Test smeared log IP chi^2 shape

test_smeared_chisq.py

import ROOT
from ROOT import RooFit as RF
ROOT.gROOT.ProcessLine('#include "charmproduction/fitting/shape_classes/RooSmearedLogChiSquared.cxx"')

w = ROOT.RooWorkspace('w')
w.factory('x[-5, 5]')
w.factory('mu_ip[2, -10, 10]')
w.factory('alphaL_ip[1, 0.1, 10]')
w.factory('alphaR_ip[1, 0.1, 10]')
w.factory('RooSmearedLogChiSquared::pdf_ip(x, mu_ip, alphaL_ip, alphaR_ip)')

xset = ROOT.RooArgSet(w.var('x'))
ds = w.pdf('pdf_ip').generate(xset, 10000)
w.pdf('pdf_ip').fitTo(ds)
xframe = w.var('x').frame()
ds.plotOn(xframe)
w.pdf('pdf_ip').plotOn(xframe)
c = ROOT.TCanvas('single_fit', 'single_fit', 400, 400)
xframe.Draw()
c.SaveAs('test_smeared_chisq_single.pdf')

# Generator PDF, fitting PDF, observables, generator options, fitting options
study = ROOT.RooMCStudy(
    w.pdf('pdf_ip'),
    xset,
    RF.Silence(),
    RF.FitOptions(RF.Save(True), RF.PrintEvalErrors(0))
)
study.generateAndFit(1000, 10000)

params = ['mu_ip', 'alphaL_ip', 'alphaR_ip']
nparams = len(params)
c = ROOT.TCanvas('params', 'params', nparams*200, 400)
c.Divide(nparams, 2)
idx = 1
for param in params:
    plot_param = study.plotParam(w.var(param), RF.Bins(40))
    plot_pull = study.plotPull(w.var(param), RF.Bins(40), RF.FitGauss(True))
    c.cd(idx)
    plot_param.Draw()
    c.cd(idx + nparams)
    plot_pull.Draw()
    idx += 1
c.SaveAs('test_smeared_chisq.pdf')