doc/master/rf109__chi2residpull_8py.html

import ROOT


# Set up model

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


# Create observables

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


# Create Gaussian

sigma = ROOT.RooRealVar("sigma", "sigma", 3, 0.1, 10)

mean = ROOT.RooRealVar("mean", "mean", 0, -10, 10)

gauss = ROOT.RooGaussian("gauss", "gauss", x, mean, sigma)


# Generate a sample of 1000 events with sigma=3

data = gauss.generate({x}, 10000)


# Change sigma to 3.15

sigma.setVal(3.15)


# Plot data and slightly distorted model

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


# Overlay projection of gauss with sigma=3.15 on data with sigma=3.0

frame1 = x.frame(Title="Data with distorted Gaussian pdf", Bins=40)

data.plotOn(frame1, DataError="SumW2")

gauss.plotOn(frame1)


# Calculate chi^2

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


# Show the chi^2 of the curve w.r.t. the histogram

# If multiple curves or datasets live in the frame you can specify

# the name of the relevant curve and/or dataset in chiSquare()

print("chi^2 = ", frame1.chiSquare())


# Show residual and pull dists

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


# Construct a histogram with the residuals of the data w.r.t. the curve

hresid = frame1.residHist()


# Construct a histogram with the pulls of the data w.r.t the curve

hpull = frame1.pullHist()


# Create a frame to draw the residual distribution and add the

# distribution to the frame

frame2 = x.frame(Title="Residual Distribution")

frame2.addPlotable(hresid, "P")


# Create a frame to draw the pull distribution and add the distribution to

# the frame

frame3 = x.frame(Title="Pull Distribution")

frame3.addPlotable(hpull, "P")


c = ROOT.TCanvas("rf109_chi2residpull", "rf109_chi2residpull", 900, 300)

c.Divide(3)

c.cd(1)

ROOT.gPad.SetLeftMargin(0.15)

frame1.GetYaxis().SetTitleOffset(1.6)

frame1.Draw()

c.cd(2)

ROOT.gPad.SetLeftMargin(0.15)

frame2.GetYaxis().SetTitleOffset(1.6)

frame2.Draw()

c.cd(3)

ROOT.gPad.SetLeftMargin(0.15)

frame3.GetYaxis().SetTitleOffset(1.6)

frame3.Draw()


c.SaveAs("rf109_chi2residpull.png")

TRangeDynCast
ROOT::Detail::TRangeCast< T, true > TRangeDynCast
TRangeDynCast is an adapter class that allows the typed iteration through a TCollection.
Definition TCollection.h:358