rf405_realtocatfuncs.C

Go to the documentation of this file.

/// \file
/// \ingroup tutorial_roofit
/// \notebook -js
/// Data and categories: demonstration of real-->discrete mapping functions
///
/// \macro_image
/// \macro_output
/// \macro_code
/// \author 07/2008 - Wouter Verkerke

#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooCategory.h"
#include "RooThresholdCategory.h"
#include "RooBinningCategory.h"
#include "Roo1DTable.h"
#include "RooArgusBG.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
using namespace RooFit;

void rf405_realtocatfuncs()
{

   // D e f i n e   p d f   i n   x ,   s a m p l e   d a t a s e t   i n   x
   // ------------------------------------------------------------------------

   // Define a dummy PDF in x
   RooRealVar x("x", "x", 0, 10);
   RooArgusBG a("a", "argus(x)", x, RooConst(10), RooConst(-1));

   // Generate a dummy dataset
   RooDataSet *data = a.generate(x, 10000);

   // C r e a t e   a   t h r e s h o l d   r e a l - > c a t   f u n c t i o n
   // --------------------------------------------------------------------------

   // A RooThresholdCategory is a category function that maps regions in a real-valued
   // input observable observables to state names. At construction time a 'default'
   // state name must be specified to which all values of x are mapped that are not
   // otherwise assigned
   RooThresholdCategory xRegion("xRegion", "region of x", x, "Background");

   // Specify thresholds and state assignments one-by-one.
   // Each statement specifies that all values _below_ the given value
   // (and above any lower specified threshold) are mapped to the
   // category state with the given name
   //
   // Background | SideBand | Signal | SideBand | Background
   //           4.23       5.23     8.23       9.23
   xRegion.addThreshold(4.23, "Background");
   xRegion.addThreshold(5.23, "SideBand");
   xRegion.addThreshold(8.23, "Signal");
   xRegion.addThreshold(9.23, "SideBand");

   // U s e   t h r e s h o l d   f u n c t i o n   t o   p l o t   d a t a   r e g i o n s
   // -------------------------------------------------------------------------------------

   // Add values of threshold function to dataset so that it can be used as observable
   data->addColumn(xRegion);

   // Make plot of data in x
   RooPlot *xframe = x.frame(Title("Demo of threshold and binning mapping functions"));
   data->plotOn(xframe);

   // Use calculated category to select sideband data
   data->plotOn(xframe, Cut("xRegion==xRegion::SideBand"), MarkerColor(kRed), LineColor(kRed));

   // C r e a t e   a   b i n n i n g    r e a l - > c a t   f u n c t i o n
   // ----------------------------------------------------------------------

   // A RooBinningCategory is a category function that maps bins of a (named) binning definition
   // in a real-valued input observable observables to state names. The state names are automatically
   // constructed from the variable name, the binning name and the bin number. If no binning name
   // is specified the default binning is mapped

   x.setBins(10, "coarse");
   RooBinningCategory xBins("xBins", "coarse bins in x", x, "coarse");

   // U s e   b i n n i n g   f u n c t i o n   f o r   t a b u l a t i o n   a n d   p l o t t i n g
   // -----------------------------------------------------------------------------------------------

   // Print table of xBins state multiplicity. Note that xBins does not need to be an observable in data
   // it can be a function of observables in data as well
   Roo1DTable *xbtable = data->table(xBins);
   xbtable->Print("v");

   // Add values of xBins function to dataset so that it can be used as observable
   RooCategory *xb = (RooCategory *)data->addColumn(xBins);

   // Define range "alt" as including bins 1,3,5,7,9
   xb->setRange("alt", "x_coarse_bin1,x_coarse_bin3,x_coarse_bin5,x_coarse_bin7,x_coarse_bin9");

   // Construct subset of data matching range "alt" but only for the first 5000 events and plot it on the frame
   RooDataSet *dataSel = (RooDataSet *)data->reduce(CutRange("alt"), EventRange(0, 5000));
   dataSel->plotOn(xframe, MarkerColor(kGreen), LineColor(kGreen));

   new TCanvas("rf405_realtocatfuncs", "rf405_realtocatfuncs", 600, 600);
   xframe->SetMinimum(0.01);
   gPad->SetLeftMargin(0.15);
   xframe->GetYaxis()->SetTitleOffset(1.4);
   xframe->Draw();
}