Rf 2 0 3_Ranges

Addition and convolution: fitting and plotting in sub ranges

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 Sunday, July 05, 2020 at 08:19 AM.

In [ ]:
from __future__ import print_function
import ROOT

Set up model

Construct observables x

In [ ]:
x = ROOT.RooRealVar("x", "x", -10, 10)

Construct gaussx(x,mx,1)

In [ ]:
mx = ROOT.RooRealVar("mx", "mx", 0, -10, 10)
gx = ROOT.RooGaussian("gx", "gx", x, mx, ROOT.RooFit.RooConst(1))

px = 1 (flat in x)

In [ ]:
px = ROOT.RooPolynomial("px", "px", x)

model = f*gx + (1-f)px

In [ ]:
f = ROOT.RooRealVar("f", "f", 0., 1.)
model = ROOT.RooAddPdf(
    "model", "model", ROOT.RooArgList(gx, px), ROOT.RooArgList(f))

Generated 10000 events in (x,y) from p.d.f. model

In [ ]:
modelData = model.generate(ROOT.RooArgSet(x), 10000)

Fit full range

Fit p.d.f to all data

In [ ]:
r_full = model.fitTo(modelData, ROOT.RooFit.Save(ROOT.kTRUE))

Fit partial range

Define "signal" range in x as [-3,3]

In [ ]:
x.setRange("signal", -3, 3)

Fit p.d.f only to data in "signal" range

In [ ]:
r_sig = model.fitTo(modelData, ROOT.RooFit.Save(
    ROOT.kTRUE), ROOT.RooFit.Range("signal"))

Plot/print results

Make plot frame in x and add data and fitted model

In [ ]:
frame = x.frame(ROOT.RooFit.Title("Fitting a sub range"))
modelData.plotOn(frame)
model.plotOn(
    frame, ROOT.RooFit.Range("Full"), ROOT.RooFit.LineStyle(
        ROOT.kDashed), ROOT.RooFit.LineColor(
            ROOT.kRed)) # Add shape in full ranged dashed
model.plotOn(frame)  # By default only fitted range is shown

Print fit results

In [ ]:
print("result of fit on all data ")
r_full.Print()
print("result of fit in in signal region (note increased error on signal fraction)")
r_sig.Print()

Draw frame on canvas

In [ ]:
c = ROOT.TCanvas("rf203_ranges", "rf203_ranges", 600, 600)
ROOT.gPad.SetLeftMargin(0.15)
frame.GetYaxis().SetTitleOffset(1.4)
frame.Draw()

c.SaveAs("rf203_ranges.png")

Draw all canvases

In [ ]:
from ROOT import gROOT 
gROOT.GetListOfCanvases().Draw()