Logo ROOT   6.08/07
Reference Guide
rf305_condcorrprod.C File Reference

Detailed Description

View in nbviewer Open in SWAN 'MULTIDIMENSIONAL MODELS' RooFit tutorial macro #305

Multi-dimensional p.d.f.s with conditional p.d.fs in product

pdf = gauss(x,f(y),sx | y ) * gauss(y,ms,sx) with f(y) = a0 + a1*y



Processing /mnt/build/workspace/root-makedoc-v608/rootspi/rdoc/src/v6-08-00-patches/tutorials/roofit/rf305_condcorrprod.C...
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooPolyVar.h"
#include "RooProdPdf.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit ;
void rf305_condcorrprod()
{
// C r e a t e c o n d i t i o n a l p d f g x ( x | y )
// -----------------------------------------------------------
// Create observables
RooRealVar x("x","x",-5,5) ;
RooRealVar y("y","y",-5,5) ;
// Create function f(y) = a0 + a1*y
RooRealVar a0("a0","a0",-0.5,-5,5) ;
RooRealVar a1("a1","a1",-0.5,-1,1) ;
RooPolyVar fy("fy","fy",y,RooArgSet(a0,a1)) ;
// Create gaussx(x,f(y),sx)
RooRealVar sigmax("sigma","width of gaussian",0.5) ;
RooGaussian gaussx("gaussx","Gaussian in x with shifting mean in y",x,fy,sigmax) ;
// C r e a t e p d f g y ( y )
// -----------------------------------------------------------
// Create gaussy(y,0,5)
RooGaussian gaussy("gaussy","Gaussian in y",y,RooConst(0),RooConst(3)) ;
// C r e a t e p r o d u c t g x ( x | y ) * g y ( y )
// -------------------------------------------------------
// Create gaussx(x,sx|y) * gaussy(y)
RooProdPdf model("model","gaussx(x|y)*gaussy(y)",gaussy,Conditional(gaussx,x)) ;
// S a m p l e , f i t a n d p l o t p r o d u c t p d f
// ---------------------------------------------------------------
// Generate 1000 events in x and y from model
RooDataSet *data = model.generate(RooArgSet(x,y),10000) ;
// Plot x distribution of data and projection of model on x = Int(dy) model(x,y)
RooPlot* xframe = x.frame() ;
data->plotOn(xframe) ;
model.plotOn(xframe) ;
// Plot x distribution of data and projection of model on y = Int(dx) model(x,y)
RooPlot* yframe = y.frame() ;
data->plotOn(yframe) ;
model.plotOn(yframe) ;
// Make two-dimensional plot in x vs y
TH1* hh_model = model.createHistogram("hh_model",x,Binning(50),YVar(y,Binning(50))) ;
hh_model->SetLineColor(kBlue) ;
// Make canvas and draw RooPlots
TCanvas *c = new TCanvas("rf305_condcorrprod","rf05_condcorrprod",1200, 400);
c->Divide(3);
c->cd(1) ; gPad->SetLeftMargin(0.15) ; xframe->GetYaxis()->SetTitleOffset(1.6) ; xframe->Draw() ;
c->cd(2) ; gPad->SetLeftMargin(0.15) ; yframe->GetYaxis()->SetTitleOffset(1.6) ; yframe->Draw() ;
c->cd(3) ; gPad->SetLeftMargin(0.20) ; hh_model->GetZaxis()->SetTitleOffset(2.5) ; hh_model->Draw("surf") ;
}
Author
07/2008 - Wouter Verkerke

Definition in file rf305_condcorrprod.C.