@Test
	public void sub_test() {
		
		try{
		double []mat1= {1.0,2.0,3.0,1.0};
		double []mat2= {2.0,1.0,5.0,0.0};
		double result[] = Vector.sub(mat2, mat1);
		double exp[]= {1.0,-1.0,2.0,-1.0};
		Assert.assertArrayEquals(exp, result, 0);
		}		
		catch (Exception e) {
			// TODO Auto-generated catch block
			fail("Not yet implemented");
		}
	}