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rf105_funcbinding.C File Reference
RooFit Tutorials

Detailed Description

'BASIC FUNCTIONALITY' RooFit tutorial macro #105

Demonstration of binding ROOT Math functions as RooFit functions and pdfs

pict1_rf105_funcbinding.C.png
Processing /builddir/build/BUILD/root-6.10.00/tutorials/roofit/rf105_funcbinding.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
RooCFunction1Binding<double,double>::erf[ function=TMath::Erf x=x ] = 0
RooCFunction3PdfBinding<double,double,double,double>::beta[ function=ROOT::Math::beta_pdf x=x2 a=a b=b ] = 0.934689
[#1] INFO:NumericIntegration -- RooRealIntegral::init(beta_Int[x2]) using numeric integrator RooIntegrator1D to calculate Int(x2)
[#1] INFO:NumericIntegration -- RooRealIntegral::init(beta_Int[x2]) using numeric integrator RooIntegrator1D to calculate Int(x2)
[#1] INFO:NumericIntegration -- RooRealIntegral::init(beta_Int[x2]) using numeric integrator RooIntegrator1D to calculate Int(x2)
[#1] INFO:Minization -- RooMinimizer::optimizeConst: activating const optimization
**********
** 1 **SET PRINT 1
**********
**********
** 2 **SET NOGRAD
**********
PARAMETER DEFINITIONS:
NO. NAME VALUE STEP SIZE LIMITS
1 a 5.00000e+00 1.00000e+00 0.00000e+00 1.00000e+01
2 b 2.00000e+00 1.00000e+00 0.00000e+00 1.00000e+01
**********
** 3 **SET ERR 0.5
**********
**********
** 4 **SET PRINT 1
**********
**********
** 5 **SET STR 1
**********
NOW USING STRATEGY 1: TRY TO BALANCE SPEED AGAINST RELIABILITY
**********
** 6 **MIGRAD 1000 1
**********
FIRST CALL TO USER FUNCTION AT NEW START POINT, WITH IFLAG=4.
START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT. 1.00e-03
FCN=-4851.7 FROM MIGRAD STATUS=INITIATE 10 CALLS 11 TOTAL
EDM= unknown STRATEGY= 1 NO ERROR MATRIX
EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 a 5.00000e+00 1.00000e+00 2.01358e-01 -5.86406e+01
2 b 2.00000e+00 1.00000e+00 2.57889e-01 3.98974e+02
ERR DEF= 0.5
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-4851.9 FROM MIGRAD STATUS=CONVERGED 39 CALLS 40 TOTAL
EDM=4.45662e-07 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 a 4.99036e+00 7.12139e-02 3.69873e-04 8.65174e-02
2 b 1.98812e+00 2.63908e-02 1.71677e-04 -1.47761e-01
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 25 NPAR= 2 ERR DEF=0.5
5.072e-03 1.582e-03
1.582e-03 6.965e-04
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2
1 0.84198 1.000 0.842
2 0.84198 0.842 1.000
**********
** 7 **SET ERR 0.5
**********
**********
** 8 **SET PRINT 1
**********
**********
** 9 **HESSE 1000
**********
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=-4851.9 FROM HESSE STATUS=OK 10 CALLS 50 TOTAL
EDM=4.46008e-07 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER INTERNAL INTERNAL
NO. NAME VALUE ERROR STEP SIZE VALUE
1 a 4.99036e+00 7.12317e-02 7.39745e-05 -1.92762e-03
2 b 1.98812e+00 2.63974e-02 3.43355e-05 -6.46475e-01
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 25 NPAR= 2 ERR DEF=0.5
5.074e-03 1.583e-03
1.583e-03 6.968e-04
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2
1 0.84207 1.000 0.842
2 0.84207 0.842 1.000
[#1] INFO:Minization -- RooMinimizer::optimizeConst: deactivating const optimization
[#1] INFO:NumericIntegration -- RooRealIntegral::init(beta_Int[x2]) using numeric integrator RooIntegrator1D to calculate Int(x2)
RooTFnBinding::fa1[ TFn={fa1=sin(x)/x} obs=(x3) ] = -0.0547936
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "TMath.h"
#include "TF1.h"
#include "Math/DistFunc.h"
#include "RooTFnBinding.h"
using namespace RooFit;
void rf105_funcbinding()
{
// B i n d T M a t h : : E r f C f u n c t i o n
// ---------------------------------------------------
// Bind one-dimensional TMath::Erf function as RooAbsReal function
RooRealVar x("x","x",-3,3) ;
RooAbsReal* errorFunc = bindFunction("erf",TMath::Erf,x) ;
// Print erf definition
errorFunc->Print() ;
// Plot erf on frame
RooPlot* frame1 = x.frame(Title("TMath::Erf bound as RooFit function")) ;
errorFunc->plotOn(frame1) ;
// B i n d R O O T : : M a t h : : b e t a _ p d f C f u n c t i o n
// -----------------------------------------------------------------------
// Bind pdf ROOT::Math::Beta with three variables as RooAbsPdf function
RooRealVar x2("x2","x2",0,0.999) ;
RooRealVar a("a","a",5,0,10) ;
RooRealVar b("b","b",2,0,10) ;
RooAbsPdf* beta = bindPdf("beta",ROOT::Math::beta_pdf,x2,a,b) ;
// Perf beta definition
beta->Print() ;
// Generate some events and fit
RooDataSet* data = beta->generate(x2,10000) ;
beta->fitTo(*data) ;
// Plot data and pdf on frame
RooPlot* frame2 = x2.frame(Title("ROOT::Math::Beta bound as RooFit pdf")) ;
data->plotOn(frame2) ;
beta->plotOn(frame2) ;
// B i n d R O O T T F 1 a s R o o F i t f u n c t i o n
// ---------------------------------------------------------------
// Create a ROOT TF1 function
TF1 *fa1 = new TF1("fa1","sin(x)/x",0,10);
// Create an observable
RooRealVar x3("x3","x3",0.01,20) ;
// Create binding of TF1 object to above observable
RooAbsReal* rfa1 = bindFunction(fa1,x3) ;
// Print rfa1 definition
rfa1->Print() ;
// Make plot frame in observable, plot TF1 binding function
RooPlot* frame3 = x3.frame(Title("TF1 bound as RooFit function")) ;
rfa1->plotOn(frame3) ;
TCanvas* c = new TCanvas("rf105_funcbinding","rf105_funcbinding",1200,400) ;
c->Divide(3) ;
c->cd(1) ; gPad->SetLeftMargin(0.15) ; frame1->GetYaxis()->SetTitleOffset(1.6) ; frame1->Draw() ;
c->cd(2) ; gPad->SetLeftMargin(0.15) ; frame2->GetYaxis()->SetTitleOffset(1.6) ; frame2->Draw() ;
c->cd(3) ; gPad->SetLeftMargin(0.15) ; frame3->GetYaxis()->SetTitleOffset(1.6) ; frame3->Draw() ;
}
Author
07/2008 - Wouter Verkerke

Definition in file rf105_funcbinding.C.