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Reference Guide
rf108_plotbinning.C File Reference

Detailed Description

View in nbviewer Open in SWAN 'BASIC FUNCTIONALITY' RooFit tutorial macro #108

Plotting unbinned data with alternate and variable binnings

pict1_rf108_plotbinning.C.png
Processing /mnt/build/workspace/root-makedoc-v614/rootspi/rdoc/src/v6-14-00-patches/tutorials/roofit/rf108_plotbinning.C...
RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby
Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
All rights reserved, please read http://roofit.sourceforge.net/license.txt
[#1] INFO:Plotting -- RooAbsReal::plotOn(bmix) plot on dt integrates over variables (mixState,tagFlav)
[#1] INFO:Plotting -- RooAbsReal::plotAsymOn(bmix) plot on dt projects variables (tagFlav)
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussModel.h"
#include "RooDecay.h"
#include "RooBMixDecay.h"
#include "RooCategory.h"
#include "RooBinning.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit ;
void rf108_plotbinning()
{
// S e t u p m o d e l
// ---------------------
// Build a B decay p.d.f with mixing
RooRealVar dt("dt","dt",-20,20) ;
RooRealVar dm("dm","dm",0.472) ;
RooRealVar tau("tau","tau",1.547) ;
RooRealVar w("w","mistag rate",0.1) ;
RooRealVar dw("dw","delta mistag rate",0.) ;
RooCategory mixState("mixState","B0/B0bar mixing state") ;
mixState.defineType("mixed",-1) ;
mixState.defineType("unmixed",1) ;
RooCategory tagFlav("tagFlav","Flavour of the tagged B0") ;
tagFlav.defineType("B0",1) ;
tagFlav.defineType("B0bar",-1) ;
// Build a gaussian resolution model
RooRealVar bias1("bias1","bias1",0) ;
RooRealVar sigma1("sigma1","sigma1",0.1) ;
RooGaussModel gm1("gm1","gauss model 1",dt,bias1,sigma1) ;
// Construct Bdecay (x) gauss
RooBMixDecay bmix("bmix","decay",dt,mixState,tagFlav,tau,dm,w,dw,gm1,RooBMixDecay::DoubleSided) ;
// S a m p l e d a t a f r o m m o d e l
// --------------------------------------------
// Sample 2000 events in (dt,mixState,tagFlav) from bmix
RooDataSet *data = bmix.generate(RooArgSet(dt,mixState,tagFlav),2000) ;
// S h o w d t d i s t r i b u t i o n w i t h c u s t o m b i n n i n g
// -------------------------------------------------------------------------------
// Make plot of dt distribution of data in range (-15,15) with fine binning for dt>0 and coarse binning for dt<0
// Create binning object with range (-15,15)
RooBinning tbins(-15,15) ;
// Add 60 bins with uniform spacing in range (-15,0)
tbins.addUniform(60,-15,0) ;
// Add 15 bins with uniform spacing in range (0,15)
tbins.addUniform(15,0,15) ;
// Make plot with specified binning
RooPlot* dtframe = dt.frame(Range(-15,15),Title("dt distribution with custom binning")) ;
data->plotOn(dtframe,Binning(tbins)) ;
bmix.plotOn(dtframe) ;
// NB: Note that bin density for each bin is adjusted to that of default frame binning as shown
// in Y axis label (100 bins --> Events/0.4*Xaxis-dim) so that all bins represent a consistent density distribution
// S h o w m i x s t a t e a s y m m e t r y w i t h c u s t o m b i n n i n g
// ------------------------------------------------------------------------------------
// Make plot of dt distribution of data asymmetry in 'mixState' with variable binning
// Create binning object with range (-10,10)
RooBinning abins(-10,10) ;
// Add boundaries at 0, (-1,1), (-2,2), (-3,3), (-4,4) and (-6,6)
abins.addBoundary(0) ;
abins.addBoundaryPair(1) ;
abins.addBoundaryPair(2) ;
abins.addBoundaryPair(3) ;
abins.addBoundaryPair(4) ;
abins.addBoundaryPair(6) ;
// Create plot frame in dt
RooPlot* aframe = dt.frame(Range(-10,10),Title("mixState asymmetry distribution with custom binning")) ;
// Plot mixState asymmetry of data with specified custom binning
data->plotOn(aframe,Asymmetry(mixState),Binning(abins)) ;
// Plot corresponding property of p.d.f
bmix.plotOn(aframe,Asymmetry(mixState)) ;
// Adjust vertical range of plot to sensible values for an asymmetry
aframe->SetMinimum(-1.1) ;
aframe->SetMaximum(1.1) ;
// NB: For asymmetry distributions no density corrects are needed (and are thus not applied)
// Draw plots on canvas
TCanvas* c = new TCanvas("rf108_plotbinning","rf108_plotbinning",800,400) ;
c->Divide(2) ;
c->cd(1) ; gPad->SetLeftMargin(0.15) ; dtframe->GetYaxis()->SetTitleOffset(1.6) ; dtframe->Draw() ;
c->cd(2) ; gPad->SetLeftMargin(0.15) ; aframe->GetYaxis()->SetTitleOffset(1.6) ; aframe->Draw() ;
}
Author
07/2008 - Wouter Verkerke

Definition in file rf108_plotbinning.C.