using namespace RooFit;
void conditional_pdf()
{
  gStyle->SetPalette(1);
  RooWorkspace work("work",kTRUE) ;
  work.factory("expr::func('a0*(x-a1)*(x-a1)+a2',x[-5,5],a0[-0.2],a1[0],a2[3])");
  work.factory("Gaussian::g(y[-5,5],func,sigma[0.5]))");

  // RooPlot* frame = work::x.frame();
  // work::func.plotOn( frame );
  // frame->Draw();

  TH2* h = work::g.createHistogram("x,y");
  //  h->Draw("cont3");
  h->SetStats( 0 );
  h->SetTitle( "Uncorrelated, Not Independent" );
  h->Draw("colz");

  cout << h->GetCorrelationFactor() << endl;
  gPad->SaveAs( "uncorr_not_indep.pdf" );
}