#include "TF2.h"
#include "TF12.h"
#include "TCanvas.h"
#include "TF1.h"

TF2 *f = new TF2("f", "[0]*[0]*(x^2+y^2)+[1]*(x^2+y^2)", -1, 1, -1, 1);
TF12 *sl;
TF1 *sli;

Int_t np = 20;
double *x1=new double[np];
double *w=new double[np];

Double_t slice(Double_t *x, Double_t *par)
{
	f->SetParameters(par[0], par[1]);
	if(sl!=NULL) delete sl;
	sl = new TF12("sl", f, x[0], "y");
	sl->CalcGaussLegendreSamplingPoints(np,x1,w,1e-10);
	return sl->IntegralFast(np, x1, w, -1, 1);
//	return sl->Integral(-1, 1);
}

Double_t intg(Double_t *x, Double_t *par)
{
	if(sli!=NULL) delete sli;
	sli = new TF1("sli", slice, -1, 1, 2);
	sli->SetParameters(x[0], x[1]);

	sli->CalcGaussLegendreSamplingPoints(np,x1,w,1e-10);
	return sli->IntegralFast(np, x1, w, -1, 1);
	
//	return sli->Integral(-1, 1);
}

void par2()
{
	sl=NULL;

	f->SetNpx(100);
	f->SetNpy(100);
	f->SetParameters(2, 1);
	f->Draw("colz");
	
	new TCanvas();
	TF2 *ires = new TF2("ires", intg, -1, 1, -1, 1, 0);
	
	ires->SetNpx(100);
	ires->SetNpy(100);
	
	ires->Draw("colz");
}