#include <TF2.h>
#include <TH2D.h>
#include "TFile.h"

double f1(double *, double *);
double f2(double *, double *);
double f_f1_f2(double *, double*);

TF2 *f_func1 = new TF2("f_func1", f1, -4, 4, -4, 4, 1);
TF2 *f_func2 = new TF2("f_func2", f2, -4, 4, -4, 4, 1);

void GetHist_test()
{
  TFile *file_out = new TFile("Get_Hist_test.root", "Recreate");
  
  f_func1->SetParameter(0, 5);
  f_func1->Draw("surf2");
  TH2D *h_func1 = (TH2D*)f_func1->GetHistogram();
  h_func1->SetName("h_func1");

  f_func2->SetParameter(0, 5);
  f_func2->Draw("surf2");
  TH2D *h_func2 = (TH2D*)f_func2->GetHistogram();
  h_func2->SetName("h_func2");

  TF2 *f_func1_func2 = new TF2("f_func1_func2", f_f1_f2, -4, 4, -4, 4, 2);
  f_func1_func2->SetParameters(5, 5);
  f_func1_func2->Draw("surf2");
  f_func1_func2->SetNpx(500);
  f_func1_func2->SetNpy(500);
  TH2D *h_func1_func2 = (TH2D*)f_func1_func2->GetHistogram();
  
  h_func1->Write();
  h_func2->Write();
  h_func1_func2->Write();
}



double f1(double *x, double *par)
{
  return par[0]*sin(x[0]*x[1]);
}

double f2(double *x, double *par)
{
  return par[0] + x[0]*x[0]*x[1]*x[1];
}

double f_f1_f2(double *x, double *par)
{
  f_func1->SetParameter(0, par[0]);
  f_func2->SetParameter(0, par[1]);
  
  return f_func1->Eval(x[0], x[1])/f_func2->Eval(x[0], x[1]);
}