def rooFit202():
print ">>> setup model component: gaussian signals and Chebychev polynomial background..."
x = RooRealVar("x", "x", 0, 10)
mean = RooRealVar("mean", "mean of gaussian", 5)
sigma1 = RooRealVar("sigma1", "width of gaussian", 0.5)
sigma2 = RooRealVar("sigma2", "width of gaussian", 1.0)
sig1 = RooGaussian("sig1", "Signal component 1", x, mean, sigma1)
sig2 = RooGaussian("sig2", "Signal component 2", x, mean, sigma2)
a0 = RooRealVar("a0", "a0", 0.5, 0., 1.)
a1 = RooRealVar("a1", "a1", -0.2, 0., 1.)
bkg = RooChebychev("bkg", "Background", x, RooArgList(a0, a1))
# Sum the signal components into a composite signal p.d.f.
sig1frac = RooRealVar("sig1frac", "fraction of component 1 in signal", 0.8,
0., 1.)
sig = RooAddPdf("sig", "Signal", RooArgList(sig1, sig2),
RooArgList(sig1frac))
print ">>>\n>>> METHOD 1"
print ">>> construct extended composite model..."
# Sum the composite signal and background into an extended pdf nsig*sig+nbkg*bkg
nsig = RooRealVar("nsig", "number of signal events", 500, 0., 10000)
nbkg = RooRealVar("nbkg", "number of background events", 500, 0, 10000)
model = RooAddPdf("model", "(g1+g2)+a", RooArgList(bkg, sig),
RooArgList(nbkg, nsig))
print ">>> sample, fit and plot extended model...\n"
# Generate a data sample of expected number events in x from model
# nsig + nbkg = model.expectedEvents()
# NOTE: since the model predicts a specific number events, one can
# omit the requested number of events to be generated
# Introduce Poisson fluctuation with Extended(kTRUE)
data = model.generate(RooArgSet(x), Extended(kTRUE)) # RooDataSet
# Fit model to data, extended ML term automatically included
# NOTE: Composite extended pdfs can only be successfully fit if the extended likelihood
# term -log(Poisson(Nobs,Nexp)) is included in the minimization because they have
# one extra degree of freedom in their parameterization that is constrained by
# this extended term. If a pdf is capable of calculating an extended term (i.e.
# any extended RooAddPdf), the extended term is AUTOMATICALLY included in the
# likelihood calculation. Override this behaviour with Extended():
# Extended(kTRUE) ADD extended likelihood term
# Extended(kFALSE) DO NOT ADD extended likelihood
#model.fitTo(data,Extended(kTRUE))
model.fitTo(data)
print "\n>>> plot data, model and model components..."
# Plot data and PDF overlaid, use expected number of events for pdf projection
# normalization, rather than observed number of events, data.numEntries()
frame1 = x.frame(Title("extended ML fit example")) # RooPlot
data.plotOn(frame1, Binning(30), Name("data"))
model.plotOn(frame1, Normalization(1.0, RooAbsReal.RelativeExpected),
Name("model"))
# Overlay the background components of model
# NOTE: By default, the pdf is normalized to event count of the last dataset added
# to the plot frame. Use "RelativeExpected" to normalize to the expected
# event count of the pdf instead
argset1 = RooArgSet(bkg)
argset2 = RooArgSet(sig1)
argset3 = RooArgSet(sig2)
argset4 = RooArgSet(bkg, sig2)
model.plotOn(frame1, Components(argset1), LineStyle(kDashed),
LineColor(kBlue),
Normalization(1.0, RooAbsReal.RelativeExpected), Name("bkg"))
#model.plotOn(frame1,Components(argset1),LineStyle(kDashed),LineColor(kBlue), Name("bkg2"))
model.plotOn(frame1, Components(argset2), LineStyle(kDotted),
LineColor(kMagenta),
Normalization(1.0, RooAbsReal.RelativeExpected), Name("sig1"))
model.plotOn(frame1, Components(argset3), LineStyle(kDotted),
LineColor(kPink),
Normalization(1.0, RooAbsReal.RelativeExpected), Name("sig2"))
model.plotOn(frame1, Components(argset4), LineStyle(kDashed),
LineColor(kAzure - 4),
Normalization(1.0, RooAbsReal.RelativeExpected),
Name("bkgsig2"))
print "\n>>> structure of composite pdf:"
model.Print("t") # "tree" mode
print "\n>>> parameters:"
params = model.getVariables() # RooArgSet
params.Print("v")
params.Print()
print "\n>>> params.find(\"...\").getVal():"
print ">>> sigma1 = %.2f" % params.find("sigma1").getVal()
print ">>> sigma2 = %.2f" % params.find("sigma2").getVal()
print ">>> nsig = %6.2f, sig1frac = %5.2f" % (
params.find("nsig").getVal(), params.find("sig1frac").getVal())
print ">>> nbkg = %6.2f" % params.find("nbkg").getVal()
print ">>>\n>>> components:"
comps = model.getComponents() # RooArgSet
sig = comps.find("sig") # RooAbsArg
sigVars = sig.getVariables() # RooArgSet
sigVars.Print()
print ">>>\n>>> METHOD 2"
print ">>> construct extended components first..."
