extern "C" void GraphFitChisquareNoEX(Int_t &npar, Double_t *gin, Double_t &f,
			   Double_t *u, Int_t flag);

void testfiti()
{
  TGraph *graph;
  Float_t x[30],y[30],dx[30],dy[30];
  int i;
  for(i=0;i<30;i++){x[i]=i*.5;y[i]=3*x[i]*x[i]*+x[i]-3;dx[i]=0.1;dy[i]=0.01*y[i];}
  graph=new TGraphErrors(30,x,y,dx,dy);
  TVirtualFitter *grFitter=TVirtualFitter::Fitter(graph);
  //grFitter->SetFCN(GraphFitChisquareNoEX);
  grFitter->SetFCN((void (*fcn)(Int_t &, Double_t *, Double_t &f, Double_t *, Int_t))GraphFitChisquareNoEX);
  graph->Fit("pol3","U");
}