void test_GraphConv()
{
   double x[10]={0,1,2,3,4,5,6,7,8,9};
   double y[10];
   for (int i = 0; i < 10; i++) y[i] = std::exp( -x[i]/10 );
   auto g = new TGraph(10,x,y);
   auto f1 = new TF1("f1",[&](double *xx, double *){ return g->Eval(xx[0]); },0,10,0);

   auto f2 = new TF1("f2","gaus");

   auto conv = new TF1Convolution(f1,f2,-5,15,true);
   auto funcConv = new TF1("funcConv",*conv, 0., 10, conv->GetNpar());
   funcConv->SetParameters(1,0,3);   // amplitude, mean and sigma of gaussian
   funcConv->Print("V");

   // need to use drawclone because hraph object will be deleted 
   funcConv->DrawClone();  
}