# Associated nsig/nbkg as expected number of events with sig/bkg
nsig = RooRealVar("nsig", "number of signal events", 500, 0., 10000)
nbkg = RooRealVar("nbkg", "number of background events", 500, 0, 10000)
esig = RooExtendPdf("esig", "extended signal pdf", sig, nsig)
ebkg = RooExtendPdf("ebkg", "extended background pdf", bkg, nbkg)
print ">>> sum extended components without coefficients..."
# Construct sum of two extended p.d.f. (no coefficients required)
model2 = RooAddPdf("model2", "(g1+g2)+a", RooArgList(ebkg, esig))
# METHOD 2 is functionally completely equivalent to METHOD 1.
# Its advantage is that the yield parameter is associated to the shape pdf
# directly, while in METHOD 1 the association is made after constructing
# a RooAddPdf. Also, class RooExtendPdf offers extra functionality to
# interpret event counts in a different range.
print ">>> plot model..."
model2.plotOn(frame1, LineStyle(kDashed), LineColor(kRed),
Normalization(1.0, RooAbsReal.RelativeExpected),
Name("model2"))
print ">>> draw on canvas..."
canvas = TCanvas("canvas", "canvas", 100, 100, 800, 600)
legend = TLegend(0.2, 0.85, 0.4, 0.65)
legend.SetTextSize(0.032)
legend.SetBorderSize(0)
legend.SetFillStyle(0)
gPad.SetLeftMargin(0.14)
gPad.SetRightMargin(0.02)
frame1.GetYaxis().SetLabelOffset(0.008)
frame1.GetYaxis().SetTitleOffset(1.4)
frame1.GetYaxis().SetTitleSize(0.045)
frame1.GetXaxis().SetTitleSize(0.045)
frame1.Draw()
legend.AddEntry("data", "data", 'LEP')
legend.AddEntry("model", "composite model", 'L')
legend.AddEntry("model2", "composite model (method 2)", 'L')
legend.AddEntry("bkg", "background only", 'L')
#legend.AddEntry("bkg2", "background only (no extended norm)", 'L')
legend.AddEntry("sig1", "signal 1", 'L')
legend.AddEntry("sig2", "signal 2", 'L')
legend.AddEntry("bkgsig2", "background + signal 2", 'L')
legend.Draw()
canvas.SaveAs("rooFit202.png")
def rooFit207():
print ">>> setup model signal components: gaussians..."
x = RooRealVar("x","x",0,10)
mean = RooRealVar("mean","mean of gaussians",5)
sigma = RooRealVar("sigma","width of gaussians",0.5)
sig = RooGaussian("sig","Signal",x,mean,sigma)
print ">>> setup model background components: Chebychev polynomial plus exponential..."
a0 = RooRealVar("a0","a0",0.5,0.,1.)
a1 = RooRealVar("a1","a1",-0.2,0.,1.)
bkg1 = RooChebychev("bkg1","Background 1",x,RooArgList(a0,a1))
alpha = RooRealVar("alpha","alpha",-1)
bkg2 = RooExponential("bkg2","Background 2",x,alpha)
bkg1frac = RooRealVar("bkg1frac","fraction of component 1 in background",0.2,0.,1.)
