TrackAssociator/test/resolution_fit.cxx

0001 #include "RooPlot.h"
0002 #include "RooRealVar.h"
0003 #include "RooGaussian.h"
0004 #include "RooDataHist.h"
0005 #include "RooAddPdf.h"
0006 #include "RooGlobalFunc.h"
0007 #include "CruijffPdf.h"
0008 #include "TH1F.h"
0009 // best for fits with a core gaussian and some outliers
0010 RooPlot* double_gauss_fit(TH1* histo, TString title = "",
0011               double min_mean1=-100, double max_mean1=100,
0012               double min_mean2=-100, double max_mean2=100,
0013               double min_sigma1=0.001, double max_sigma1=10,
0014               double min_sigma2=1, double max_sigma2=10)
0015 {
0016    using namespace RooFit;
0017    RooRealVar x("x","x",0);
0018    RooRealVar mean1("mean1","mean1",min_mean1,max_mean1);
0019    RooRealVar mean2("mean2","mean2",min_mean2,max_mean2);
0020    RooRealVar sigma1("sigma1","sigma1",min_sigma1,max_sigma1);
0021    RooRealVar sigma2("sigma2","sigma2",min_sigma2,max_sigma2);
0022    RooGaussian pdf1("gaus1","gaus1",x,mean1,sigma1);
0023    RooGaussian pdf2("gaus2","gaus2",x,mean2,sigma2);
0024    RooRealVar frac("frac","frac",0,1);
0025    RooAddPdf pdf("pdf","pdf",pdf1,pdf2,frac);
0026    RooDataHist data("data","data",x,histo);
0027    pdf.fitTo(data,RooFit::Minos(kFALSE));
0028    RooPlot* frame = x.frame();
0029    data.plotOn(frame);
0030    data.statOn(frame,What("N"));
0031    pdf.paramOn(frame,Format("NEA",AutoPrecision(2)));
0032    pdf.plotOn(frame);
0033    frame->SetTitle(title);
0034    frame->Draw();
0035    return frame;
0036 }
0037
0038 // best for asymmetrical distributions with long tails
0039 RooPlot* cruijff_fit(TH1* histo, TString title = "",
0040              double min_mean=0, double max_mean=10,
0041              double min_sigmaL=0.001, double max_sigmaL=10,
0042              double min_sigmaR=0.001, double max_sigmaR=10)
0043 {
0044    using namespace RooFit;
0045    RooRealVar x("x","x",0);
0046    RooRealVar mean("mean","mean",min_mean,max_mean);
0047    RooRealVar sigmaL("sigmaL","sigmaL",min_sigmaL,max_sigmaL);
0048    RooRealVar sigmaR("sigmaR","sigmaR",min_sigmaR,max_sigmaR);
0049    RooRealVar alphaL("alphaL","alphaL",0,1);
0050    RooRealVar alphaR("alphaR","alphaR",0,1);
0051    CruijffPdf pdf("pdf","pdf",x,mean,sigmaL,sigmaR,alphaL,alphaR);
0052    RooDataHist data("data","data",x,histo);
0053    pdf.fitTo(data,RooFit::Minos(kFALSE));
0054    RooPlot* frame = x.frame();
0055    data.plotOn(frame);
0056    data.statOn(frame,What("N"));
0057    pdf.paramOn(frame,Format("NEA",AutoPrecision(2)));
0058    pdf.plotOn(frame);
0059    frame->SetTitle(title);
0060    frame->Draw();
0061    return frame;
0062 }
0063