@Override
    public float get(int i, int j) {
        return A[index(i, j)];
    }
@Test
    public void testGet() {
        System.out.println("get");
        assertEquals(0.9f, matrix.get(0, 0), 1E-6f);
        assertEquals(0.8f, matrix.get(2, 2), 1E-6f);
        assertEquals(0.5f, matrix.get(1, 1), 1E-6f);
        assertEquals(0.0f, matrix.get(2, 0), 1E-6f);
        assertEquals(0.0f, matrix.get(0, 2), 1E-6f);
        assertEquals(0.4f, matrix.get(0, 1), 1E-6f);
    }