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Reference Guide
rf510_wsnamedsets.C File Reference
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View in nbviewer Open in SWAN 'ORGANIZATION AND SIMULTANEOUS FITS' RooFit tutorial macro #510

Working with named parameter sets and parameter snapshots in workspaces

pict1_rf510_wsnamedsets.C.png
Processing /mnt/build/workspace/root-makedoc-v612/rootspi/rdoc/src/v6-12-00-patches/tutorials/roofit/rf510_wsnamedsets.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
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooAddPdf::model
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooChebychev::bkg
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::x
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::a0
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::a1
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::bkgfrac
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooAddPdf::sig
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooGaussian::sig1
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::mean
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::sigma1
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::sig1frac
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooGaussian::sig2
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::sigma2
[#1] INFO:Minization -- RooMinimizer::optimizeConst: activating const optimization
[#1] INFO:Minization -- The following expressions will be evaluated in cache-and-track mode: (bkg,sig1,sig2)
[#1] INFO:Minization -- RooMinimizer::optimizeConst: deactivating const optimization
[#1] INFO:Minization -- RooMinimizer::optimizeConst: activating const optimization
[#1] INFO:Minization -- The following expressions will be evaluated in cache-and-track mode: (bkg,sig1,sig2)
[#1] INFO:Minization -- RooMinimizer::optimizeConst: deactivating const optimization
[#1] INFO:Minization -- createNLL: caching constraint set under name CONSTR_OF_PDF_model_FOR_OBS_x with 0 entries
[#1] INFO:Minization -- RooMinimizer::optimizeConst: activating const optimization
[#1] INFO:Minization -- The following expressions will be evaluated in cache-and-track mode: (bkg,sig1,sig2)
**********
** 1 **SET PRINT 1
**********
**********
** 2 **SET NOGRAD
**********
PARAMETER DEFINITIONS:
NO. NAME VALUE STEP SIZE LIMITS
1 a0 5.00000e-01 1.00000e-01 0.00000e+00 1.00000e+00
2 a1 2.00000e-01 1.00000e-01 0.00000e+00 1.00000e+00
3 bkgfrac 5.00000e-01 1.00000e-01 0.00000e+00 1.00000e+00
4 mean 5.00000e+00 1.00000e+00 0.00000e+00 1.00000e+01
5 sig1frac 8.00000e-01 1.00000e-01 0.00000e+00 1.00000e+00
**********
** 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 2500 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=1953.02 FROM MIGRAD STATUS=INITIATE 14 CALLS 15 TOTAL
EDM= unknown STRATEGY= 1 NO ERROR MATRIX
EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 a0 5.00000e-01 1.00000e-01 2.01358e-01 -5.24449e+00
2 a1 2.00000e-01 1.00000e-01 2.57889e-01 -8.31158e+00
3 bkgfrac 5.00000e-01 1.00000e-01 2.01358e-01 -1.67086e+01
4 mean 5.00000e+00 1.00000e+00 2.01358e-01 -1.20616e+02
5 sig1frac 8.00000e-01 1.00000e-01 2.57889e-01 -8.99606e+00
ERR DEF= 0.5
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=1949.67 FROM MIGRAD STATUS=CONVERGED 164 CALLS 165 TOTAL
EDM=2.46934e-05 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 a0 5.35942e-01 6.82140e-02 4.16868e-03 9.78465e-04
2 a1 1.95503e-01 7.79188e-02 5.51158e-03 2.08158e-03
3 bkgfrac 5.40925e-01 2.13219e-02 1.19176e-03 1.14661e-02
4 mean 5.01914e+00 2.93156e-02 1.77988e-04 4.20703e-01
5 sig1frac 9.99993e-01 6.58597e-01 3.40053e-02 -3.59510e-03
