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Reference Guide
rf902_numgenconfig.C File Reference

Detailed Description

View in nbviewer Open in SWAN 'NUMERIC ALGORITHM TUNING' RooFit tutorial macro #902

Configuration and customization of how MC sampling algorithms on specific p.d.f.s are executed

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Processing /mnt/build/workspace/root-makedoc-v614/rootspi/rdoc/src/v6-14-00-patches/tutorials/roofit/rf902_numgenconfig.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
--- RooGenContext ---
Using PDF RooChebychev::model[ x=x coefList=(0,0.5,-0.1) ]
Use PDF generator for ()
Use MC sampling generator RooAcceptReject for (x)
RooDataSet::modelData[x] = 10000 entries
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
F F
F **************************************** F
F ****** TFoam::Initialize ****** F
F **************************************** F
F TFOAM F
F Version = 1.02M = Release date: 2005.04.10 F
F kDim = 1 = Dimension of the hyper-cubical space F
F nCells = 30 = Requested number of Cells (half of them active) F
F nSampl = 200 = No of MC events in exploration of a cell F
F nBin = 8 = No of bins in histograms, MC exploration of cell F
F EvPerBin = 25 = Maximum No effective_events/bin, MC exploration F
F OptDrive = 2 = Type of Driver =1,2 for Sigma,WtMax F
F OptRej = 1 = MC rejection on/off for OptRej=0,1 F
F MaxWtRej = 1.1 = Maximum wt in rejection for wt=1 evts F
F F
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
11
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
F F
F *** TFoam::Initialize FINISHED!!! *** F
F nCalls = 5800 = Total number of function calls F
F XPrime = 0.1100962 = Primary total integral F
F XDiver = 0.010134446 = Driver total integral F
F mcResult = 0.099961756 = Estimate of the true MC Integral F
F F
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
--- RooGenContext ---
Using PDF RooChebychev::model[ x=x coefList=(0,0.5,-0.1) ]
Use PDF generator for ()
Use MC sampling generator RooFoamGenerator for (x)
RooDataSet::modelData[x] = 10000 entries
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooConstVar.h"
#include "RooChebychev.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "RooArgSet.h"
#include <iomanip>
using namespace RooFit ;
void rf902_numgenconfig()
{
// A d j u s t g l o b a l MC s a m p l i n g s t r a t e g y
// ------------------------------------------------------------------
// Example p.d.f. for use below
RooRealVar x("x","x",0,10) ;
RooChebychev model("model","model",x,RooArgList(RooConst(0),RooConst(0.5),RooConst(-0.1))) ;
// Change global strategy for 1D sampling problems without conditional observable
// (1st kFALSE) and without discrete observable (2nd kFALSE) from RooFoamGenerator,
// ( an interface to the TFoam MC generator with adaptive subdivisioning strategy ) to RooAcceptReject,
// a plain accept/reject sampling algorithm [ RooFit default before ROOT 5.23/04 ]
// Generate 10Kevt using RooAcceptReject
RooDataSet* data_ar = model.generate(x,10000,Verbose(kTRUE)) ;
data_ar->Print() ;
// A d j u s t i n g d e f a u l t c o n f i g f o r a s p e c i f i c p d f
// -------------------------------------------------------------------------------------
// Another possibility: associate custom MC sampling configuration as default for object 'model'
// The kTRUE argument will install a clone of the default configuration as specialized configuration
// for this model if none existed so far
model.specialGeneratorConfig(kTRUE)->method1D(kFALSE,kFALSE).setLabel("RooFoamGenerator") ;
// A d j u s t i n g p a r a m e t e r s o f a s p e c i f i c t e c h n i q u e
// ---------------------------------------------------------------------------------------
// Adjust maximum number of steps of RooIntegrator1D in the global default configuration
RooAbsPdf::defaultGeneratorConfig()->getConfigSection("RooAcceptReject").setRealValue("nTrial1D",2000) ;
// Example of how to change the parameters of a numeric integrator
// (Each config section is a RooArgSet with RooRealVars holding real-valued parameters
// and RooCategories holding parameters with a finite set of options)
model.specialGeneratorConfig()->getConfigSection("RooFoamGenerator").setRealValue("chatLevel",1) ;
// Generate 10Kevt using RooFoamGenerator (FOAM verbosity increased with above chatLevel adjustment for illustration purposes)
RooDataSet* data_foam = model.generate(x,10000,Verbose()) ;
data_foam->Print() ;
}
Author
07/2008 - Wouter Verkerke

Definition in file rf902_numgenconfig.C.