void example()
{
	TCanvas* canvas = new TCanvas ("canvas") ;
	TGraph *gr = new TGraph("bunch_of_data.txt","%lg %lg %*lg");
	//fancy fit function
	TF1 *f1 = new TF1("f1","[0]*pow(1+x/[1],-1)*pow(1+pow([2],2)*x/[1],-1/2)",0.0002,100);
	f1->SetParameters(0.9,0.01,0.5);
	//f1->FixParameter(2,0.1);
	f1->SetParNames ("Amplitude","#tau_{D}","S");
	gr->Fit("f1","R");
	
	
	gr->SetTitle("");
	gr->GetYaxis()->SetTitle("G");
	gr->GetXaxis()->SetRangeUser(0,1.2);
	gr->GetXaxis()->SetTitle("log(#tau) in ms");
	gStyle->SetOptFit(111);
	canvas->SetLogx();
	gr->GetYaxis()->SetRangeUser(-0.3,3);
	gr->Draw();
	}