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 25 NPAR= 5 ERR DEF=0.5
4.682e-03 1.464e-04 -2.241e-05 -1.666e-04 1.597e-06
1.464e-04 6.151e-03 -6.777e-04 -1.233e-04 1.335e-05
-2.241e-05 -6.777e-04 4.549e-04 1.230e-05 -4.750e-06
-1.666e-04 -1.233e-04 1.230e-05 8.594e-04 -6.227e-08
1.597e-06 1.335e-05 -4.750e-06 -6.227e-08 9.468e-06
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3 4 5
1 0.08648 1.000 0.027 -0.015 -0.083 0.008
2 0.40890 0.027 1.000 -0.405 -0.054 0.055
3 0.40825 -0.015 -0.405 1.000 0.020 -0.072
4 0.09773 -0.083 -0.054 0.020 1.000 -0.001
5 0.07801 0.008 0.055 -0.072 -0.001 1.000
**********
** 7 **SET ERR 0.5
**********
**********
** 8 **SET PRINT 1
**********
**********
** 9 **HESSE 2500
**********
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=1949.67 FROM HESSE STATUS=OK 31 CALLS 196 TOTAL
EDM=2.47191e-05 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER INTERNAL INTERNAL
NO. NAME VALUE ERROR STEP SIZE VALUE
1 a0 5.35942e-01 6.82123e-02 1.66747e-04 7.19468e-02
2 a1 1.95503e-01 7.77468e-02 2.20463e-04 -6.54793e-01
3 bkgfrac 5.40925e-01 2.12519e-02 2.38351e-04 8.19410e-02
4 mean 5.01914e+00 2.93147e-02 3.55975e-05 3.82861e-03
5 sig1frac 9.99993e-01 6.60187e-01 6.80107e-03 1.56563e+00
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 25 NPAR= 5 ERR DEF=0.5
4.682e-03 1.450e-04 -2.161e-05 -1.666e-04 -2.406e-07
1.450e-04 6.124e-03 -6.677e-04 -1.218e-04 -2.003e-06
-2.161e-05 -6.677e-04 4.519e-04 1.192e-05 7.150e-07
-1.666e-04 -1.218e-04 1.192e-05 8.594e-04 9.372e-09
-2.406e-07 -2.003e-06 7.150e-07 9.372e-09 9.576e-06
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2 3 4 5
1 0.08622 1.000 0.027 -0.015 -0.083 -0.001
2 0.40431 0.027 1.000 -0.401 -0.053 -0.008
3 0.40145 -0.015 -0.401 1.000 0.019 0.011
4 0.09742 -0.083 -0.053 0.019 1.000 0.000
5 0.01172 -0.001 -0.008 0.011 0.000 1.000
[#1] INFO:Minization -- RooMinimizer::optimizeConst: deactivating const optimization
RooWorkspace(w) w contents
variables
---------
(a0,a1,bkgfrac,mean,sig1frac,sigma1,sigma2,x)
p.d.f.s
-------
RooChebychev::bkg[ x=x coefList=(a0,a1) ] = 1
RooAddPdf::model[ bkgfrac * bkg + [%] * sig ] = 1
RooAddPdf::sig[ sig1frac * sig1 + [%] * sig2 ] = 0.0106966
RooGaussian::sig1[ x=x mean=mean sigma=sigma1 ] = 1.19649e-05
RooGaussian::sig2[ x=x mean=mean sigma=sigma2 ] = 0.0588136
parameter snapshots
-------------------
reference_fit = (a0=0.500958 +/- 0.0231941,a1=0.160483 +/- 0.0372743,bkgfrac=0.504708 +/- 0.0113925,mean=5.01893 +/- 0.0101204,sigma1=0.5[C],sig1frac=0.818293 +/- 0.0374313,sigma2=1[C])
reference_fit_bkgonly = (a0=0.474267 +/- 0.0211215,a1=2.86676e-12 +/- 0.000176662,bkgfrac=1[C],mean=2.6195 +/- 2.39943,sigma1=0.5[C],sig1frac=0.818293 +/- 0.324473,sigma2=1[C])
named sets
----------
observables:(x)
parameters:(a0,a1,bkgfrac,mean,sig1frac,sigma1,sigma2)
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooChebychev.h"
#include "RooAddPdf.h"
#include "RooWorkspace.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TFile.h"
#include "TH1.h"
using namespace RooFit;
void fillWorkspace(RooWorkspace& w) ;
void rf510_wsnamedsets()
{
// C r e a t e m o d e l a n d d a t a s e t
// -----------------------------------------------
RooWorkspace* w = new RooWorkspace("w") ;
fillWorkspace(*w) ;
// Exploit convention encoded in named set "parameters" and "observables"
// to use workspace contents w/o need for introspected
RooAbsPdf* model = w->pdf("model") ;
// Generate data from p.d.f. in given observables
RooDataSet* data = model->generate(*w->set("observables"),1000) ;
// Fit model to data
model->fitTo(*data) ;
