1 /*************************************************************************
2 * Copyright(c) 1998-2009, 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 ///////////////////////////////////////////////////////////////////////////
17 // Dielectron SignalFunc //
21 Dielectron signal extraction class using functions as input.
23 A function to describe the signal as well as one to describe the background
24 has to be deployed by the user. Alternatively on of the default implementaions
29 ///////////////////////////////////////////////////////////////////////////
36 #include <TPaveText.h>
38 #include <TFitResult.h>
39 //#include <../hist/hist/src/TF1Helper.h> //not supposed to be used!
43 #include "AliDielectronSignalFunc.h"
45 ClassImp(AliDielectronSignalFunc)
47 AliDielectronSignalFunc::AliDielectronSignalFunc() :
48 AliDielectronSignalBase(),
58 // Default Constructor
63 //______________________________________________
64 AliDielectronSignalFunc::AliDielectronSignalFunc(const char* name, const char* title) :
65 AliDielectronSignalBase(name, title),
79 //______________________________________________
80 AliDielectronSignalFunc::~AliDielectronSignalFunc()
85 if(fFuncSignal) delete fFuncSignal;
86 if(fFuncBackground) delete fFuncBackground;
87 if(fFuncSigBack) delete fFuncSigBack;
91 //______________________________________________
92 void AliDielectronSignalFunc::Process(TObjArray * const arrhist)
95 // Fit the invariant mass histograms and retrieve the signal and background
111 AliError("Background substraction method not known!");
116 //______________________________________________
117 void AliDielectronSignalFunc::ProcessFit(TObjArray * const arrhist) {
119 // Fit the +- invariant mass distribution only
120 // Here we assume that the combined fit function is a sum of the signal and background functions
121 // and that the signal function is always the first term of this sum
124 fHistDataPM = (TH1F*)(arrhist->At(1))->Clone("histPM"); // +- SE
125 fHistDataPM->Sumw2();
127 fHistDataPM->Rebin(fRebin);
129 fHistSignal = new TH1F("HistSignal", "Like-Sign substracted signal",
130 fHistDataPM->GetXaxis()->GetNbins(),
131 fHistDataPM->GetXaxis()->GetXmin(), fHistDataPM->GetXaxis()->GetXmax());
132 fHistBackground = new TH1F("HistBackground", "Like-sign contribution",
133 fHistDataPM->GetXaxis()->GetNbins(),
134 fHistDataPM->GetXaxis()->GetXmin(), fHistDataPM->GetXaxis()->GetXmax());
136 // the starting parameters of the fit function and their limits can be tuned
137 // by the user in its macro
138 fHistDataPM->Fit(fFuncSigBack, fFitOpt.Data(), "", fFitMin, fFitMax);
139 TFitResultPtr pmFitPtr = fHistDataPM->Fit(fFuncSigBack, fFitOpt.Data(), "", fFitMin, fFitMax);
140 //TFitResult *pmFitResult = pmFitPtr.Get(); //not used when TF1Helper out
141 fFuncSignal->SetParameters(fFuncSigBack->GetParameters());
142 fFuncBackground->SetParameters(fFuncSigBack->GetParameters()+fFuncSignal->GetNpar());
