// Standard demo of the Profile Likelihood calculcator /* StandardProfileLikelihoodDemo Author: Kyle Cranmer date: Dec. 2010 This is a standard demo that can be used with any ROOT file prepared in the standard way. You specify: - name for input ROOT file - name of workspace inside ROOT file that holds model and data - name of ModelConfig that specifies details for calculator tools - name of dataset With default parameters the macro will attempt to run the standard hist2workspace example and read the ROOT file that it produces. The actual heart of the demo is only about 10 lines long. The ProfileLikelihoodCalculator is based on Wilks's theorem and the asymptotic properties of the profile likeihood ratio (eg. that it is chi-square distributed for the true value). */ #include "TFile.h" #include "TROOT.h" #include "RooWorkspace.h" #include "RooAbsData.h" #include "RooRealVar.h" #include "RooStats/ModelConfig.h" #include "RooStats/ProfileLikelihoodCalculator.h" #include "RooStats/LikelihoodInterval.h" #include "RooStats/LikelihoodIntervalPlot.h" using namespace RooFit; using namespace RooStats; void StandardProfileLikelihoodDemo(const char* infile = "", const char* workspaceName = "combined", const char* modelConfigName = "ModelConfig", const char* dataName = "obsData"){ ///////////////////////////////////////////////////////////// // First part is just to access a user-defined file // or create the standard example file if it doesn't exist //////////////////////////////////////////////////////////// const char* filename = ""; if (!strcmp(infile,"")) filename = "results/example_combined_GaussExample_model.root"; else filename = infile; // Check if example input file exists TFile *file = TFile::Open(filename); // if input file was specified byt not found, quit if(!file && strcmp(infile,"")){ cout <<"file not found" << endl; return; } // if default file not found, try to create it if(!file ){ // Normally this would be run on the command line cout <<"will run standard hist2workspace example"<<endl; gROOT->ProcessLine(".! prepareHistFactory ."); gROOT->ProcessLine(".! hist2workspace config/example.xml"); cout <<"\n\n---------------------"<<endl; cout <<"Done creating example input"<<endl; cout <<"---------------------\n\n"<<endl; } // now try to access the file again file = TFile::Open(filename); if(!file){ // if it is still not there, then we can't continue cout << "Not able to run hist2workspace to create example input" <<endl; return; } ///////////////////////////////////////////////////////////// // Tutorial starts here //////////////////////////////////////////////////////////// // get the workspace out of the file RooWorkspace* w = (RooWorkspace*) file->Get(workspaceName); if(!w){ cout <<"workspace not found" << endl; return; } // get the modelConfig out of the file ModelConfig* mc = (ModelConfig*) w->obj(modelConfigName); // get the modelConfig out of the file RooAbsData* data = w->data(dataName); // make sure ingredients are found if(!data || !mc){ w->Print(); cout << "data or ModelConfig was not found" <<endl; return; } ///////////////////////////////////////////// // create and use the ProfileLikelihoodCalculator // to find and plot the 95% confidence interval // on the parameter of interest as specified // in the model config ProfileLikelihoodCalculator pl(*data,*mc); pl.SetConfidenceLevel(0.95); // 95% interval LikelihoodInterval* interval = pl.GetInterval(); // print out the iterval on the first Parameter of Interest RooRealVar* firstPOI = (RooRealVar*) mc->GetParametersOfInterest()->first(); cout << "\n95% interval on " <<firstPOI->GetName()<<" is : ["<< interval->LowerLimit(*firstPOI) << ", "<< interval->UpperLimit(*firstPOI) <<"] "<<endl; // make a plot cout << "making a plot of the profile likelihood function ....(if it is taking a lot of time use less points or the TF1 drawing option)\n"; LikelihoodIntervalPlot plot(interval); plot.SetNPoints(50); // do not use too many points, it could become very slow for some models plot.Draw(""); // use option TF1 if too slow (plot.Draw("tf1") }