doc/master/rf315__projectpdf_8C.html

#include "RooRealVar.h"

#include "RooDataHist.h"

#include "RooGaussian.h"

#include "RooProdPdf.h"

#include "RooPolyVar.h"

#include "TH1.h"

#include "TCanvas.h"

#include "TAxis.h"

#include "RooPlot.h"

#include "RooNumIntConfig.h"

using namespace RooFit;


void rf315_projectpdf()

{

   // C r e a t e   p d f   m ( x , y )  =  g x ( x | y ) * g ( y )

   // --------------------------------------------------------------


   // Increase default precision of numeric integration

   // as this exercise has high sensitivity to numeric integration precision

   RooAbsPdf::defaultIntegratorConfig()->setEpsRel(1e-8);

   RooAbsPdf::defaultIntegratorConfig()->setEpsAbs(1e-8);


   // Create observables

   RooRealVar x("x", "x", -5, 5);

   RooRealVar y("y", "y", -2, 2);


   // Create function f(y) = a0 + a1*y

   RooRealVar a0("a0", "a0", 0);

   RooRealVar a1("a1", "a1", -1.5, -3, 1);

   RooPolyVar fy("fy", "fy", y, RooArgSet(a0, a1));


   // Create gaussx(x,f(y),sx)

   RooRealVar sigmax("sigmax", "width of gaussian", 0.5);

   RooGaussian gaussx("gaussx", "Gaussian in x with shifting mean in y", x, fy, sigmax);


   // Create gaussy(y,0,2)

   RooGaussian gaussy("gaussy", "Gaussian in y", y, 0.0, 2.0);


   // Create gaussx(x,sx|y) * gaussy(y)

   RooProdPdf model("model", "gaussx(x|y)*gaussy(y)", gaussy, Conditional(gaussx, x));


   // M a r g i n a l i z e   m ( x , y )   t o   m ( x )

   // ----------------------------------------------------


   // modelx(x) = Int model(x,y) dy

   RooAbsPdf *modelx = model.createProjection(y);


   // U s e   m a r g i n a l i z e d   p . d . f .   a s   r e g u l a r   1 - D   p . d . f .

   // ------------------------------------------------------------------------------------------


   // Sample 1000 events from modelx

   std::unique_ptr<RooAbsData> data{modelx->generateBinned(x, 1000)};


   // Fit modelx to toy data

   modelx->fitTo(*data, Verbose(), PrintLevel(-1));


   // Plot modelx over data

   RooPlot *frame = x.frame(40);

   data->plotOn(frame);

   modelx->plotOn(frame);


   // Make 2D histogram of model(x,y)

   TH1 *hh = model.createHistogram("x,y");

   hh->SetLineColor(kBlue);


   TCanvas *c = new TCanvas("rf315_projectpdf", "rf315_projectpdf", 800, 400);

   c->Divide(2);

   c->cd(1);

   gPad->SetLeftMargin(0.15);

   frame->GetYaxis()->SetTitleOffset(1.4);

   frame->Draw();

   c->cd(2);

   gPad->SetLeftMargin(0.20);

   hh->GetZaxis()->SetTitleOffset(2.5);

   hh->Draw("surf");

}

c
#define c(i)
Definition RSha256.hxx:101

e
#define e(i)
Definition RSha256.hxx:103

RooDataHist.h

RooGaussian.h

RooNumIntConfig.h

RooPlot.h

RooPolyVar.h

RooProdPdf.h

RooRealVar.h

kBlue
@ kBlue
Definition Rtypes.h:67

TAxis.h

TCanvas.h

TRangeDynCast
ROOT::Detail::TRangeCast< T, true > TRangeDynCast
TRangeDynCast is an adapter class that allows the typed iteration through a TCollection.
Definition TCollection.h:360

data
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void data
Definition TGWin32VirtualXProxy.cxx:104

TH1.h

gPad
#define gPad
Definition TVirtualPad.h:322

ROOT::Detail::TRangeCast
Definition TCollection.h:313

RooAbsPdf
Abstract interface for all probability density functions.
Definition RooAbsPdf.h:32

RooAbsReal::defaultIntegratorConfig
static RooNumIntConfig * defaultIntegratorConfig()
Returns the default numeric integration configuration for all RooAbsReals.
Definition RooAbsReal.cxx:3182

RooArgSet
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition RooArgSet.h:24

RooGaussian
Plain Gaussian p.d.f.
Definition RooGaussian.h:24

RooPlot
Plot frame and a container for graphics objects within that frame.
Definition RooPlot.h:43

RooPlot::frame
static RooPlot * frame(const RooAbsRealLValue &var, double xmin, double xmax, Int_t nBins)
Create a new frame for a given variable in x.
Definition RooPlot.cxx:185

RooPlot::GetYaxis
TAxis * GetYaxis() const
Definition RooPlot.cxx:1230

RooPlot::Draw
void Draw(Option_t *options=nullptr) override
Draw this plot and all of the elements it contains.
Definition RooPlot.cxx:597

RooPolyVar
A RooAbsReal implementing a polynomial in terms of a list of RooAbsReal coefficients.
Definition RooPolyVar.h:25

RooProdPdf
Efficient implementation of a product of PDFs of the form.
Definition RooProdPdf.h:36

RooRealVar
Variable that can be changed from the outside.
Definition RooRealVar.h:37

TAttAxis::SetTitleOffset
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition TAttAxis.cxx:279

TCanvas
The Canvas class.
Definition TCanvas.h:23

TH1
TH1 is the base class of all histogram classes in ROOT.
Definition TH1.h:109

y
Double_t y[n]
Definition legend1.C:17

x
Double_t x[n]
Definition legend1.C:17

RooFit
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
Definition CodegenImpl.h:72

rf315_projectpdf
Definition rf315_projectpdf.py:1