144 for(Int_t iBin=1; iBin<=fHistDataPM->GetXaxis()->GetNbins(); iBin++) {
145 Double_t m = fHistDataPM->GetBinCenter(iBin);
146 Double_t pm = fHistDataPM->GetBinContent(iBin);
147 Double_t epm = fHistDataPM->GetBinError(iBin);
148 Double_t bknd = fFuncBackground->Eval(m);
150 /* to be revised ... TF1Helper
151 for(Int_t iPar=fFuncSignal->GetNpar(); iPar<fFuncSigBack->GetNpar(); iPar++) {
152 for(Int_t jPar=iPar; jPar<fFuncSigBack->GetNpar(); jPar++) {
153 TF1 gradientIpar("gradientIpar",
154 ROOT::TF1Helper::TGradientParFunction(iPar-fFuncSignal->GetNpar(),fFuncBackground),0,0,0);
155 TF1 gradientJpar("gradientJpar",
156 ROOT::TF1Helper::TGradientParFunction(jPar-fFuncSignal->GetNpar(),fFuncBackground),0,0,0);
157 ebknd += pmFitResult->CovMatrix(iPar,jPar)*
158 gradientIpar.Eval(m)*gradientJpar.Eval(m)*
159 (iPar==jPar ? 1.0 : 2.0);
163 Double_t signal = pm-bknd;
164 Double_t error = TMath::Sqrt(epm*epm+ebknd);
165 fHistSignal->SetBinContent(iBin, signal);
166 fHistSignal->SetBinError(iBin, error);
167 fHistBackground->SetBinContent(iBin, bknd);
168 fHistBackground->SetBinError(iBin, TMath::Sqrt(ebknd));
173 fValues(0) = fFuncSignal->Integral(fIntMin, fIntMax)/fHistDataPM->GetBinWidth(1);
175 /* to be revised ... TF1Helper
176 for(Int_t iPar=0; iPar<fFuncSignal->GetNpar(); iPar++) {
177 for(Int_t jPar=iPar; jPar<fFuncSignal->GetNpar(); jPar++) {
178 TF1 gradientIpar("gradientIpar",
179 ROOT::TF1Helper::TGradientParFunction(iPar,fFuncSignal),0,0,0);
180 TF1 gradientJpar("gradientJpar",
181 ROOT::TF1Helper::TGradientParFunction(jPar,fFuncSignal),0,0,0);
182 fErrors(0) += pmFitResult->CovMatrix(iPar,jPar)*
183 gradientIpar.Integral(fIntMin,fIntMax)*gradientJpar.Integral(fIntMin,fIntMax)*
184 (iPar==jPar ? 1.0 : 2.0);
189 fValues(1) = fFuncBackground->Integral(fIntMin, fIntMax)/fHistDataPM->GetBinWidth(1);
191 /* to be revised... TF1Helper
192 for(Int_t iPar=fFuncSignal->GetNpar(); iPar<fFuncSigBack->GetNpar(); iPar++) {
193 for(Int_t jPar=iPar; jPar<fFuncSigBack->GetNpar(); jPar++) {
194 TF1 gradientIpar("gradientIpar",
195 ROOT::TF1Helper::TGradientParFunction(iPar-fFuncSignal->GetNpar(),fFuncBackground),0,0,0);
196 TF1 gradientJpar("gradientJpar",
197 ROOT::TF1Helper::TGradientParFunction(jPar-fFuncSignal->GetNpar(),fFuncBackground),0,0,0);
198 fErrors(1) += pmFitResult->CovMatrix(iPar,jPar)*
199 gradientIpar.Integral(fIntMin, fIntMax)*gradientJpar.Integral(fIntMin, fIntMax)*
200 (iPar==jPar ? 1.0 : 2.0);
207 fValues(0) = fHistSignal->IntegralAndError(fHistSignal->FindBin(fIntMin),
208 fHistSignal->FindBin(fIntMax), fErrors(0));
210 fValues(1) = fHistBackground->IntegralAndError(fHistBackground->FindBin(fIntMin),
211 fHistBackground->FindBin(fIntMax),
214 // S/B and significance
215 SetSignificanceAndSOB();
216 fValues(4) = fFuncSigBack->GetParameter(fParMass);
217 fErrors(4) = fFuncSigBack->GetParError(fParMass);
