ROOT_528-00b_version: tutorials/roostats/TestNonCentral.C Source File

00001 
00002 using namespace RooFit;
00003 TestNonCentral(){
00004 
00005   RooWorkspace w("w");
00006   // k <2, must use sum
00007   w.factory("NonCentralChiSquare::nc(x[0,50],k[1.99,0,5],lambda[5])");
00008   // kk > 2 can use bessel
00009   w.factory("NonCentralChiSquare::ncc(x,kk[2.01,0,5],lambda)");
00010   // kk > 2, force sum
00011   w.factory("NonCentralChiSquare::nccc(x,kk,lambda)");
00012   ((RooNonCentralChiSquare*)w.pdf("nccc"))->SetForceSum(true);
00013 
00014   // a normal "central" chi-square for comparision when lambda->0
00015   w.factory("ChiSquarePdf::cs(x,k)");
00016 
00017   //w.var("kk")->setVal(4.); // test a large kk
00018 
00019   RooDataSet* ncdata = w.pdf("nc")->generate(*w.var("x"),100);
00020   RooDataSet* csdata = w.pdf("cs")->generate(*w.var("x"),100);
00021   RooPlot* plot = w.var("x")->frame();
00022   ncdata->plotOn(plot,MarkerColor(kRed));
00023   csdata->plotOn(plot,MarkerColor(kBlue));
00024   w.pdf("nc")->plotOn(plot,LineColor(kRed));
00025   w.pdf("ncc")->plotOn(plot,LineColor(kGreen));
00026   w.pdf("nccc")->plotOn(plot,LineColor(kYellow),LineStyle(kDashed));
00027   w.pdf("cs")->plotOn(plot,LineColor(kBlue),LineStyle(kDotted));
00028   plot->Draw();
00029   
00030 }