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rf510_wsnamedsets.C
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1 /// \file
2 /// \ingroup tutorial_roofit
3 /// \notebook -js
4 /// Organization and simultaneous fits: working with named parameter sets and parameter
5 /// snapshots in workspaces
6 ///
7 /// \macro_image
8 /// \macro_output
9 /// \macro_code
10 ///
11 /// \date April 2009
12 /// \author Wouter Verkerke
13 
14 #include "RooRealVar.h"
15 #include "RooDataSet.h"
16 #include "RooGaussian.h"
17 #include "RooConstVar.h"
18 #include "RooChebychev.h"
19 #include "RooAddPdf.h"
20 #include "RooWorkspace.h"
21 #include "RooPlot.h"
22 #include "TCanvas.h"
23 #include "TAxis.h"
24 #include "TFile.h"
25 #include "TH1.h"
26 
27 using namespace RooFit;
28 
29 void fillWorkspace(RooWorkspace &w);
30 
31 void rf510_wsnamedsets()
32 {
33  // C r e a t e m o d e l a n d d a t a s e t
34  // -----------------------------------------------
35 
36  RooWorkspace *w = new RooWorkspace("w");
37  fillWorkspace(*w);
38 
39  // Exploit convention encoded in named set "parameters" and "observables"
40  // to use workspace contents w/o need for introspected
41  RooAbsPdf *model = w->pdf("model");
42 
43  // Generate data from pdf in given observables
44  RooDataSet *data = model->generate(*w->set("observables"), 1000);
45 
46  // Fit model to data
47  model->fitTo(*data);
48 
49  // Plot fitted model and data on frame of first (only) observable
50  RooPlot *frame = ((RooRealVar *)w->set("observables")->first())->frame();
51  data->plotOn(frame);
52  model->plotOn(frame);
53 
54  // Overlay plot with model with reference parameters as stored in snapshots
55  w->loadSnapshot("reference_fit");
56  model->plotOn(frame, LineColor(kRed));
57  w->loadSnapshot("reference_fit_bkgonly");
58  model->plotOn(frame, LineColor(kRed), LineStyle(kDashed));
59 
60  // Draw the frame on the canvas
61  new TCanvas("rf510_wsnamedsets", "rf503_wsnamedsets", 600, 600);
62  gPad->SetLeftMargin(0.15);
63  frame->GetYaxis()->SetTitleOffset(1.4);
64  frame->Draw();
65 
66  // Print workspace contents
67  w->Print();
68 
69  // Workspace will remain in memory after macro finishes
70  gDirectory->Add(w);
71 }
72 
73 void fillWorkspace(RooWorkspace &w)
74 {
75  // C r e a t e m o d e l
76  // -----------------------
77 
78  // Declare observable x
79  RooRealVar x("x", "x", 0, 10);
80 
81  // Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters
82  RooRealVar mean("mean", "mean of gaussians", 5, 0, 10);
83  RooRealVar sigma1("sigma1", "width of gaussians", 0.5);
84  RooRealVar sigma2("sigma2", "width of gaussians", 1);
85 
86  RooGaussian sig1("sig1", "Signal component 1", x, mean, sigma1);
87  RooGaussian sig2("sig2", "Signal component 2", x, mean, sigma2);
88 
89  // Build Chebychev polynomial pdf
90  RooRealVar a0("a0", "a0", 0.5, 0., 1.);
91  RooRealVar a1("a1", "a1", 0.2, 0., 1.);
92  RooChebychev bkg("bkg", "Background", x, RooArgSet(a0, a1));
93 
94  // Sum the signal components into a composite signal pdf
95  RooRealVar sig1frac("sig1frac", "fraction of component 1 in signal", 0.8, 0., 1.);
96  RooAddPdf sig("sig", "Signal", RooArgList(sig1, sig2), sig1frac);
97 
98  // Sum the composite signal and background
99  RooRealVar bkgfrac("bkgfrac", "fraction of background", 0.5, 0., 1.);
100  RooAddPdf model("model", "g1+g2+a", RooArgList(bkg, sig), bkgfrac);
101 
102  // Import model into pdf
103  w.import(model);
104 
105  // 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
106  // ---------------------------------------------------------------------------------------
107 
108  // Define named sets "parameters" and "observables", which list which variables should be considered
109  // parameters and observables by the users convention
110  //
111  // Variables appearing in sets _must_ live in the workspace already, or the autoImport flag
112  // of defineSet must be set to import them on the fly. Named sets contain only references
113  // to the original variables, therefore the value of observables in named sets already
114  // reflect their 'current' value
115  RooArgSet *params = (RooArgSet *)model.getParameters(x);
116  w.defineSet("parameters", *params);
117  w.defineSet("observables", x);
118 
119  // 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
120  // ---------------------------------------------------------------------------------------------------
121 
122  // Define a parameter 'snapshot' in the pdf
123  // Unlike a named set, a parameter snapshot stores an independent set of values for
124  // a given set of variables in the workspace. The values can be stored and reloaded
125  // into the workspace variable objects using the loadSnapshot() and saveSnapshot()
126  // methods. A snapshot saves the value of each variable, any errors that are stored
127  // with it as well as the 'Constant' flag that is used in fits to determine if a
128  // parameter is kept fixed or not.
