doc/master/rf206__treevistools_8py.html

import ROOT


# Set up composite pdf

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


# 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)

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)


# 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))


# Build Chebychev polynomial pdf

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

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

bkg1 = ROOT.RooChebychev("bkg1", "Background 1",

                         x, ROOT.RooArgList(a0, a1))


# Build expontential pdf

alpha = ROOT.RooRealVar("alpha", "alpha", -1)

bkg2 = ROOT.RooExponential("bkg2", "Background 2", x, alpha)


# Sum the background components into a composite background pdf

bkg1frac = ROOT.RooRealVar(

    "bkg1frac", "fraction of component 1 in background", 0.2, 0., 1.)

bkg = ROOT.RooAddPdf(

    "bkg", "Signal", ROOT.RooArgList(bkg1, bkg2), ROOT.RooArgList(bkg1frac))


# 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))


# Print composite tree in ASCII

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


# Print tree to stdout

model.Print("t")


# Print tree to file

model.printCompactTree("", "rf206_asciitree.txt")


# Draw composite tree graphically

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


# Print GraphViz DOT file with representation of tree

model.graphVizTree("rf206_model.dot")


# Make graphic output file with one of the GraphViz tools

# (freely available from www.graphviz.org)

#

# 'Top-to-bottom graph'

# unix> dot -Tgif -o rf207_model_dot.gif rf207_model.dot

#

# 'Spring-model graph'

# unix> fdp -Tgif -o rf207_model_fdp.gif rf207_model.dot