doc/v624/rf509__wsinteractive_8py.html

import ROOT


def fillWorkspace(w):

    # Create pdf and fill workspace

    # --------------------------------------------------------


    # Declare observable x

    x = ROOT.RooRealVar("x", "x", 0, 10)


    # Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and

    # their parameters

    mean = ROOT.RooRealVar("mean", "mean of gaussians", 5, 0, 10)

    sigma1 = ROOT.RooRealVar("sigma1", "width of gaussians", 0.5)

    sigma2 = ROOT.RooRealVar("sigma2", "width of gaussians", 1)


    sig1 = ROOT.RooGaussian("sig1", "Signal component 1", x, mean, sigma1)

    sig2 = ROOT.RooGaussian("sig2", "Signal component 2", x, mean, sigma2)


    # Build Chebychev polynomial pdf

    a0 = ROOT.RooRealVar("a0", "a0", 0.5, 0., 1.)

    a1 = ROOT.RooRealVar("a1", "a1", -0.2, 0., 1.)

    bkg = ROOT.RooChebychev("bkg", "Background", x, ROOT.RooArgList(a0, a1))


    # Sum the signal components into a composite signal pdf

    sig1frac = ROOT.RooRealVar(

        "sig1frac", "fraction of component 1 in signal", 0.8, 0., 1.)

    sig = ROOT.RooAddPdf(

        "sig", "Signal", ROOT.RooArgList(

            sig1, sig2), ROOT.RooArgList(sig1frac))


    # Sum the composite signal and background

    bkgfrac = ROOT.RooRealVar("bkgfrac", "fraction of background", 0.5, 0., 1.)

    model = ROOT.RooAddPdf(

        "model",

        "g1+g2+a",

        ROOT.RooArgList(

            bkg,

            sig),

        ROOT.RooArgList(bkgfrac))


    w.Import(model)


# Create and fill workspace

# ------------------------------------------------


# Create a workspace named 'w'

# With CINT w could exports its contents to

# a same-name C++ namespace in CINT 'namespace w'.

# but self does not work anymore in CLING.

# so self tutorial is an example on how to

# change the code

w = ROOT.RooWorkspace("w", ROOT.kTRUE)


# Fill workspace with pdf and data in a separate function

fillWorkspace(w)


# Print workspace contents

w.Print()


# self does not work anymore with CLING

# use normal workspace functionality


# Use workspace contents

# ----------------------------------------------


# Old syntax to use the name space prefix operator to access the workspace contents

#

#d = w.model.generate(w.x,1000)

#r = w.model.fitTo(*d)


# use normal workspace methods

model = w.pdf("model")

x = w.var("x")


d = model.generate(ROOT.RooArgSet(x), 1000)

r = model.fitTo(d)


# old syntax to access the variable x

# frame = w.x.frame()


frame = x.frame()

d.plotOn(frame)


# OLD syntax to ommit x.

# NB: The 'w.' prefix can be omitted if namespace w is imported in local namespace

# in the usual C++ way

#

# using namespace w

# model.plotOn(frame)

# model.plotOn(frame, ROOT.RooFit.Components(bkg), ROOT.RooFit.LineStyle(ROOT.kDashed))


# correct syntax

bkg = w.pdf("bkg")

model.plotOn(frame)

ras_bkg = ROOT.RooArgSet(bkg)

model.plotOn(frame, ROOT.RooFit.Components(ras_bkg),

             ROOT.RooFit.LineStyle(ROOT.kDashed))


# Draw the frame on the canvas

c = ROOT.TCanvas("rf509_wsinteractive", "rf509_wsinteractive", 600, 600)

ROOT.gPad.SetLeftMargin(0.15)

frame.GetYaxis().SetTitleOffset(1.4)

frame.Draw()


c.SaveAs("rf509_wsinteractive.png")