#include<iostream>

#include<TH1D.h>
#include<TROOT.h>
#include<TCanvas.h>
#include<TF1.h>

//**********<<< Lorentzian >>>**********
double Lorentzian(double* x, double* p)
{
	return pow(p[1], 2.) / (pow(x[0] - p[0], 2.) + pow(p[1], 2.));
}

//**********<<< Gaussian >>>**********
double Gaussian(double* x, double* p)
{
	return exp(-log(2.) * pow((x[0] - p[0]) / p[1], 2.));//p[1] is half width at half maximum
}

void test()
{
	if (gROOT->FindObject("h1") != 0) { gROOT->ProcessLine("delete h1"); }
	TH1D* h1 = new TH1D("h1", "h1", 1000, -10, 10);

	if (gROOT->FindObject("h2") != 0) { gROOT->ProcessLine("delete h2"); }
	TH1D* h2 = new TH1D("h2", "h2", 1000, -10, 10);

	if (gROOT->FindObject("h3") != 0) { gROOT->ProcessLine("delete h3"); }
	TH1D* h3 = new TH1D("h3", "h3", 1000, -10, 10);

	TF1* peak = new TF1("peak", Lorentzian, -100, 100, 2);

	peak->SetParameter(0, 0);//center value
	peak->SetParameter(1, 1);//half width at half maximum
	for (int i = 0; i < 10000; i++)
	{
		h1->Fill(peak->GetRandom());
	}

	peak->SetParameter(0, 1);//center value
	peak->SetParameter(1, 1);//half width at half maximum
	for (int i = 0; i < 10000; i++)
	{
		h2->Fill(peak->GetRandom());
	}

	peak->SetParameter(0, 0);//center value
	peak->SetParameter(1, 0.5);//half width at half maximum
	for (int i = 0; i < 10000; i++)
	{
		h3->Fill(peak->GetRandom());
	}
	
	if (gROOT->FindObject("canv1") != 0) { gROOT->ProcessLine("delete canv1"); }
	TCanvas* canv1 = new TCanvas("canv1", "", 0, 0, 1000, 500);
	h1->Draw();
	
	if (gROOT->FindObject("canv2") != 0) { gROOT->ProcessLine("delete canv2"); }
	TCanvas* canv2 = new TCanvas("canv2", "", 32, 62, 1000, 500);
	h2->Draw();
	
	if (gROOT->FindObject("canv3") != 0) { gROOT->ProcessLine("delete canv3"); }
	TCanvas* canv3 = new TCanvas("canv3", "", 58, 93, 1000, 500);
	h3->Draw();
}