void RotateHistogram() {


   auto h1 = new TH2D("h1","Original histogram",50,-5,5, 30, 0, 10);

   auto func = new TF2("func","xygaus");
   func->SetParameters(1, 0, 2, 7, 1);
   h1->FillRandom("func",100000);


   auto ax = h1->GetXaxis();
   auto ay = h1->GetYaxis(); 
   auto h2 = new TH2D("h2","Rotate histogram",  ay->GetNbins(), ay->GetXmin(), ay->GetXmax(), ax->GetNbins(), ax->GetXmin(), ax->GetXmax() );
   for (int i = 0; i < ax->GetNbins() +2; ++i) { 
      for (int j = 0; j < ay->GetNbins() +2; ++j) {
         h2->SetBinContent( j, i, h1->GetBinContent(i,j));
         if (h1->GetSumw2N() > 0) h2->SetBinError( j, i, h1->GetBinError(i,j));
      }
   }
   //h2->ResetStats();

   auto c = new TCanvas();
   c->Divide(1,2);
   c->cd(1);
   h1->Draw("COLZ");
   c->cd(2); 
   h2->Draw("COLZ");

}