129 
130  // Do a dummy fit to a (supposedly) reference dataset here and store the results
131  // of that fit into a snapshot
132  RooDataSet *refData = model.generate(x, 10000);
133  model.fitTo(*refData, PrintLevel(-1));
134 
135  // The kTRUE flag imports the values of the objects in (*params) into the workspace
136  // If not set, the present values of the workspace parameters objects are stored
137  w.saveSnapshot("reference_fit", *params, kTRUE);
138 
139  // Make another fit with the signal component forced to zero
140  // and save those parameters too
141 
142  bkgfrac.setVal(1);
143  bkgfrac.setConstant(kTRUE);
144  bkgfrac.removeError();
145  model.fitTo(*refData, PrintLevel(-1));
146 
147  w.saveSnapshot("reference_fit_bkgonly", *params, kTRUE);
148 }
RooWorkspace.h
RooPlot::Draw
virtual void Draw(Option_t *options=0)
Draw this plot and all of the elements it contains.
Definition: RooPlot.cxx:691
kTRUE
const Bool_t kTRUE
Definition: RtypesCore.h:91
RooChebychev.h
RooAddPdf
RooAddPdf is an efficient implementation of a sum of PDFs of the form.
Definition: RooAddPdf.h:32
RooAbsCollection::first
RooAbsArg * first() const
Definition: RooAbsCollection.h:177
RooFit::PrintLevel
RooCmdArg PrintLevel(Int_t code)
Definition: RooGlobalFunc.cxx:192
RooChebychev
Chebychev polynomial p.d.f.
Definition: RooChebychev.h:25
RooWorkspace::loadSnapshot
Bool_t loadSnapshot(const char *name)
Load the values and attributes of the parameters in the snapshot saved with the given name.
Definition: RooWorkspace.cxx:1208
RooArgList
RooArgList is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgList.h:21
RooGaussian.h
x
Double_t x[n]
Definition: legend1.C:17
RooGaussian
Plain Gaussian p.d.f.
Definition: RooGaussian.h:24
RooAddPdf.h
TCanvas.h
RooWorkspace::set
const RooArgSet * set(const char *name)
Return pointer to previously defined named set with given nmame If no such set is found a null pointe...
Definition: RooWorkspace.cxx:977
RooDataSet.h
TFile.h
RooWorkspace::import
Bool_t import(const RooAbsArg &arg, const RooCmdArg &arg1=RooCmdArg(), const RooCmdArg &arg2=RooCmdArg(), const RooCmdArg &arg3=RooCmdArg(), const RooCmdArg &arg4=RooCmdArg(), const RooCmdArg &arg5=RooCmdArg(), const RooCmdArg &arg6=RooCmdArg(), const RooCmdArg &arg7=RooCmdArg(), const RooCmdArg &arg8=RooCmdArg(), const RooCmdArg &arg9=RooCmdArg())
Import a RooAbsArg object, e.g.
Definition: RooWorkspace.cxx:361
RooWorkspace::Print
void Print(Option_t *opts=0) const
Print contents of the workspace.
Definition: RooWorkspace.cxx:2194
RooFit
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
Definition: RooCFunction1Binding.h:29
RooAbsData::plotOn
virtual RooPlot * plotOn(RooPlot *frame, const RooCmdArg &arg1=RooCmdArg::none(), const RooCmdArg &arg2=RooCmdArg::none(), const RooCmdArg &arg3=RooCmdArg::none(), const RooCmdArg &arg4=RooCmdArg::none(), const RooCmdArg &arg5=RooCmdArg::none(), const RooCmdArg &arg6=RooCmdArg::none(), const RooCmdArg &arg7=RooCmdArg::none(), const RooCmdArg &arg8=RooCmdArg::none()) const
Definition: RooAbsData.cxx:547
RooPlot.h
gDirectory
#define gDirectory
Definition: TDirectory.h:236
RooPlot::GetYaxis
TAxis * GetYaxis() const
Definition: RooPlot.cxx:1258
RooWorkspace::saveSnapshot
Bool_t saveSnapshot(const char *name, const char *paramNames)
Save snapshot of values and attributes (including "Constant") of given parameters.
Definition: RooWorkspace.cxx:1162
RooPlot
A RooPlot is a plot frame and a container for graphics objects within that frame.
Definition: RooPlot.h:44
RooWorkspace::pdf
RooAbsPdf * pdf(const char *name) const
Retrieve p.d.f (RooAbsPdf) with given name. A null pointer is returned if not found.
Definition: RooWorkspace.cxx:1277
RooRealVar.h
kRed
@ kRed
Definition: Rtypes.h:66
RooConstVar.h
RooWorkspace
The RooWorkspace is a persistable container for RooFit projects.
Definition: RooWorkspace.h:43
RooFit::LineColor
RooCmdArg LineColor(Color_t color)
Definition: RooGlobalFunc.cxx:57
TCanvas
The Canvas class.
Definition: TCanvas.h:23
TAxis.h
kDashed
@ kDashed
Definition: TAttLine.h:48
gPad
#define gPad
Definition: TVirtualPad.h:287
RooDataSet
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
make_cnn_model.model
model
Definition: make_cnn_model.py:6
RooAbsPdf
Definition: RooAbsPdf.h:43
RooFit::LineStyle
RooCmdArg LineStyle(Style_t style)
Definition: RooGlobalFunc.cxx:58
TAttAxis::SetTitleOffset
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition: TAttAxis.cxx:293
RooRealVar
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:37
TH1.h
RooArgSet
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:29
RooWorkspace::defineSet
Bool_t defineSet(const char *name, const RooArgSet &aset, Bool_t importMissing=kFALSE)
Define a named RooArgSet with given constituents.
Definition: RooWorkspace.cxx:855