def rooFit110():
print ">>> setup model..."
x = RooRealVar("x","x",-10,10)
mean = RooConst(-2)
sigma = RooConst(3)
gauss = RooGaussian("gauss","gauss",x,mean,sigma)
frame1 = x.frame(Title("Gaussian pdf")) # RooPlot
gauss.plotOn(frame1)
print ">>> retrieve raw & normalized values of RooFit pdfs...\n>>>"
# Return 'raw' unnormalized value of gauss
print ">>> raw value: gauss.getVal( ) = %.3f" % gauss.getVal() + " depends on x range"
print ">>> normalization: gauss.getVal(x) = %.3f" % gauss.getVal(RooArgSet(x))
print ">>> normalization: gauss.getNorm(x) = %.3f" % gauss.getNorm(RooArgSet(x))
print ">>> 1/(sigma*sqrt(2*pi)) = %.3f" % (1/(sigma.getValV()*sqrt(2*pi)))
# Create object representing integral over gauss
# which is used to calculate gauss_Norm[x] == gauss / gauss_Int[x]
igauss = gauss.createIntegral(RooArgSet(x)) # RooAbsReal
print ">>> integral: igauss.getVal( ) = %.3f" % igauss.getVal()
print ">>> igauss.getVal(x) = %.3f" % igauss.getVal(RooArgSet(x))
print ">>> 1/igauss.getVal(x) = %.3f" % (1/igauss.getVal(RooArgSet(x)))
print ">>> gauss.getVal()/igauss.getVal(x) = %.3f" % (gauss.getVal()/igauss.getVal(RooArgSet(x)))
# maximum
print ">>> maximum: gauss.getMaxVal(x) = %.3f" % gauss.getMaxVal(RooArgSet(x))
print ">>> gauss.getMax(0) = %.3f" % gauss.maxVal(0)
print ">>> gauss.getMax(1) = %.3f" % gauss.maxVal(1)
print ">>> gauss.asTF(x).GetMaximumX() = %.3f" % gauss.asTF(RooArgList(x)).GetMaximumX()
print ">>> gauss.asTF(x).GetMaximum() = %.3f" % gauss.asTF(RooArgList(x)).GetMaximum()
xmaxVal = gauss.asTF(RooArgList(x)).GetMaximumX()
xmax = RooRealVar("x_max","x_max",xmaxVal)
x.setVal(xmaxVal)
print ">>> gauss.getVal( ) = %.3f" % gauss.getVal()
print ">>> gauss.getVal(xmax) = %.3f" % gauss.getVal(RooArgSet(x))
print ">>> gauss.getVal(xmax) = %.3f" % gauss.getVal(RooArgSet(xmax))
print ">>> plot"
frame2 = x.frame(Title("integral of Gaussian pdf")) # RooPlot
line1 = RooLinearVar("line1","line1",x,RooConst(0),RooConst(gauss.getVal()))
line2 = RooLinearVar("line2","line2",x,RooConst(0),RooConst(gauss.getVal(RooArgSet(x))))
igauss.plotOn(frame2,LineColor(kBlue), Name(igauss.GetName()))
line1.plotOn( frame2,LineColor(kRed), Name(line1.GetName()))
line2.plotOn( frame2,LineColor(kGreen),Name(line2.GetName()))
print ">>>\n>>> integrate normalized pdf over subrange..."
# Define a range named "signal" in x from -5,5
x.setRange("signal",-5,5)
# Create an integral of gauss_Norm[x] over x in range "signal"
# This is the fraction of of p.d.f. gauss_Norm[x] which is in
# the range named "signal"
igauss_sig = gauss.createIntegral(RooArgSet(x),NormSet(RooArgSet(x)),Range("signal")) # RooAbsReal
print ">>> gauss_Int[x|signal]_Norm[x] = %.2f" % igauss_sig.getVal()
print ">>> construct cumulative distribution function from pdf..."
# Create the cumulative distribution function of
# gauss, i.e. calculate Int[-10,x] gauss(x') dx'
gauss_cdf = gauss.createCdf(RooArgSet(x)) # RooAbsReal
frame3 = x.frame(Title("cdf of Gaussian pdf")) # RooPlot
gauss_cdf.plotOn(frame3)
print ">>> draw functions on canvas..."
canvas = TCanvas("canvas","canvas",100,100,2000,400)
legend = TLegend(0.6,0.6,0.8,0.42)
legend.SetTextSize(0.032)
legend.SetBorderSize(0)
legend.SetFillStyle(0)
canvas.Divide(3)
for i, frame in enumerate([frame1,frame2,frame3],1):
canvas.cd(i)
gPad.SetLeftMargin(0.14); gPad.SetRightMargin(0.04)
frame.GetYaxis().SetTitleOffset(1.6)
frame.GetYaxis().SetLabelOffset(0.010)
frame.GetYaxis().SetTitleSize(0.045)
frame.GetYaxis().SetLabelSize(0.042)
frame.GetXaxis().SetTitleSize(0.045)
frame.GetXaxis().SetLabelSize(0.042)
frame.Draw()
if i is 2:
legend.AddEntry(line1.GetName(), " gauss.getVal( )",'L')
legend.AddEntry(line2.GetName(), " gauss.getVal(x)",'L')
legend.AddEntry(igauss.GetName(),"igauss.getVal( )",'L')
legend.Draw()
canvas.SaveAs("rooFit110.png")
