4 // General implementation of a single cut strategy, which can be:
5 // - a value contained in a given interval [--> IsBetween() ]
6 // - a value equal to a given reference [--> MatchesValue()]
8 // In all cases, the reference value(s) is (are) given as data members
9 // and each kind of cut requires a given value type (Int, UInt, Double),
10 // but the cut check procedure is then automatized and chosen thanks to
11 // an enumeration of the implemented cut types.
12 // At the end, the user (or any other point which uses this object) has
13 // to use the method IsSelected() to check if this cut has been passed.
15 // authors: Martin Vala (martin.vala@cern.ch)
16 // Alberto Pulvirenti (alberto.pulvirenti@ct.infn.it)
20 #include "AliExternalTrackParam.h"
22 #include "AliRsnDaughter.h"
23 #include "AliRsnCutPID.h"
25 ClassImp(AliRsnCutPID)
27 //_________________________________________________________________________________________________
28 AliRsnCutPID::AliRsnCutPID() :
34 // Default constructor.
35 // Sets the cut to realistic PID with default weights,
36 // and defines the 'fMinI' value of the base class as the PID
37 // to which we want to compare this object.
42 for (i = 0; i < kDetectors; i++) {
43 fUseDetector[i] = kFALSE;
44 fPtThreshold[i] = 0.0;
45 fGoAboveThreshold[i] = kTRUE;
48 for (i = 0; i < AliPID::kSPECIES; i++) {
53 SetTargetType(AliRsnTarget::kDaughter);
56 //_________________________________________________________________________________________________
57 AliRsnCutPID::AliRsnCutPID(const char *name, AliPID::EParticleType pid, Double_t probMin, Bool_t perfectPID) :
58 AliRsnCut(name, AliRsnCut::kDaughter, (Int_t)pid),
63 // Default constructor.
64 // Sets the cut to realistic PID with default weights,
65 // and defines the 'fMinI' value of the base class as the PID
66 // to which we want to compare this object.
71 for (i = 0; i < kDetectors; i++) {
72 fUseDetector[i] = kFALSE;
73 fPtThreshold[i] = 0.0;
74 fGoAboveThreshold[i] = kTRUE;
77 for (i = 0; i < AliPID::kSPECIES; i++) {
85 SetTargetType(AliRsnTarget::kDaughter);
88 //_____________________________________________________________________________
89 Bool_t AliRsnCutPID::CheckThreshold(EDetector det, Double_t value)
92 // Checks if the passed value (track pT) stays in the
93 // interval where the detector should be accepted
96 if (!CheckBounds(det)) return kFALSE;
98 if (fGoAboveThreshold[det]) return (value >= fPtThreshold[det]);
99 else return (value <= fPtThreshold[det]);
102 //_________________________________________________________________________________________________
103 Bool_t AliRsnCutPID::ComputeWeights(AliRsnDaughter *daughter)
106 // Compute the PID weights using the class settings.
107 // If the argument is an ESD track, customized weights can be computed
108 // It the argument is a track (ESD or AOD), at least default weights
109 // can be computed, otherwise, no weights can be defined.
110 // The return value tells if the operation was successful.