bkg = RooAddPdf("bkg","Signal",RooArgList(bkg1,bkg2),RooArgList(bkg1frac))
print ">>> sum signal and background component..."
bkgfrac = RooRealVar("bkgfrac","fraction of background",0.5,0.,1.)
model = RooAddPdf("model","g1+g2+a",RooArgList(bkg,sig),RooArgList(bkgfrac))
# Create dummy dataset that has more observables than the above pdf
y = RooRealVar("y","y",-10,10)
data = RooDataSet("data","data",RooArgSet(x,y))
# Basic information requests:"
print ">>> get list of observables of pdf in context of a dataset..."
# Observables are define each context as the variables
# shared between a model and a dataset. In this case
# that is the variable 'x'
model_obs = model.getObservables(data) # RooArgSet
model_obs.Print('v')
print "\n>>> get list of parameters..."
# Get list of parameters, given list of observables
model_params = model.getParameters(RooArgSet(x)) # RooArgSet
print ">>> model_params.getStringValue(\"a0\") = %s" % (model_params.getStringValue("a0"))
print ">>> model_params.getRealValue(\"a0\") = %s" % (model_params.getRealValue("a0"))
print ">>> model_params.find(\"a0\").GetName() = %s" % (model_params.find("a0").GetName())
print ">>> model_params.find(\"a0\").getVal() = %s" % (model_params.find("a0").getVal())
# print ">>> for param in model_params:"
# for param in model_params.():
# print ">>> %s"%(model_params.first())
# print ">>> %s"%(model_params.first())
# model_params.selectByName("a*").Print('v')
model_params.Print('v')
print "\n>>> get list of parameters of a dataset..."
# Gives identical results to operation above
model_params2 = model.getParameters(data) # RooArgSet
model_params2.Print()
print "\n>>> get list of components..."
# Get list of component objects, including top-level node
model_comps = model.getComponents() # RooArgSet
model_comps.Print('v')
print "\n>>> modifications to structure of composites..."
sigma2 = RooRealVar("sigma2","width of gaussians",1)
sig2 = RooGaussian("sig2","Signal component 1",x,mean,sigma2)
sig1frac = RooRealVar("sig1frac","fraction of component 1 in signal",0.8,0.,1.)
sigsum = RooAddPdf("sigsum","sig+sig2",RooArgList(sig,sig2),RooArgList(sig1frac))
print ">>> construct a customizer utility to customize model..."
cust = RooCustomizer(model,"cust")
print ">>> instruct the customizer to replace node 'sig' with node 'sigsum'..."
cust.replaceArg(sig,sigsum)
# Build a clone of the input pdf according to the above customization
# instructions. Each node that requires modified is clone so that the
# original pdf remained untouched. The name of each cloned node is that
# of the original node suffixed by the name of the customizer object
#
# The returned head node own all nodes that were cloned as part of
# the build process so when cust_clone is deleted so will all other
# nodes that were created in the process.
cust_clone = cust.build(kTRUE) # RooAbsPdf
# Print structure of clone of model with sig->sigsum replacement.
cust_clone.Print("t")
# delete clone
del cust_clone
def rooFit201():
print ">>> setup model component: gaussian signals and Chebychev polynomial background..."
x = RooRealVar("x","x",0,11)
mean = RooRealVar("mean","mean of gaussians",5)
sigma1 = RooRealVar("sigma1","width of gaussians",0.5)
sigma2 = RooRealVar("sigma2","width of gaussians",1)
sig1 = RooGaussian("sig1","Signal component 1",x,mean,sigma1)
sig2 = RooGaussian("sig2","Signal component 2",x,mean,sigma2)
a0 = RooRealVar("a0","a0",0.5,0.,1.)
a1 = RooRealVar("a1","a1",-0.2,0.,1.)
bkg = RooChebychev("bkg","Background",x,RooArgList(a0,a1))
print ">>>\n>>> METHOD 1 - Two RooAddPdfs"
print ">>> add signal components..."
# Sum the signal components into a composite signal p.d.f.
sig1frac = RooRealVar("sig1frac","fraction of component 1 in signal",0.8,0.,1.)
sig = RooAddPdf("sig","Signal",RooArgList(sig1,sig2),RooArgList(sig1frac))
print ">>> add signal and background..."
