### Question:
PackedRatingData { static int chunk(int idx) { return idx >> CHUNK_SHIFT; } 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 testChunk() { assertThat(chunk(0), equalTo(0)); assertThat(chunk(39), equalTo(0)); assertThat(chunk(4095), equalTo(0)); assertThat(chunk(4096), equalTo(1)); assertThat(chunk(6938), equalTo(1)); assertThat(chunk(1 << 14), equalTo(4)); }