TestNonCentral.C File Reference

Detailed Description

Processing /mnt/build/workspace/root-makedoc-v614/rootspi/rdoc/src/v6-14-00-patches/tutorials/roostats/TestNonCentral.C...

RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby 
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt

[#1] INFO:InputArguments -- RooNonCentralChiSquare sum being forced
[#0] WARNING:Eval -- RooNonCentralChiSquare did not converge: for x=36 k=2.01, lambda=5 fractional error = 0.00108172
 either adjust tolerance with SetErrorTolerance(tol) or max_iter with SetMaxIter(max_it)

using namespace RooFit;
void TestNonCentral(){

   RooWorkspace w("w");
   // k <2, must use sum
   w.factory("NonCentralChiSquare::nc(x[0,50],k[1.99,0,5],lambda[5])");
   // kk > 2 can use bessel
   w.factory("NonCentralChiSquare::ncc(x,kk[2.01,0,5],lambda)");
   // kk > 2, force sum
   w.factory("NonCentralChiSquare::nccc(x,kk,lambda)");
   ((RooNonCentralChiSquare*)w.pdf("nccc"))->SetForceSum(true);

   // a normal "central" chi-square for comparison when lambda->0
   w.factory("ChiSquarePdf::cs(x,k)");

   //w.var("kk")->setVal(4.); // test a large kk

   RooDataSet* ncdata = w.pdf("nc")->generate(*w.var("x"),100);
   RooDataSet* csdata = w.pdf("cs")->generate(*w.var("x"),100);
   RooPlot* plot = w.var("x")->frame();
   ncdata->plotOn(plot,MarkerColor(kRed));
   csdata->plotOn(plot,MarkerColor(kBlue));
   w.pdf("nc")->plotOn(plot,LineColor(kRed));
   w.pdf("ncc")->plotOn(plot,LineColor(kGreen));
   w.pdf("nccc")->plotOn(plot,LineColor(kYellow),LineStyle(kDashed));
   w.pdf("cs")->plotOn(plot,LineColor(kBlue),LineStyle(kDotted));
   plot->Draw();

}

Author

Lorenzo Moneta

Definition in file TestNonCentral.C.