218 fValues(5) = fFuncSigBack->GetParameter(fParMassWidth);
219 fErrors(5) = fFuncSigBack->GetParError(fParMassWidth);
224 //______________________________________________
225 void AliDielectronSignalFunc::ProcessLS(TObjArray * const arrhist) {
227 // Substract background using the like-sign spectrum
229 fHistDataPP = (TH1F*)(arrhist->At(0))->Clone("histPP"); // ++ SE
230 fHistDataPM = (TH1F*)(arrhist->At(1))->Clone("histPM"); // +- SE
231 fHistDataMM = (TH1F*)(arrhist->At(2))->Clone("histMM"); // -- SE
233 fHistDataPP->Rebin(fRebin);
234 fHistDataPM->Rebin(fRebin);
235 fHistDataMM->Rebin(fRebin);
237 fHistDataPP->Sumw2();
238 fHistDataPM->Sumw2();
239 fHistDataMM->Sumw2();
241 fHistSignal = new TH1F("HistSignal", "Like-Sign substracted signal",
242 fHistDataPM->GetXaxis()->GetNbins(),
243 fHistDataPM->GetXaxis()->GetXmin(), fHistDataPM->GetXaxis()->GetXmax());
244 fHistBackground = new TH1F("HistBackground", "Like-sign contribution",
245 fHistDataPM->GetXaxis()->GetNbins(),
246 fHistDataPM->GetXaxis()->GetXmin(), fHistDataPM->GetXaxis()->GetXmax());
248 // fit the +- mass distribution
249 fHistDataPM->Fit(fFuncSigBack, fFitOpt.Data(), "", fFitMin, fFitMax);
250 fHistDataPM->Fit(fFuncSigBack, fFitOpt.Data(), "", fFitMin, fFitMax);
251 // declare the variables where the like-sign fit results will be stored
252 TFitResult *ppFitResult = 0x0;
253 TFitResult *mmFitResult = 0x0;
254 // fit the like sign background
255 TF1 *funcClonePP = (TF1*)fFuncBackground->Clone("funcClonePP");
256 TF1 *funcCloneMM = (TF1*)fFuncBackground->Clone("funcCloneMM");
257 fHistDataPP->Fit(funcClonePP, fFitOpt.Data(), "", fFitMin, fFitMax);
258 TFitResultPtr ppFitPtr = fHistDataPP->Fit(funcClonePP, fFitOpt.Data(), "", fFitMin, fFitMax);
259 ppFitResult = ppFitPtr.Get();
260 fHistDataMM->Fit(funcCloneMM, fFitOpt.Data(), "", fFitMin, fFitMax);
261 TFitResultPtr mmFitPtr = fHistDataMM->Fit(funcCloneMM, fFitOpt.Data(), "", fFitMin, fFitMax);
262 mmFitResult = mmFitPtr.Get();
264 /* to be revised ... TF1Helper
265 for(Int_t iBin=1; iBin<=fHistDataPM->GetXaxis()->GetNbins(); iBin++) {
266 Double_t m = fHistDataPM->GetBinCenter(iBin);
267 Double_t pm = fHistDataPM->GetBinContent(iBin);
268 Double_t pp = funcClonePP->Eval(m);
269 Double_t mm = funcCloneMM->Eval(m);
270 Double_t epm = fHistDataPM->GetBinError(iBin);
272 for(Int_t iPar=0; iPar<funcClonePP->GetNpar(); iPar++) {
273 for(Int_t jPar=iPar; jPar<funcClonePP->GetNpar(); jPar++) {
274 TF1 gradientIpar("gradientIpar",
275 ROOT::TF1Helper::TGradientParFunction(iPar,funcClonePP),0,0,0);
276 TF1 gradientJpar("gradientJpar",
277 ROOT::TF1Helper::TGradientParFunction(jPar,funcClonePP),0,0,0);
278 epp += ppFitResult->CovMatrix(iPar,jPar)*
279 gradientIpar.Eval(m)*gradientJpar.Eval(m)*
280 (iPar==jPar ? 1.0 : 2.0);
285 for(Int_t iPar=0; iPar<funcCloneMM->GetNpar(); iPar++) {
286 for(Int_t jPar=iPar; jPar<funcCloneMM->GetNpar(); jPar++) {
287 TF1 gradientIpar("gradientIpar",
