### Question:
PackedRatingData { static int element(int idx) { return idx & CHUNK_MASK; } PackedRatingData(int[][] us, int[][] is, double[][] vs, int size,
                            KeyIndex uidx, KeyIndex iidx); int size(); IndirectEntry getEntry(int index); KeyIndex getUserIndex(); KeyIndex getItemIndex();  }### Answer:
@Test public void testElement() { assertThat(element(0), equalTo(0)); assertThat(element(39), equalTo(39)); assertThat(element(4095), equalTo(4095)); assertThat(element(4096), equalTo(0)); assertThat(element(6938), equalTo(6938 - 4096)); assertThat(element(1 << 14), equalTo(0)); }