@Test
public void testSparseToString() {

	SparseVector v1 = new SparseVector(8, new int[]{1, 3, 5, 7}, new double[]{2.0, 2.0, 2.0, 2.0});
	Assert.assertEquals(VectorUtil.toString(v1), "$8$1:2.0 3:2.0 5:2.0 7:2.0");
}