#include "TMinuit.h"

void trial_fit(){
	TVirtualFitter::SetDefaultFitter("Minuit");
	double x[10];
	double y[10];
	double ey[10];
	
	TCanvas* c1 = new TCanvas();
	TRandom3* r = new TRandom3();
/*
	for (int i=0; i<10;i++){
		x[i]=i;
		y[i]=r->Poisson(12*i);
		ey[i]=TMath::Sqrt(y[i]);
	}



	TGraphErrors* gr = new TGraphErrors(10,x,y,0,ey);
	gr->Fit("pol1");
	gr->Draw();
	c1->Update();
*/
	TH1D* h1 = new TH1D("h1","h1",10,0,10);
	for (int i=0; i<10;i++){
		h1->Fill(i,r->Poisson(12*i));
	}
	h1->Sumw2();
//	h1->Draw();
	h1->Fit("pol1");
	c1->Update();
	

	TCanvas* c2 = new TCanvas();
	//gMinuit->SetErrorDef(9);
	TGraph *gr1 = (TGraph*)gMinuit->Contour(40,0,1);
	gr1->Draw("alp");
	//gMinuit->SetErrorDef(4);
	//TGraph *gr2 = (TGraph*)gMinuit->Contour(80,0,1);
	//gr2->Draw("lp");
	//gMinuit->SetErrorDef(1);
	//TGraph *gr3 = (TGraph*)gMinuit->Contour(120,0,1);
	//gr3->Draw("lp");
	}