114 Bool_t useDefault = fUseDefault;
115 Bool_t perfectPID = fPerfect;
116 if (perfectPID && !daughter->GetRefMC()) return kFALSE;
117 if (!daughter->Ref2ESDtrack()) useDefault = kTRUE;
118 if (!daughter->Ref2ESDtrack() && !daughter->Ref2AODtrack()) return kFALSE;
120 // if perfect PID ise required,
121 // compare the PDG code of the type stored in 'fMinI' of the cut
122 // and that of the particle which is checked, looking at its MC
124 i = TMath::Abs(AliPID::ParticleCode(fMinI));
125 j = daughter->GetPDG();
129 // if default weights are (or need to be) used,
130 // they are taken directly and function exits
132 if (daughter->Ref2ESDtrack())
133 daughter->Ref2ESDtrack()->GetESDpid(fWeight);
135 for (i = 0; i < AliPID::kSPECIES; i++)
136 fWeight[i] = daughter->Ref2AODtrack()->PID()[i];
141 // if we arrive here, this means that we have an ESD track
142 // and we want to customize the PID
143 AliESDtrack *track = daughter->Ref2ESDtrack();
144 Double_t w[kDetectors][AliPID::kSPECIES];
145 track->GetITSpid(w[kITS]);
146 track->GetTPCpid(w[kTPC]);
147 track->GetTRDpid(w[kTRD]);
148 track->GetTOFpid(w[kTOF]);
149 track->GetHMPIDpid(w[kHMPID]);
151 // if a detector is excluded or the track has not the right pT
152 // all related weights are set to 1 in order not to contribute
153 // to final multiplication
154 for (i = 0; i < kDetectors; i++) {
155 if (!fUseDetector[i] || !CheckThreshold((EDetector)i, track->Pt())) {
156 for (j = 0; j < AliPID::kSPECIES; j++) {
162 // multiplicate all weights to compute final one
163 for (i = 0; i < AliPID::kSPECIES; i++) {
164 fWeight[i] = w[kITS][i] * w[kTPC][i] * w[kTRD][i] * w[kTOF][i] * w[kHMPID][i];
170 //_________________________________________________________________________________________________
171 Int_t AliRsnCutPID::RealisticPID(AliRsnDaughter * const daughter, Double_t &prob)
174 // Combines the weights collected from chosen detectors with the priors
175 // and gives the corresponding particle with the largest probability,
176 // in terms of the AliPID particle type enumeration.
177 // The argument, passed by reference, gives the corresponding probability,
178 // since the cut could require that it is larger than a threshold.
181 // try to compute the weights
182 if (!ComputeWeights(daughter)) {
184 return AliPID::kUnknown;
187 // combine with priors and normalize
189 Double_t sum = 0.0, w[AliPID::kSPECIES];
190 for (i = 0; i < AliPID::kSPECIES; i++) {
191 w[i] = fWeight[i] * fPrior[i];
197 return AliPID::kUnknown;
199 for (i = 0; i < AliPID::kSPECIES; i++) w[i] /= sum;
201 // find the largest probability and related PID
204 for (i = 1; i < AliPID::kSPECIES; i++) {
211 // return the value, while the probability
212 // will be consequentially set
216 //_________________________________________________________________________________________________
217 Int_t AliRsnCutPID::PerfectPID(AliRsnDaughter * const daughter)
220 // If MC is present, retrieve the particle corresponding to the used track
221 // (using the fRefMC data member) and then return the true particle type
222 // taken from the PDG code of the reference particle itself, converted
223 // into the enumeration from AliPID object.
226 // works only if the MC is present
227 if (!daughter->GetRefMC()) return AliPID::kUnknown;
229 // get the PDG code of the particle
230 Int_t pdg = daughter->GetPDG();
232 // loop over all species listed in AliPID to find the match
234 for (i = 0; i < AliPID::kSPECIES; i++) {
235 if (AliPID::ParticleCode(i) == pdg) return i;
238 return AliPID::kUnknown;
241 //_________________________________________________________________________________________________
242 Bool_t AliRsnCutPID::IsSelected(TObject *object)
248 // convert the object into the unique correct type
250 if (!TargetOK(object)) {
251 AliError(Form("[%s]: this cut works only with AliRsnDaughter objects", GetName()));
255 // if target is OK, do a dynamic cast
256 AliRsnDaughter *daughter = fDaughter;
258 // depending on the PID type, recalls the appropriate method:
259 // in case of perfect PID, checks only if the PID type is
260 // corresponding to the request in the cut (fMinI)
261 // while in case of realistic PID checks also the probability
262 // to be within the required interval
263 if (fPerfect && daughter) {
264 fCutValueI = PerfectPID(daughter);
266 } else if (daughter) {
267 fCutValueI = RealisticPID(daughter, fCutValueD);
268 return OkValueI() && OkRangeD();
273 //__________________________________________________________________________________________________
274 void AliRsnCutPID::IncludeDetector(EDetector det, Double_t threshold, Bool_t goAbove)
277 // Include a detector for a customized weight computing
278 // and specify also its eventual threshold and if the detector
279 // must be used above or below the threshold.
280 // By default the threshold is zero and detector is always used.
283 if (!CheckBounds(det)) return;
285 fUseDetector[det] = kTRUE;
286 fPtThreshold[det] = threshold;
287 fGoAboveThreshold[det] = goAbove;