rf509_wsinteractive.C

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/// \file
/// \ingroup tutorial_roofit
/// \notebook -js
///  'ORGANIZATION AND SIMULTANEOUS FITS' RooFit tutorial macro #509
///
///   Easy CINT interactive access to workspace contents through a
///   'C++' namespace in CINT that maps the workspace contents in a typesafe way
///
///   *********************************************************************************
///   *** NB: This macro exploits a feature native to CINT and _cannot_ be compiled ***
///   *********************************************************************************
///
/// \macro_image
/// \macro_output
/// \macro_code
/// \author 04/2009 - Wouter Verkerke


#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooChebychev.h"
#include "RooAddPdf.h"
#include "RooWorkspace.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TFile.h"
#include "TH1.h"
using namespace RooFit ;


void fillWorkspace(RooWorkspace& w) ;

void rf509_wsinteractive()
{
   // C r e a t e  a n d   f i l l   w o r k s p a c e
   // ------------------------------------------------

   // Create a workspace named 'w'
   // With CINT w could exports its contents to
   // a same-name C++ namespace in CINT 'namespace w'.
   // but this does not work anymore in CLING.
   // so this tutorial is an example on how to
   // change the code
   RooWorkspace* w1 = new RooWorkspace("w",kTRUE) ;

   // Fill workspace with p.d.f. and data in a separate function
   fillWorkspace(*w1) ;

   // Print workspace contents
   w1->Print() ;

   // this does not work anymore with CLING
   // use normal workspace functionality


   // U s e   w o r k s p a c e   c o n t e n t s
   // ----------------------------------------------


   // Old syntax to use the name space prefix operator to access the workspace contents
   //
   //RooDataSet* d = w::model.generate(w::x,1000) ;
   //RooFitResult* r = w::model.fitTo(*d) ;

   // use normal workspace methods
   RooAbsPdf * model = w1->pdf("model");
   RooRealVar * x = w1->var("x");

   RooDataSet* d = model->generate(*x,1000) ;
   RooFitResult* r = model->fitTo(*d) ;

   // old syntax to access the variable x
   // RooPlot* frame = w::x.frame() ;

   RooPlot* frame = x->frame() ;
   d->plotOn(frame) ;

   // OLD syntax to omit x::
   // NB: The 'w::' prefix can be omitted if namespace w is imported in local namespace
   // in the usual C++ way
   //
   // using namespace w;
   // model.plotOn(frame) ;
   // model.plotOn(frame,Components(bkg),LineStyle(kDashed)) ;

   // new correct syntax
   RooAbsPdf *bkg = w1->pdf("bkg");
   model->plotOn(frame);
   model->plotOn(frame,Components(*bkg),LineStyle(kDashed)) ;

   // Draw the frame on the canvas
   new TCanvas("rf509_wsinteractive","rf509_wsinteractive",600,600) ;
   gPad->SetLeftMargin(0.15) ; frame->GetYaxis()->SetTitleOffset(1.4) ; frame->Draw() ;


}




void fillWorkspace(RooWorkspace& w)
{
   // C r e a t e  p d f   a n d   f i l l   w o r k s p a c e
   // --------------------------------------------------------

   // Declare observable x
   RooRealVar x("x","x",0,10) ;

   // Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters
   RooRealVar mean("mean","mean of gaussians",5,0,10) ;
   RooRealVar sigma1("sigma1","width of gaussians",0.5) ;
   RooRealVar sigma2("sigma2","width of gaussians",1) ;

   RooGaussian sig1("sig1","Signal component 1",x,mean,sigma1) ;
   RooGaussian sig2("sig2","Signal component 2",x,mean,sigma2) ;

   // Build Chebychev polynomial p.d.f.
   RooRealVar a0("a0","a0",0.5,0.,1.) ;
   RooRealVar a1("a1","a1",0.2,0.,1.) ;
   RooChebychev bkg("bkg","Background",x,RooArgSet(a0,a1)) ;

   // Sum the signal components into a composite signal p.d.f.
   RooRealVar sig1frac("sig1frac","fraction of component 1 in signal",0.8,0.,1.) ;
   RooAddPdf sig("sig","Signal",RooArgList(sig1,sig2),sig1frac) ;

   // Sum the composite signal and background
   RooRealVar bkgfrac("bkgfrac","fraction of background",0.5,0.,1.) ;
   RooAddPdf  model("model","g1+g2+a",RooArgList(bkg,sig),bkgfrac) ;

   w.import(model) ;

}