    @Test
    public void testPlusTo() {

        final Matrix a = Matrix.array(new double[]{
                1, 2, 3, 4, 5, 6
        }, 3);

        final Matrix b = Matrix.array(new double[]{
                6, 5, 4, 3, 2, 1
        }, 3);

        final Matrix c = a.plusTo(b);

        assertSame(c, a);
        assertArrayEquals(a.getArray(), new double[]{
                7, 7, 7, 7, 7, 7
        }, 0);
    }