// Plot fitted model and data on frame of first (only) observable
RooPlot* frame = ((RooRealVar*)w->set("observables")->first())->frame() ;
data->plotOn(frame) ;
model->plotOn(frame) ;
// Overlay plot with model with reference parameters as stored in snapshots
w->loadSnapshot("reference_fit") ;
model->plotOn(frame,LineColor(kRed)) ;
w->loadSnapshot("reference_fit_bkgonly") ;
model->plotOn(frame,LineColor(kRed),LineStyle(kDashed)) ;
// Draw the frame on the canvas
new TCanvas("rf510_wsnamedsets","rf503_wsnamedsets",600,600) ;
gPad->SetLeftMargin(0.15) ; frame->GetYaxis()->SetTitleOffset(1.4) ; frame->Draw() ;
// Print workspace contents
w->Print() ;
// Workspace will remain in memory after macro finishes
gDirectory->Add(w) ;
}
void fillWorkspace(RooWorkspace& w)
{
// C r e a t e m o d e l
// -----------------------
// 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",5,0,10) ;
RooRealVar sigma1("sigma1","width of gaussians",0.5) ;
RooRealVar sigma2("sigma2","width of gaussians",1) ;
RooGaussian sig1("sig1","Signal component 1",x,mean,sigma1) ;
RooGaussian sig2("sig2","Signal component 2",x,mean,sigma2) ;
// Build Chebychev polynomial p.d.f.
RooRealVar a0("a0","a0",0.5,0.,1.) ;
RooRealVar a1("a1","a1",0.2,0.,1.) ;
RooChebychev bkg("bkg","Background",x,RooArgSet(a0,a1)) ;
// Sum the signal components into a composite signal p.d.f.
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) ;
// Import model into p.d.f.
w.import(model) ;
// E n c o d e d e f i n i t i o n o f p a r a m e t e r s i n w o r k s p a c e
// ---------------------------------------------------------------------------------------
// Define named sets "parameters" and "observables", which list which variables should be considered
// parameters and observables by the users convention
//
// Variables appearing in sets _must_ live in the workspace already, or the autoImport flag
// of defineSet must be set to import them on the fly. Named sets contain only references
// to the original variables, therefore the value of observables in named sets already
// reflect their 'current' value
RooArgSet* params = (RooArgSet*) model.getParameters(x) ;
w.defineSet("parameters",*params) ;
w.defineSet("observables",x) ;
// E n c o d e r e f e r e n c e v a l u e f o r p a r a m e t e r s i n w o r k s p a c e
// ---------------------------------------------------------------------------------------------------
// Define a parameter 'snapshot' in the p.d.f.
// Unlike a named set, a parameter snapshot stores an independent set of values for
// a given set of variables in the workspace. The values can be stored and reloaded
// into the workspace variable objects using the loadSnapshot() and saveSnapshot()
// methods. A snapshot saves the value of each variable, any errors that are stored
// with it as well as the 'Constant' flag that is used in fits to determine if a
// parameter is kept fixed or not.
// Do a dummy fit to a (supposedly) reference dataset here and store the results
// of that fit into a snapshot
RooDataSet* refData = model.generate(x,10000) ;
model.fitTo(*refData,PrintLevel(-1)) ;
// The kTRUE flag imports the values of the objects in (*params) into the workspace
// If not set, the present values of the workspace parameters objects are stored
w.saveSnapshot("reference_fit",*params,kTRUE) ;
// Make another fit with the signal component forced to zero
// and save those parameters too
bkgfrac.setVal(1) ;
bkgfrac.setConstant(kTRUE) ;
bkgfrac.removeError() ;
model.fitTo(*refData,PrintLevel(-1)) ;
w.saveSnapshot("reference_fit_bkgonly",*params,kTRUE) ;
}
Author
04/2009 - Wouter Verkerke

Definition in file rf510_wsnamedsets.C.