ROOT   Reference Guide
rf509_wsinteractive.py File Reference

## Namespaces

namespace  rf509_wsinteractive

## Detailed Description

Organization and simultaneous fits: easy interactive access to workspace contents - CINT to CLING code migration

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, 0.0, 1.0)
a1 = ROOT.RooRealVar("a1", "a1", -0.2, 0.0, 1.0)
bkg = ROOT.RooChebychev("bkg", "Background", x, [a0, a1])
# Sum the signal components into a composite signal pdf
sig1frac = ROOT.RooRealVar("sig1frac", "fraction of component 1 in signal", 0.8, 0.0, 1.0)
sig = ROOT.RooAddPdf("sig", "Signal", [sig1, sig2], [sig1frac])
# Sum the composite signal and background
bkgfrac = ROOT.RooRealVar("bkgfrac", "fraction of background", 0.5, 0.0, 1.0)
model = ROOT.RooAddPdf("model", "g1+g2+a", [bkg, sig], [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", True)
# 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["model"]
x = w["x"]
d = model.generate({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, Components=bkg, LineStyle="--")
# correct syntax
bkg = w["bkg"]
model.plotOn(frame)
model.plotOn(frame, Components=bkg, LineStyle="--")
# 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")
Date
February 2018

Definition in file rf509_wsinteractive.py.