48 | // Default constructor | |
49 | // | |
50 | memset(fMapRefHists, 0, sizeof(Int_t) * 10); | |
51 | Load(filename); | |
52 | } | |
53 | ||
54 | //____________________________________________________________ | |
55 | AliTRDPIDResponse::AliTRDPIDResponse(const AliTRDPIDResponse &ref): | |
56 | TObject(ref) | |
57 | ,fReferences(ref.fReferences) | |
58 | ,fPIDmethod(ref.fPIDmethod) | |
59 | { | |
60 | // | |
61 | // Copy constructor | |
62 | // Flat copy of the reference histos | |
63 | // For creating a deep copy call SetOwner | |
64 | // | |
65 | memcpy(fMapRefHists, ref.fMapRefHists, sizeof(Double_t) * 10); | |
66 | } | |
67 | ||
68 | //____________________________________________________________ | |
69 | AliTRDPIDResponse &AliTRDPIDResponse::operator=(const AliTRDPIDResponse &ref){ | |
70 | // | |
71 | // Assignment operator | |
72 | // Performs a flat copy of the reference histos | |
73 | // | |
74 | if(this == &ref) return *this; | |
75 | ||
76 | // Make copy | |
77 | TObject::operator=(ref); | |
78 | if(IsOwner()){ | |
79 | if(fReferences){ | |
80 | fReferences->Delete(); | |
81 | delete fReferences; | |
82 | } | |
83 | SetBit(kIsOwner, kFALSE); | |
84 | } | |
85 | fReferences = ref.fReferences; | |
86 | memcpy(fMapRefHists, ref.fMapRefHists, sizeof(Double_t) * 10); | |
87 | fPIDmethod = ref.fPIDmethod; | |
88 | ||
89 | return *this; | |
90 | } | |
91 | ||
92 | //____________________________________________________________ | |
93 | AliTRDPIDResponse::~AliTRDPIDResponse(){ | |
94 | // | |
95 | // Destructor | |
96 | // | |
97 | if(fReferences && IsOwner()){ | |
98 | fReferences->Delete(); | |
99 | delete fReferences; | |
100 | } | |
101 | } | |
102 | ||
103 | //____________________________________________________________ | |
104 | Bool_t AliTRDPIDResponse::Load(const Char_t * filename){ | |
105 | // | |
106 | // Load References into the toolkit | |
107 | // | |
108 | if(!filename) | |
109 | filename = Form("%s/STEER/LQ1dRef_v1.root",gSystem->ExpandPathName("$ALICE_ROOT")); | |
110 | TFile *in = TFile::Open(filename); | |
111 | if(!in){ | |
112 | AliError("Ref file not available."); | |
113 | return kFALSE; | |
114 | } | |
115 | ||
116 | fReferences = new TObjArray(); | |
117 | fReferences->SetOwner(); | |
118 | TIter iter(in->GetListOfKeys()); | |
119 | TObject *tmp = NULL; | |
120 | Int_t arrayPos = 0, pbin = 0; | |
121 | AliPID::EParticleType species; | |
122 | TString histname; | |
123 | while((tmp = iter())){ | |
124 | histname = tmp->GetName(); | |
125 | if(histname.BeginsWith("fHQel")){ // Electron histogram | |
126 | histname.ReplaceAll("fHQel_p",""); | |
127 | species = AliPID::kElectron; | |
128 | } else { // Pion histogram | |
129 | histname.ReplaceAll("fHQpi_p",""); | |
130 | species = AliPID::kPion; | |
131 | } | |
132 | pbin = histname.Atoi(); | |
133 | fMapRefHists[species][pbin] = arrayPos; | |
134 | fReferences->AddAt(tmp->Clone(), arrayPos); | |
135 | arrayPos++; | |
136 | } | |
137 | in->Close(); | |
138 | ||
139 | AliDebug(2, Form("Successfully loaded %d Reference Histograms", arrayPos)); | |
140 | delete in; | |
141 | return kTRUE; | |
142 | } | |
143 | ||
144 | //____________________________________________________________ | |
145 | Bool_t AliTRDPIDResponse::GetResponse(Int_t n, Double_t *dedx, Float_t *p, Double_t prob[AliPID::kSPECIES], Bool_t kNorm) | |
146 | { | |
147 | // | |
148 | // Calculate TRD likelihood values for the track based on dedx and | |
149 | // momentum values. The likelihoods are calculated by query the | |
150 | // reference data depending on the PID method selected | |
151 | // | |
152 | // Input parameter : | |
153 | // n - number of dedx slices/chamber | |
154 | // dedx - array of dedx slices organized layer wise | |
155 | // p - array of momentum measurements organized layer wise | |
156 | // | |
157 | // Return parameters | |
158 | // prob - probabilities allocated by TRD for particle specis | |
159 | // kNorm - switch to normalize probabilities to 1. By default true. If false return not normalized prob. | |
160 | // | |
161 | // Return value | |
162 | // true if calculation success | |
163 | // | |
164 | ||
165 | if(!fReferences){ | |
166 | AliWarning("Missing reference data. PID calculation not possible."); | |
167 | return kFALSE; | |
168 | } | |
169 | ||