288 ROOT::TF1Helper::TGradientParFunction(iPar,funcCloneMM),0,0,0);
289 TF1 gradientJpar("gradientJpar",
290 ROOT::TF1Helper::TGradientParFunction(jPar,funcCloneMM),0,0,0);
291 emm += mmFitResult->CovMatrix(iPar,jPar)*
292 gradientIpar.Eval(m)*gradientJpar.Eval(m)*
293 (iPar==jPar ? 1.0 : 2.0);
297 Double_t signal = pm-2.0*TMath::Sqrt(pp*mm);
298 Double_t background = 2.0*TMath::Sqrt(pp*mm);
299 // error propagation on the signal calculation above
300 Double_t esignal = TMath::Sqrt(epm*epm+(mm/pp)*epp+(pp/mm)*emm);
301 Double_t ebackground = TMath::Sqrt((mm/pp)*epp+(pp/mm)*emm);
302 fHistSignal->SetBinContent(iBin, signal);
303 fHistSignal->SetBinError(iBin, esignal);
304 fHistBackground->SetBinContent(iBin, background);
305 fHistBackground->SetBinError(iBin, ebackground);
310 fValues(0) = fHistSignal->IntegralAndError(fHistSignal->FindBin(fIntMin),
311 fHistSignal->FindBin(fIntMax), fErrors(0));
313 fValues(1) = fHistBackground->IntegralAndError(fHistBackground->FindBin(fIntMin),
314 fHistBackground->FindBin(fIntMax),
316 // S/B and significance
317 SetSignificanceAndSOB();
318 fValues(4) = fFuncSigBack->GetParameter(fParMass);
319 fErrors(4) = fFuncSigBack->GetParError(fParMass);
320 fValues(5) = fFuncSigBack->GetParameter(fParMassWidth);
321 fErrors(5) = fFuncSigBack->GetParError(fParMassWidth);
326 //______________________________________________
327 void AliDielectronSignalFunc::ProcessEM(TObjArray * const arrhist) {
329 // Substract background with the event mixing technique
331 arrhist->GetEntries(); // just to avoid the unused parameter warning
332 AliError("Event mixing for background substraction method not implemented!");
335 //______________________________________________
336 void AliDielectronSignalFunc::SetFunctions(TF1 * const combined, TF1 * const sig, TF1 * const back,
337 Int_t parM, Int_t parMres)
340 // Set the signal, background functions and combined fit function
341 // Note: The process method assumes that the first n parameters in the
342 // combined fit function correspond to the n parameters of the signal function
343 // and the n+1 to n+m parameters to the m parameters of the background function!!!
345 if (!sig||!back||!combined) {
346 AliError("Both, signal and background function need to be set!");
350 fFuncBackground=back;
351 fFuncSigBack=combined;
353 fParMassWidth=parMres;
356 //______________________________________________
357 void AliDielectronSignalFunc::SetDefaults(Int_t type)
360 // Setup some default functions:
361 // type = 0: gaus signal + linear background in 2.5 - 4 GeV inv. mass
362 // type = 1: gaus signal + exponential background in 2.5 - 4 GeV inv. mass
363 // type = 2: half gaussian, half exponential signal function
364 // type = 3: Crystal-Ball function
365 // type = 4: Crystal-Ball signal + exponential background
369 fFuncSignal=new TF1("DieleSignal","gaus",2.5,4);
370 fFuncBackground=new TF1("DieleBackground","pol1",2.5,4);
