#include "TH1.h"
#include "TF1.h"
#include "TStopwatch.h"
#include "TMinuit.h"
#include "TVirtualFitter.h"
#include "TCanvas.h"
#include "TF2.h"
#include "TH1F.h"
#include "TCanvas.h"
#include "TH2F.h"
#include "TLegend.h"
#include "math.h"
#include "TSystem.h"
#include "TStyle.h"
#include <iostream>





void RosenbrockCurvedValley(Int_t & /*nPar*/, Double_t * /*grad*/ , Double_t &fval, Double_t *x, Int_t /*iflag */  ) {

  fval = 100*(x[1] - x[0]*x[0])*(x[1] - x[0]*x[0]) + (1 - x[0])*(1 - x[0]);
  return;
}





void DoFit(const char *fitterType="Minuit2",double par1 = 0, double par2 = 0) {

Double_t foundMinimum[2];
Double_t arglist[100];
  arglist[0] = 0;


  // create fitter instance using type fitter
 TVirtualFitter::SetDefaultFitter(fitterType);
 TVirtualFitter * minuit2 = TVirtualFitter::Fitter(0,2);
 arglist[0] = 1;
 // set print level 
 minuit2->ExecuteCommand("SET PRINT",arglist,1); 
 // set initial prameters
 minuit2->SetParameter(0, "x", par1,   0.1, 0,0);
 minuit2->SetParameter(1, "y", par2,   0.1, 0,0);
 // set function to minimize
 minuit2->SetFCN(RosenbrockCurvedValley);
 // minimize
 minuit2->ExecuteCommand("MIGRAD",arglist,0); 
 // get minimum values 
 foundMinimum[0] = minuit2->GetParameter(0); 
 foundMinimum[1] = minuit2->GetParameter(1);

 

 std::cout << " " << fitterType << " :" << " minimum values for " << par1 << "," << par2 << std::endl; 
  std::cout << " par0 = " << foundMinimum[0] << std::endl;
  std::cout << " par1 = " << foundMinimum[1] << std::endl;

}

void testRosenbrockCurvedValley() { 
  DoFit("Minuit2",5,5);
}

#ifndef __CINT__   
int main() { 

  testRosenbrockCurvedValley(); 
}
#endif