float inputFormular(float x0, float x1, float x2) {
	float p0 = 0;
	float p1 = 1;
	float p2 = 2;
	float p3 = 3;
	float p4 = 4;
	float p5 = 5;
	float p6 = 6;
	float p7 = 7;
	float p8 = 8;
	
	
	
	
	
	return p0 +x0*p1 + x1*p2 + x2*p3 + x0*x0*p4 + x1*x1*p5 + x0*x1*p6 + x1*x2*p7 + x0*x2*p8;
	
	
	//1 ++ x[0] ++ x[1] ++ x[2] ++ x[0]*x[0] ++ x[1]*x[1] ++ x[0]*x[1] ++ x[1]*x[2] ++ x[0]*x[2]

}

float GetError(TF1 *f, Double_t x) {
	
	
	float error = sqrt(
		std::pow(f->GetParError(0),2) + std::pow(f->GetParError(1)*x,2) + std::pow(f->GetParError(3)*x*x,2)
		);
	return error ;
}

int fitTest() {
	
	
	TGraph *gr = new TGraph();
	auto rng = new TRandom();
	float sigm = 1000;
	for (int i = 0; i < 100; i++) {
		gr->SetPoint(gr->GetN(),10, inputFormular(10,10,1)+ rng->Gaus(0,sigm));
		gr->SetPoint(gr->GetN(),20,inputFormular(20,10,1)+ rng->Gaus(0,sigm));
		gr->SetPoint(gr->GetN(),30,inputFormular(30,10,1)+ rng->Gaus(0,sigm));
	}
	
	
	TF1 *f = new TF1("f","pol2",0,100);
	gr->Draw("a*");
	gr->Fit("f");
	
	TGraph *gul = new TGraph();
	TGraph *gll = new TGraph();
	for (int i = 0; i < 10; i++) {
		float pt = 5+i*3;
		gul->SetPoint(gul->GetN(),pt, f->Eval(pt) + GetError(f,pt));
		gll->SetPoint(gll->GetN(),pt,f->Eval(pt)- GetError(f,pt));
	}
	gul->Draw("l");
	gll->Draw("l");
	
	std::cout << "Error at 20 is " << GetError(f,20) << std::endl;;

return 0;
}