371 fFuncSigBack=new TF1("DieleCombined","gaus+pol1(3)",2.5,4);
373 fFuncSigBack->SetParameters(1,3.1,.05,2.5,1);
374 fFuncSigBack->SetParLimits(0,0,10000000);
375 fFuncSigBack->SetParLimits(1,3.05,3.15);
376 fFuncSigBack->SetParLimits(2,.02,.1);
379 fFuncSignal=new TF1("DieleSignal","gaus",2.5,4);
380 fFuncBackground=new TF1("DieleBackground","[0]*exp(-(x-[1])/[2])",2.5,4);
381 fFuncSigBack=new TF1("DieleCombined","gaus+[3]*exp(-(x-[4])/[5])",2.5,4);
383 fFuncSigBack->SetParameters(1,3.1,.05,1,2.5,1);
384 fFuncSigBack->SetParLimits(0,0,10000000);
385 fFuncSigBack->SetParLimits(1,3.05,3.15);
386 fFuncSigBack->SetParLimits(2,.02,.1);
389 // half gaussian, half exponential signal function
390 // exponential background
391 fFuncSignal = new TF1("DieleSignal","(x<[1])*([0]*(exp(-0.5*((x-[1])/[2])^2)+exp((x-[1])/[3])*(1-exp(-0.5*((x-[1])/[2])^2))))+(x>=[1])*([0]*exp(-0.5*((x-[1])/[2])^2))",2.5,4);
392 fFuncBackground = new TF1("DieleBackground","[0]*exp(-(x-[1])/[2])+[3]",2.5,4);
393 fFuncSigBack = new TF1("DieleCombined","(x<[1])*([0]*(exp(-0.5*((x-[1])/[2])^2)+exp((x-[1])/[3])*(1-exp(-0.5*((x-[1])/[2])^2))))+(x>=[1])*([0]*exp(-0.5*((x-[1])/[2])^2))+[4]*exp(-(x-[5])/[6])+[7]",2.5,4);
394 fFuncSigBack->SetParameters(1.,3.1,.05,.1,1,2.5,1,0);
396 fFuncSigBack->SetParLimits(0,0,10000000);
397 fFuncSigBack->SetParLimits(1,3.05,3.15);
398 fFuncSigBack->SetParLimits(2,.02,.1);
399 fFuncSigBack->FixParameter(6,2.5);
400 fFuncSigBack->FixParameter(7,0);
405 //______________________________________________
406 void AliDielectronSignalFunc::Draw(const Option_t* option)
409 // Draw the fitted function
412 TString drawOpt(option);
415 Bool_t optStat=drawOpt.Contains("stat");
417 fFuncSigBack->SetNpx(200);
418 fFuncSigBack->SetRange(fIntMin,fIntMax);
419 fFuncBackground->SetNpx(200);
420 fFuncBackground->SetRange(fIntMin,fIntMax);
422 TGraph *grSig=new TGraph(fFuncSigBack);
423 grSig->SetFillColor(kGreen);
424 grSig->SetFillStyle(3001);
426 TGraph *grBack=new TGraph(fFuncBackground);
427 grBack->SetFillColor(kRed);
428 grBack->SetFillStyle(3001);
430 grSig->SetPoint(0,grBack->GetX()[0],grBack->GetY()[0]);
431 grSig->SetPoint(grSig->GetN()-1,grBack->GetX()[grBack->GetN()-1],grBack->GetY()[grBack->GetN()-1]);
433 grBack->SetPoint(0,grBack->GetX()[0],0.);
434 grBack->SetPoint(grBack->GetN()-1,grBack->GetX()[grBack->GetN()-1],0.);
436 fFuncSigBack->SetRange(fFitMin,fFitMax);
437 fFuncBackground->SetRange(fFitMin,fFitMax);
439 if (!drawOpt.Contains("same")){
449 if(fMethod==kFitted) grBack->Draw("f");
450 fFuncSigBack->Draw("same");
451 fFuncSigBack->SetLineWidth(2);
452 if(fMethod==kLikeSign) {
453 fHistDataPP->SetLineWidth(2);
454 fHistDataPP->SetLineColor(6);
455 fHistDataPP->Draw("same");
456 fHistDataMM->SetLineWidth(2);
457 fHistDataMM->SetLineColor(8);
458 fHistDataMM->Draw("same");
462 fFuncBackground->Draw("same");
464 if (optStat) DrawStats();