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rf312_multirangefit.py
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1## \file
2## \ingroup tutorial_roofit
3## \notebook -nodraw
4## Multidimensional models: performing fits in multiple (disjoint) ranges in one or more dimensions
5##
6## \macro_code
7##
8## \date February 2018
9## \authors Clemens Lange, Wouter Verkerke (C++ version)
10
11import ROOT
12
13
14# Create 2D pdf and data
15# -------------------------------------------
16
17# Define observables x,y
18x = ROOT.RooRealVar("x", "x", -10, 10)
19y = ROOT.RooRealVar("y", "y", -10, 10)
20
21# Construct the signal pdf gauss(x)*gauss(y)
22mx = ROOT.RooRealVar("mx", "mx", 1, -10, 10)
23my = ROOT.RooRealVar("my", "my", 1, -10, 10)
24
25gx = ROOT.RooGaussian("gx", "gx", x, mx, ROOT.RooFit.RooConst(1))
26gy = ROOT.RooGaussian("gy", "gy", y, my, ROOT.RooFit.RooConst(1))
27
28sig = ROOT.RooProdPdf("sig", "sig", gx, gy)
29
30# Construct the background pdf (flat in x,y)
31px = ROOT.RooPolynomial("px", "px", x)
32py = ROOT.RooPolynomial("py", "py", y)
33bkg = ROOT.RooProdPdf("bkg", "bkg", px, py)
34
35# Construct the composite model sig+bkg
36f = ROOT.RooRealVar("f", "f", 0., 1.)
38 "model", "model", ROOT.RooArgList(
39 sig, bkg), ROOT.RooArgList(f))
40
41# Sample 10000 events in (x,y) from the model
42modelData = model.generate(ROOT.RooArgSet(x, y), 10000)
43
44# Define signal and sideband regions
45# -------------------------------------------------------------------
46
47# Construct the SideBand1,SideBand2, regions
48#
49# |
50# +-------------+-----------+
51# | | |
52# | Side | Sig |
53# | Band1 | nal |
54# | | |
55# --+-------------+-----------+--
56# | |
57# | Side |
58# | Band2 |
59# | |
60# +-------------+-----------+
61# |
62
63x.setRange("SB1", -10, +10)
64y.setRange("SB1", -10, 0)
65
66x.setRange("SB2", -10, 0)
67y.setRange("SB2", 0, +10)
68
69x.setRange("SIG", 0, +10)
70y.setRange("SIG", 0, +10)
71
72x.setRange("FULL", -10, +10)
73y.setRange("FULL", -10, +10)
74
75# Perform fits in individual sideband regions
76# -------------------------------------------------------------------------------------
77
78# Perform fit in SideBand1 region (ROOT.RooAddPdf coefficients will be
79# interpreted in full range)
80r_sb1 = model.fitTo(modelData, ROOT.RooFit.Range(
81 "SB1"), ROOT.RooFit.Save())
82
83# Perform fit in SideBand2 region (ROOT.RooAddPdf coefficients will be
84# interpreted in full range)
85r_sb2 = model.fitTo(modelData, ROOT.RooFit.Range(
86 "SB2"), ROOT.RooFit.Save())
87
88# Perform fits in joint sideband regions
89# -----------------------------------------------------------------------------
90
91# Now perform fit to joint 'L-shaped' sideband region 'SB1|SB2'
92# (ROOT.RooAddPdf coefficients will be interpreted in full range)
93r_sb12 = model.fitTo(modelData, ROOT.RooFit.Range(
94 "SB1,SB2"), ROOT.RooFit.Save())
95
96# Print results for comparison
97r_sb1.Print()
98r_sb2.Print()
99r_sb12.Print()