Multidimensional models: simple uncorrelated multi-dimensional pdfs
pdf = gauss(x,mx,sx) * gauss(y,my,sy)
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 Tuesday, March 19, 2024 at 07:15 PM.
import ROOT
Create two pdfs gaussx(x,meanx,sigmax) gaussy(y,meany,sigmay) and its variables
x = ROOT.RooRealVar("x", "x", -5, 5)
y = ROOT.RooRealVar("y", "y", -5, 5)
meanx = ROOT.RooRealVar("mean1", "mean of gaussian x", 2)
meany = ROOT.RooRealVar("mean2", "mean of gaussian y", -2)
sigmax = ROOT.RooRealVar("sigmax", "width of gaussian x", 1)
sigmay = ROOT.RooRealVar("sigmay", "width of gaussian y", 5)
gaussx = ROOT.RooGaussian("gaussx", "gaussian PDF", x, meanx, sigmax)
gaussy = ROOT.RooGaussian("gaussy", "gaussian PDF", y, meany, sigmay)
[#0] WARNING:InputArguments -- The parameter 'sigmax' with range [-inf, inf] of the RooGaussian 'gaussx' exceeds the safe range of (0, inf). Advise to limit its range. [#0] WARNING:InputArguments -- The parameter 'sigmay' with range [-inf, inf] of the RooGaussian 'gaussy' exceeds the safe range of (0, inf). Advise to limit its range.
Multiply gaussx and gaussy into a two-dimensional pdf gaussxy
gaussxy = ROOT.RooProdPdf("gaussxy", "gaussx*gaussy", [gaussx, gaussy])
Generate 10000 events in x and y from gaussxy
data = gaussxy.generate({x, y}, 10000)
Plot x distribution of data and projection of gaussxy x = Int(dy) gaussxy(x,y)
xframe = x.frame(Title="X projection of gauss(x)*gauss(y)")
data.plotOn(xframe)
gaussxy.plotOn(xframe)
<cppyy.gbl.RooPlot object at 0xa140ea0>
[#1] INFO:Plotting -- RooAbsReal::plotOn(gaussxy) plot on x integrates over variables (y)
Plot x distribution of data and projection of gaussxy y = Int(dx) gaussxy(x,y)
yframe = y.frame(Title="Y projection of gauss(x)*gauss(y)")
data.plotOn(yframe)
gaussxy.plotOn(yframe)
<cppyy.gbl.RooPlot object at 0xa1e6e40>
[#1] INFO:Plotting -- RooAbsReal::plotOn(gaussxy) plot on y integrates over variables (x)
Make canvas and draw ROOT.RooPlots
c = ROOT.TCanvas("rf304_uncorrprod", "rf304_uncorrprod", 800, 400)
c.Divide(2)
c.cd(1)
ROOT.gPad.SetLeftMargin(0.15)
xframe.GetYaxis().SetTitleOffset(1.4)
xframe.Draw()
c.cd(2)
ROOT.gPad.SetLeftMargin(0.15)
yframe.GetYaxis().SetTitleOffset(1.4)
yframe.Draw()
c.SaveAs("rf304_uncorrprod.png")
Info in <TCanvas::Print>: png file rf304_uncorrprod.png has been created
Draw all canvases
from ROOT import gROOT
gROOT.GetListOfCanvases().Draw()