rf703_effpdfprod.C File Reference

Detailed Description

Special pdf's: using a product of an (acceptance) efficiency and a pdf as pdf

 
 
␛[1mRooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby␛[0m 
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt
 
[#1] INFO:NumericIntegration -- RooRealIntegral::init(modelEff_clone_Int[t]) using numeric integrator RooIntegrator1D to calculate Int(t)
[#1] INFO:NumericIntegration -- RooRealIntegral::init(modelEff_clone_Int[t]) using numeric integrator RooIntegrator1D to calculate Int(t)
[#1] INFO:Minization -- RooMinimizer::optimizeConst: activating const optimization
[#1] INFO:Minization --  The following expressions have been identified as constant and will be precalculated and cached: (eff)
 **********
 **    1 **SET PRINT           1
 **********
 **********
 **    2 **SET NOGRAD
 **********
 PARAMETER DEFINITIONS:
    NO.   NAME         VALUE      STEP SIZE      LIMITS
     1 tau         -1.54000e+00  3.90000e-01   -4.00000e+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         500           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=9696.74 FROM MIGRAD    STATUS=INITIATE        4 CALLS           5 TOTAL
                     EDM= unknown      STRATEGY= 1      NO ERROR MATRIX       
  EXT PARAMETER               CURRENT GUESS       STEP         FIRST   
  NO.   NAME      VALUE            ERROR          SIZE      DERIVATIVE 
   1  tau         -1.54000e+00   3.90000e-01   2.09076e-01   1.80888e+02
                               ERR DEF= 0.5
 MIGRAD MINIMIZATION HAS CONVERGED.
 MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
 COVARIANCE MATRIX CALCULATED SUCCESSFULLY
 FCN=9695.84 FROM MIGRAD    STATUS=CONVERGED      12 CALLS          13 TOTAL
                     EDM=2.41592e-05    STRATEGY= 1      ERROR MATRIX ACCURATE 
  EXT PARAMETER                                   STEP         FIRST   
  NO.   NAME      VALUE            ERROR          SIZE      DERIVATIVE 
   1  tau         -1.55887e+00   1.40931e-02   5.05936e-04   6.58163e-01
                               ERR DEF= 0.5
 EXTERNAL ERROR MATRIX.    NDIM=  25    NPAR=  1    ERR DEF=0.5
  1.986e-04 
 **********
 **    7 **SET ERR         0.5
 **********
 **********
 **    8 **SET PRINT           1
 **********
 **********
 **    9 **HESSE         500
 **********
 COVARIANCE MATRIX CALCULATED SUCCESSFULLY
 FCN=9695.84 FROM HESSE     STATUS=OK              5 CALLS          18 TOTAL
                     EDM=2.41576e-05    STRATEGY= 1      ERROR MATRIX ACCURATE 
  EXT PARAMETER                                INTERNAL      INTERNAL  
  NO.   NAME      VALUE            ERROR       STEP SIZE       VALUE   
   1  tau         -1.55887e+00   1.40931e-02   1.01187e-04   2.54601e-01
                               ERR DEF= 0.5
 EXTERNAL ERROR MATRIX.    NDIM=  25    NPAR=  1    ERR DEF=0.5
  1.986e-04 
[#1] INFO:Minization -- RooMinimizer::optimizeConst: deactivating const optimization
[#1] INFO:NumericIntegration -- RooRealIntegral::init(modelEff_clone_Int[t]) using numeric integrator RooIntegrator1D to calculate Int(t)

 
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooExponential.h"
#include "RooEffProd.h"
#include "RooFormulaVar.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
using namespace RooFit;
 
void rf703_effpdfprod()
{
   // D e f i n e   o b s e r v a b l e s   a n d   d e c a y   p d f
   // ---------------------------------------------------------------
 
   // Declare observables
   RooRealVar t("t", "t", 0, 5);
 
   // Make pdf
   RooRealVar tau("tau", "tau", -1.54, -4, -0.1);
   RooExponential model("model", "model", t, tau);
 
   // D e f i n e   e f f i c i e n c y   f u n c t i o n
   // ---------------------------------------------------
 
   // Use error function to simulate turn-on slope
   RooFormulaVar eff("eff", "0.5*(TMath::Erf((t-1)/0.5)+1)", t);
 
   // D e f i n e   d e c a y   p d f   w i t h   e f f i c i e n c y
   // ---------------------------------------------------------------
 
   // Multiply pdf(t) with efficiency in t
   RooEffProd modelEff("modelEff", "model with efficiency", model, eff);
 
   // P l o t   e f f i c i e n c y ,   p d f
   // ----------------------------------------
 
   RooPlot *frame1 = t.frame(Title("Efficiency"));
   eff.plotOn(frame1, LineColor(kRed));
 
   RooPlot *frame2 = t.frame(Title("Pdf with and without efficiency"));
 
   model.plotOn(frame2, LineStyle(kDashed));
   modelEff.plotOn(frame2);
 
   // G e n e r a t e   t o y   d a t a ,   f i t   m o d e l E f f   t o   d a t a
   // ------------------------------------------------------------------------------
 
   // Generate events. If the input pdf has an internal generator, the internal generator
   // is used and an accept/reject sampling on the efficiency is applied.
   RooDataSet *data = modelEff.generate(t, 10000);
 
   // Fit pdf. The normalization integral is calculated numerically.
   modelEff.fitTo(*data);
 
   // Plot generated data and overlay fitted pdf
   RooPlot *frame3 = t.frame(Title("Fitted pdf with efficiency"));
   data->plotOn(frame3);
   modelEff.plotOn(frame3);
 
   TCanvas *c = new TCanvas("rf703_effpdfprod", "rf703_effpdfprod", 1200, 400);
   c->Divide(3);
   c->cd(1);
   gPad->SetLeftMargin(0.15);
   frame1->GetYaxis()->SetTitleOffset(1.4);
   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();
}

Date

July 2008

Author

Wouter Verkerke

Definition in file rf703_effpdfprod.C.