doc/hackathon/rf607__fitresult_8C.html

#include "RooRealVar.h"

#include "RooDataSet.h"

#include "RooGaussian.h"

#include "RooAddPdf.h"

#include "RooChebychev.h"

#include "RooFitResult.h"

#include "TCanvas.h"

#include "TAxis.h"

#include "RooPlot.h"

#include "TFile.h"

#include "TStyle.h"

#include "TH2.h"

#include "TMatrixDSym.h"


using namespace RooFit;


void rf607_fitresult()

{

   // C r e a t e   p d f ,   d a t a

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


   // 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, -10, 10);

   RooRealVar sigma1("sigma1", "width of gaussians", 0.5, 0.1, 10);

   RooRealVar sigma2("sigma2", "width of gaussians", 1, 0.1, 10);


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

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


   // Build Chebychev polynomial pdf

   RooRealVar a0("a0", "a0", 0.5, 0., 1.);

   RooRealVar a1("a1", "a1", -0.2);

   RooChebychev bkg("bkg", "Background", x, RooArgSet(a0, a1));


   // Sum the signal components into a composite signal pdf

   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);


   // Generate 1000 events

   std::unique_ptr<RooDataSet> data{model.generate(x, 1000)};


   // F i t   p d f   t o   d a t a ,   s a v e   f i t r e s u l t

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


   // Perform fit and save result

   std::unique_ptr<RooFitResult> r{model.fitTo(*data, Save(), PrintLevel(-1))};


   // P r i n t   f i t   r e s u l t s

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


   // Summary printing: Basic info plus final values of floating fit parameters

   r->Print();


   // Verbose printing: Basic info, values of constant parameters, initial and

   // final values of floating parameters, global correlations

   r->Print("v");


   // V i s u a l i z e   c o r r e l a t i o n   m a t r i x

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


   // Construct 2D color plot of correlation matrix

   gStyle->SetOptStat(0);

   TH2 *hcorr = r->correlationHist();


   // Visualize ellipse corresponding to single correlation matrix element

   RooPlot *frame = new RooPlot(sigma1, sig1frac, 0.45, 0.60, 0.65, 0.90);

   frame->SetTitle("Covariance between sigma1 and sig1frac");

   r->plotOn(frame, sigma1, sig1frac, "ME12ABHV");


   // A c c e s s   f i t   r e s u l t   i n f o r m a t i o n

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


   // Access basic information

   cout << "EDM = " << r->edm() << endl;

   cout << "-log(L) at minimum = " << r->minNll() << endl;


   // Access list of final fit parameter values

   cout << "final value of floating parameters" << endl;

   r->floatParsFinal().Print("s");


   // Access correlation matrix elements

   cout << "correlation between sig1frac and a0 is  " << r->correlation(sig1frac, a0) << endl;

   cout << "correlation between bkgfrac and mean is " << r->correlation("bkgfrac", "mean") << endl;


   // Extract covariance and correlation matrix as TMatrixDSym

   const TMatrixDSym &cor = r->correlationMatrix();

   const TMatrixDSym &cov = r->covarianceMatrix();


   // Print correlation, covariance matrix

   cout << "correlation matrix" << endl;

   cor.Print();

   cout << "covariance matrix" << endl;

   cov.Print();


   // P e r s i s t   f i t   r e s u l t   i n   r o o t   f i l e

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


   // Open new ROOT file save save result

   TFile f("rf607_fitresult.root", "RECREATE");

   r->Write("rf607");

   f.Close();


   // In a clean ROOT session retrieve the persisted fit result as follows:

   // RooFitResult* r = gDirectory->Get("rf607") ;


   TCanvas *c = new TCanvas("rf607_fitresult", "rf607_fitresult", 800, 400);

   c->Divide(2);

   c->cd(1);

   gPad->SetLeftMargin(0.15);

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

   hcorr->Draw("colz");

   c->cd(2);

   gPad->SetLeftMargin(0.15);

   frame->GetYaxis()->SetTitleOffset(1.6);

   frame->Draw();

}

r
ROOT::R::TRInterface & r
Definition Object.C:4

f
#define f(i)
Definition RSha256.hxx:104

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

RooAddPdf.h

RooChebychev.h

RooDataSet.h

RooFitResult.h

RooGaussian.h

RooPlot.h

RooRealVar.h

TAxis.h

TCanvas.h

TFile.h

TH2.h

TMatrixDSym.h

TMatrixDSym
TMatrixTSym< Double_t > TMatrixDSym
Definition TMatrixDSymfwd.h:23

TStyle.h

gStyle
externTStyle * gStyle
Definition TStyle.h:442

gPad
#define gPad
Definition TVirtualPad.h:322

RooAddPdf
Efficient implementation of a sum of PDFs of the form.
Definition RooAddPdf.h:33

RooArgList
RooArgList is a container object that can hold multiple RooAbsArg objects.
Definition RooArgList.h:22

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

RooChebychev
Chebychev polynomial p.d.f.
Definition RooChebychev.h:25

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::SetTitle
void SetTitle(const char *name) override
Set the title of the RooPlot to 'title'.
Definition RooPlot.cxx:1209

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

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

TFile
A file, usually with extension .root, that stores data and code in the form of serialized objects in ...
Definition TFile.h:130

TH1::GetYaxis
TAxis * GetYaxis()
Definition TH1.h:572

TH1::Draw
void Draw(Option_t *option="") override
Draw this histogram with options.
Definition TH1.cxx:3097

TH2
Service class for 2-D histogram classes.
Definition TH2.h:30

TMatrixTBase::Print
void Print(Option_t *name="") const override
Print the matrix as a table of elements.
Definition TMatrixTBase.cxx:635

RooFit::Save
RooCmdArg Save(bool flag=true)
Definition RooGlobalFunc.cxx:651

RooFit::PrintLevel
RooCmdArg PrintLevel(Int_t code)
Definition RooGlobalFunc.cxx:659

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

rf607_fitresult
Definition rf607_fitresult.py:1