Rf 5 1 1_Wsfactory_Basic

Organization and simultaneous fits: basic use of the 'object factory' associated with a workspace to rapidly build pdfs functions and their parameter components

Author: Clemens Lange, Wouter Verkerke (C++ version)
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Monday, January 17, 2022 at 10:06 AM.

In [ ]:
import ROOT


compact = False
w = ROOT.RooWorkspace("w")

Creating and adding basic pdfs

Remake example pdf of tutorial rs502_wspacewrite.C:

Basic pdf construction: ClassName.ObjectName(constructor arguments) Variable construction : VarName[x,xlo,xhi], VarName[xlo,xhi], VarName[x] P.d.f. addition : SUM.ObjectName(coef1pdf1,...coefMpdfM,pdfN)

In [ ]:
if not compact:
    # Use object factory to build pdf of tutorial rs502_wspacewrite
    w.factory("Gaussian::sig1(x[-10,10],mean[5,0,10],0.5)")
    w.factory("Gaussian::sig2(x,mean,1)")
    w.factory("Chebychev::bkg(x,{a0[0.5,0.,1],a1[-0.2,0.,1.]})")
    w.factory("SUM::sig(sig1frac[0.8,0.,1.]*sig1,sig2)")
    w.factory("SUM::model(bkgfrac[0.5,0.,1.]*bkg,sig)")

else:

    # Use object factory to build pdf of tutorial rs502_wspacewrite but
    #  - Contracted to a single line recursive expression,
    #  - Omitting explicit names for components that are not referred to explicitly later

    w.factory(
        "SUM::model(bkgfrac[0.5,0.,1.]*Chebychev::bkg(x[-10,10],{a0[0.5,0.,1],a1[-0.2,0.,1.]}), "
        "SUM(sig1frac[0.8,0.,1.]*Gaussian(x,mean[5,0,10],0.5), Gaussian(x,mean,1)))"
    )

Advanced pdf constructor arguments

P.d.f. constructor arguments may by any type of ROOT.RooAbsArg, also

Double_t -. converted to ROOT.RooConst(...) {a,b,c} -. converted to ROOT.RooArgSet() or ROOT.RooArgList() depending on required ctor arg dataset name -. convered to ROOT.RooAbsData reference for any dataset residing in the workspace enum -. Any enum label that belongs to an enum defined in the (base) class

Make a dummy dataset pdf 'model' and import it in the workspace

In [ ]:
data = w["model"].generate({w["x"]}, 1000)

Cannot call 'import' directly because this is a python keyword:

In [ ]:
w.Import(data, Rename="data")

Construct a KEYS pdf passing a dataset name and an enum type defining the mirroring strategy w.factory("KeysPdf::k(x,data,NoMirror,0.2)") Workaround for pyROOT

In [ ]:
x = w["x"]
k = ROOT.RooKeysPdf("k", "k", x, data, ROOT.RooKeysPdf.NoMirror, 0.2)
w.Import(k, RenameAllNodes="workspace")

Print workspace contents

In [ ]:
w.Print()