doc/hackathon/rf510__wsnamedsets_8C.html

#include "RooRealVar.h"

#include "RooDataSet.h"

#include "RooGaussian.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 pdf in given observables

   std::unique_ptr<RooDataSet> data{model->generate(*w->set("observables"), 1000)};


   // Fit model to data

   model->fitTo(*data, PrintLevel(-1));


   // 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 pdf

   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 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);


   // Import model into pdf

   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

   std::unique_ptr<RooArgSet> params{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 pdf

   // 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

   std::unique_ptr<RooDataSet> refData{model.generate(x, 10000)};

   model.fitTo(*refData, PrintLevel(-1));


   // The true 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, true);


   // Make another fit with the signal component forced to zero

   // and save those parameters too


   bkgfrac.setVal(1);

   bkgfrac.setConstant(true);

   bkgfrac.removeError();

   model.fitTo(*refData, PrintLevel(-1));


   w.saveSnapshot("reference_fit_bkgonly", *params, true);

}

RooAddPdf.h

RooChebychev.h

RooDataSet.h

RooGaussian.h

RooPlot.h

RooRealVar.h

RooWorkspace.h

kRed
@ kRed
Definition Rtypes.h:67

kDashed
@ kDashed
Definition TAttLine.h:54

TAxis.h

TCanvas.h

gDirectory
#define gDirectory
Definition TDirectory.h:385

TFile.h

TH1.h

gPad
#define gPad
Definition TVirtualPad.h:322

RooAbsPdf
Abstract interface for all probability density functions.
Definition RooAbsPdf.h:32

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::frame
static RooPlot * frame(const RooAbsRealLValue &var, double xmin, double xmax, Int_t nBins)
Create a new frame for a given variable in x.
Definition RooPlot.cxx:185

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

RooWorkspace
Persistable container for RooFit projects.
Definition RooWorkspace.h:43

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

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

RooFit::LineColor
RooCmdArg LineColor(TColorNumber color)
Definition RooGlobalFunc.cxx:229

RooFit::LineStyle
RooCmdArg LineStyle(Style_t style)
Definition RooGlobalFunc.cxx:233

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

hist015_TH1_read_and_draw_uhi.mean
mean
Definition hist015_TH1_read_and_draw_uhi.py:34

rf503_wspaceread.w
w
Definition rf503_wspaceread.py:29

rf503_wspaceread.model
model
Definition rf503_wspaceread.py:36

rf510_wsnamedsets
Definition rf510_wsnamedsets.py:1