# Sum the composite signal and background
bkgfrac = RooRealVar("bkgfrac","fraction of background",0.5,0.,1.)
model = RooAddPdf("model","g1+g2+a",RooArgList(bkg,sig),RooArgList(bkgfrac))
print ">>> sample, fit and plot model..."
data = model.generate(RooArgSet(x),1000) # RooDataSet
model.fitTo(data)
frame1 = x.frame(Title("Example of composite pdf=(sig1+sig2)+bkg")) # RooPlot
data.plotOn(frame1,Binning(50),Name("data"))
model.plotOn(frame1,Name("model"))
# Overlay the background component of model with a dashed line
argset1 = RooArgSet(bkg)
model.plotOn(frame1,Components(argset1),LineWidth(2),Name("bkg")) #,LineStyle(kDashed)
# Overlay the background+sig2 components of model with a dotted line
argset2 = RooArgSet(bkg,sig2)
model.plotOn(frame1,Components(argset2),LineWidth(2),LineStyle(kDashed),LineColor(kAzure-4),Name("bkgsig2")) #,LineStyle(kDotted)
print "\n>>> structure of composite pdf:"
model.Print("t") # "tree" mode
print "\n>>> parameters:"
params = model.getVariables() # RooArgSet
params.Print("v")
params.Print()
print "\n>>> params.find(\"...\").getVal():"
print ">>> sigma1 = %.2f" % params.find("sigma1").getVal()
print ">>> sigma2 = %.2f" % params.find("sigma2").getVal()
print ">>> bkgfrac = %5.2f" % params.find("bkgfrac").getVal()
print ">>> sig1frac = %5.2f" % params.find("sig1frac").getVal()
print ">>>\n>>> components:"
comps = model.getComponents() # RooArgSet
sig = comps.find("sig") # RooAbsArg
sigVars = sig.getVariables() # RooArgSet
sigVars.Print()
print ">>>\n>>> METHOD 2 - One RooAddPdf with recursive fractions"
# Construct sum of models on one go using recursive fraction interpretations
# model2 = bkg + (sig1 + sig2)
model2 = RooAddPdf("model","g1+g2+a",RooArgList(bkg,sig1,sig2),RooArgList(bkgfrac,sig1frac),kTRUE)
# NB: Each coefficient is interpreted as the fraction of the
# left-hand component of the i-th recursive sum, i.e.
# sum4 = A + ( B + ( C + D ) )
# with fraction fA, fB and fC expands to
# sum4 = fA*A + (1-fA)*(fB*B + (1-fB)*(fC*C + (1-fC)*D))
print ">>> plot recursive addition model..."
argset3 = RooArgSet(bkg,sig2)
model2.plotOn(frame1,LineColor(kRed),LineStyle(kDashDotted),LineWidth(3),Name("model2"))
model2.plotOn(frame1,Components(argset3),LineColor(kMagenta),LineStyle(kDashDotted),LineWidth(3),Name("bkgsig22"))
model2.Print("t")
print ">>> draw pdfs and fits on canvas..."
canvas = TCanvas("canvas","canvas",100,100,800,600)
legend = TLegend(0.57,0.87,0.95,0.65)
legend.SetTextSize(0.030)
legend.SetBorderSize(0)
legend.SetFillStyle(0)
gPad.SetLeftMargin(0.14); gPad.SetRightMargin(0.02)
frame1.GetYaxis().SetLabelOffset(0.008)
frame1.GetYaxis().SetTitleOffset(1.4)
frame1.GetYaxis().SetTitleSize(0.045)
frame1.GetXaxis().SetTitleSize(0.045)
frame1.Draw()
legend.AddEntry("data", "data", 'LEP')
legend.AddEntry("model", "composite model", 'L')
legend.AddEntry("model2", "composite model (method 2)", 'L')
legend.AddEntry("bkg", "background only", 'L')
legend.AddEntry("bkgsig2", "background + signal 2", 'L')
legend.AddEntry("bkgsig22","background + signal 2 (method 2)",'L')
legend.Draw()
canvas.SaveAs("rooFit201.png")