170 | for(Int_t is(AliPID::kSPECIES); is--;) prob[is]=.2; | |
171 | Double_t prLayer[AliPID::kSPECIES]; | |
172 | memset(prLayer, 0, AliPID::kSPECIES*sizeof(Double_t)); | |
173 | Double_t DE[10], s(0.); | |
174 | for(Int_t il(kNlayer); il--;){ | |
175 | if(!CookdEdx(&dedx[il*n], &DE[0])) continue; | |
176 | ||
177 | s=0.; | |
178 | for(Int_t is(AliPID::kSPECIES); is--;){ | |
179 | prLayer[is] = GetProbabilitySingleLayer(is, p[il], DE[0]); | |
180 | s+=prLayer[is]; | |
181 | } | |
182 | if(s<1.e-30){ | |
183 | AliDebug(2, Form("Null all species prob layer[%d].", il)); | |
184 | continue; | |
185 | } | |
186 | for(Int_t is(AliPID::kSPECIES); is--;){ | |
187 | if(kNorm) prLayer[is] /= s; | |
188 | prob[is] *= prLayer[is]; | |
189 | } | |
190 | } | |
191 | if(!kNorm) return kTRUE; | |
192 | ||
193 | s=0.; | |
194 | for(Int_t is(AliPID::kSPECIES); is--;) s+=prob[is]; | |
195 | if(s<1.e-30){ | |
196 | AliDebug(2, "Null total prob."); | |
197 | return kFALSE; | |
198 | } | |
199 | for(Int_t is(AliPID::kSPECIES); is--;) prob[is]/=s; | |
200 | return kTRUE; | |
201 | } | |
202 | ||
203 | ||
204 | //____________________________________________________________ | |
205 | Double_t AliTRDPIDResponse::GetProbabilitySingleLayer(Int_t species, Double_t plocal, Double_t dEdx){ | |
206 | // | |
207 | // Get the non-normalized probability for a certain particle species as coming | |
208 | // from the reference histogram | |
209 | // Interpolation between momentum bins | |
210 | // | |
211 | Int_t pbin = GetLowerMomentumBin(plocal); | |
212 | Double_t pLayer = 0.; | |
213 | // Do Interpolation exept for underflow and overflow | |
214 | if(pbin >= 0 && pbin < kNPBins-1){ | |
215 | TH1 *refHistUpper = NULL, *refHistLower = NULL; | |
216 | refHistLower = dynamic_cast<TH1 *>(fReferences->UncheckedAt(fMapRefHists[species][pbin])); | |
217 | refHistUpper = dynamic_cast<TH1 *>(fReferences->UncheckedAt(fMapRefHists[species][pbin+1])); | |
218 | ||
219 | Double_t pLower = refHistLower->GetBinContent(refHistLower->GetXaxis()->FindBin(dEdx)); | |
220 | Double_t pUpper = refHistUpper->GetBinContent(refHistUpper->GetXaxis()->FindBin(dEdx)); | |
221 | ||
222 | pLayer = pLower + (pUpper - pLower)/(fgkPBins[pbin+1]-fgkPBins[pbin]) * plocal; | |
223 | } | |
224 | else{ | |
225 | TH1 *refHist = NULL; | |
226 | if(pbin < 0){ | |
227 | // underflow | |
228 | refHist = dynamic_cast<TH1 *>(fReferences->UncheckedAt(fMapRefHists[0][0])); | |
229 | } else { | |
230 | // overflow | |
231 | refHist = dynamic_cast<TH1 *>(fReferences->UncheckedAt(fMapRefHists[species][kNPBins])); | |
232 | } | |
233 | pLayer = refHist->GetBinContent(refHist->GetXaxis()->FindBin(dEdx)); | |
234 | } | |
235 | return pLayer; | |
236 | } | |
237 | ||
238 | //____________________________________________________________ | |
239 | Int_t AliTRDPIDResponse::GetLowerMomentumBin(Double_t p){ | |
240 | // | |
241 | // Get the momentum bin for a given momentum value | |
242 | // | |
243 | Int_t bin = -1; | |
244 | if(p > fgkPBins[kNPBins-1]) return kNPBins-1; | |
245 | for(Int_t ibin = 0; ibin < kNPBins - 1; ibin++){ | |
246 | if(p >= fgkPBins[ibin] && p < fgkPBins[ibin+1]){ | |
247 | bin = ibin; | |
248 | break; | |
249 | } | |
250 | } | |
251 | return bin; | |
252 | } | |
253 | ||
254 | //____________________________________________________________ | |
255 | void AliTRDPIDResponse::SetOwner(){ | |
256 | // | |
257 | // Make Deep Copy of the Reference Histograms | |
258 | // | |
259 | if(!fReferences || IsOwner()) return; | |
260 | TObjArray *ctmp = new TObjArray(); | |
261 | for(Int_t ien = 0; ien < fReferences->GetEntriesFast(); ien++) | |
262 | ctmp->AddAt(fReferences->UncheckedAt(ien)->Clone(), ien); | |
263 | fReferences = ctmp; | |
264 | SetBit(kIsOwner, kTRUE); | |
265 | } | |
266 | ||
267 | //____________________________________________________________ | |
268 | Bool_t AliTRDPIDResponse::CookdEdx(Double_t *in, Double_t *out) | |
269 | { | |
270 | switch(fPIDmethod){ | |
271 | case 0: // NN | |
272 | break; | |
273 | case 1: // 2D LQ | |
274 | break; | |
275 | case 2: // 1D LQ | |
276 | out[0]= 0.; | |
277 | for(Int_t islice = 0; islice < 8; islice++) out[0] += in[islice]; | |
278 | if(out[0] < 1e-6) return kFALSE; | |
279 | break; | |
280 | default: | |
281 | return kFALSE; | |
282 | } | |
283 | return kTRUE; | |
284 | } | |
285 |