void testv1() {
	int n = 1000001;
	Int_t v1;
	TTree *tree = new TTree("tree", "Just a tree");
	tree->Branch("v1", &v1, "v1/i");
	for (v1 = 0 ; v1 < n ; v1++) tree->Fill();
	tree->Draw("v1", "", "goff");
	Double_t *v1array = tree->GetV1();
	cout << tree->GetSelectedRows() << endl
	     << v1array[999999] << endl
	     << v1array[1000000] << endl;
}