using namespace RooFit;
void pdf_2d()
{

  RooWorkspace work("work",kTRUE) ;

  TMatrixDSym m(2) ; 
  m(0,0) = m(1,1) = 1 ; 
  m(1,0) = m(0,1) = 0.7;

  work.import(m,"cov");
  work.factory("MultiVarGaussian::mvg({x[-5,5],y[-5,5]},{0,0},cov)");
  //work.factory( "PROD::projx(mvg|y{-1})" );
  work.factory( "PROD::projy(mvg|y)" );

  TH2* h = work::mvg.createHistogram("x,y");
  h->SetStats( 0 );
  h->SetTitle( "Two-Dimensional PDF" );
  h->Draw("cont3");

 

  hproj = h->ProjectionX("bla", 30,30 );
  cout << hproj->GetBinCenter( 31 ) << endl;

  hproj->Scale( 1./hproj->Integral() );
  hproj->SetStats(0);
  hproj->SetTitle( "Conditional PDF" );
  hproj->Draw();

  gPad->SaveAs( "conditional_pdf.pdf" );

  return;

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

  // RooPlot* framey = work::y.frame(-1,1);
  // work::mvg.plotOn( framey );
  
  // framey->Draw();


}