#include "Minuit2/Minuit2Minimizer.h"
#include "Math/Functor.h"
#include <iostream>
using namespace std;

double RosenBrock(const double *xx )
{
  const Double_t x = xx[0];
  const Double_t y = xx[1];
  const Double_t tmp1 = y-x*x;
  const Double_t tmp2 = 1-x;
  return 100*tmp1*tmp1+tmp2*tmp2;
}

int NumericalMinimization2()
{
   // Choose method upon creation between:
   // kMigrad, kSimplex, kCombined, 
   // kScan, kFumili
   ROOT::Minuit2::Minuit2Minimizer min ( ROOT::Minuit2::kMigrad );

   min.SetMaxFunctionCalls(1000000);
   min.SetMaxIterations(100000);
   min.SetTolerance(0.001);

   ROOT::Math::Functor f(&RosenBrock,2); 
   double step[2] = {0.01,0.01};
   double variable[2] = { -1.,1.2};

   min.SetFunction(f);

   // Set the free variables to be minimized!
   min.SetVariable(0,"x",variable[0], step[0]);
   min.SetVariable(1,"y",variable[1], step[1]);

   min.Minimize(); 

   const double *xs = min.X();
   cout << "Minimum: f(" << xs[0] << "," << xs[1] << "): " 
       << RosenBrock(xs) << endl;

   return 0;
}