qwt 0.4.0

Rust implementation of Quad Wavelet Tree
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315

use rand::Rng;

use crate::{
    perf_and_test_utils::{gen_sequence, TimingQueries},
    AccessUnsigned, HuffQWaveletTree, OccsRangeUnsigned, RSQVector512, RankUnsigned,
    SelectUnsigned, HQWT256,
};

#[test]
fn test_small() {
    let data: [u8; 9] = [1, 0, 1, 0, 3, 4, 5, 3, 7];
    let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut data.clone());

    assert_eq!(qwt.rank(1, 4), Some(2));
    assert_eq!(qwt.rank(1, 0), Some(0));
    assert_eq!(qwt.rank(8, 1), None); // too large symbol
    assert_eq!(qwt.rank(1, 9), Some(2));
    assert_eq!(qwt.rank(7, 9), Some(1));
    assert_eq!(qwt.rank(1, 10), None); // too large position
    assert_eq!(qwt.select(5, 0), Some(6));

    for (i, &v) in data.iter().enumerate() {
        let rank = qwt.rank(v, i).unwrap();
        let s = qwt.select(v, rank).unwrap();
        assert_eq!(s, i);
    }

    // test iterators
    assert!(qwt.iter().eq(data.iter().copied()));
    assert!(qwt.into_iter().eq(data.iter().copied()));

    // test from_iterator
    let qwt: HQWT256<_> = (0..10_u32).cycle().take(1000).collect();

    assert_eq!(qwt.len(), 1000);
}

#[test]
fn test_occs_range() {
    let data: [u8; 9] = [1, 0, 1, 0, 3, 4, 5, 3, 7];
    let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut data.clone());

    // out-of-bounds ranges
    assert!(qwt.occs_range(..data.len() + 1).is_none());
    assert!(qwt.occs_range(data.len() - 1..data.len() + 1).is_none());

    // nonsense ranges
    assert!(qwt.occs_range(5..4).is_none());
    assert!(qwt.occs_range(2..0).is_none());

    // empty ranges
    assert_eq!(0, qwt.occs_range(data.len()..).unwrap().count());
    assert_eq!(0, qwt.occs_range(..0).unwrap().count());

    // unbounded
    let mut occs: Vec<_> = qwt.occs_range(..).unwrap().collect();
    occs.sort_by_key(|p| p.0);
    assert_eq!(occs, [(0, 2), (1, 2), (3, 2), (4, 1), (5, 1), (7, 1)]);

    // start bound
    let mut occs: Vec<_> = qwt.occs_range(3..).unwrap().collect();
    occs.sort_by_key(|p| p.0);
    assert_eq!(occs, [(0, 1), (3, 2), (4, 1), (5, 1), (7, 1)]);

    // end bound
    let mut occs: Vec<_> = qwt.occs_range(..5).unwrap().collect();
    occs.sort_by_key(|p| p.0);
    assert_eq!(occs, [(0, 2), (1, 2), (3, 1)]);

    // fully bounded
    let mut occs: Vec<_> = qwt.occs_range(4..7).unwrap().collect();
    occs.sort_by_key(|p| p.0);
    assert_eq!(occs, [(3, 1), (4, 1), (5, 1)]);

    // empty data
    let data: [u8; 0] = [];
    let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut data.clone());
    assert_eq!(0, qwt.occs_range(..).unwrap().count());
}

/// Property-based test for occs_range on HuffQWaveletTree:
/// 1. sum of all occurrences == range length
/// 2. each symbol's count == rank(symbol, end) - rank(symbol, start)
#[test]
fn test_occs_range_properties() {
    let mut rng = rand::thread_rng();

    for sigma in [4, 16, 64, 256] {
        let sequence = gen_sequence(1000, sigma);
        let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut sequence.clone());
        let n = sequence.len();

        // Test multiple random ranges
        for _ in 0..100 {
            let a = rng.gen_range(0..=n);
            let b = rng.gen_range(0..=n);
            let (start, end) = if a <= b { (a, b) } else { (b, a) };

            let occs: Vec<_> = qwt.occs_range(start..end).unwrap().collect();

            // Property 1: sum of occurrences == range length
            let total: usize = occs.iter().map(|(_, count)| count).sum();
            assert_eq!(
                total,
                end - start,
                "Sum of occurrences should equal range length for range {}..{}",
                start,
                end
            );

            // Property 2: each count matches rank difference
            for (symbol, count) in &occs {
                let rank_end = qwt.rank(*symbol, end).unwrap();
                let rank_start = qwt.rank(*symbol, start).unwrap();
                assert_eq!(
                    *count,
                    rank_end - rank_start,
                    "Count mismatch for symbol {} in range {}..{}",
                    symbol,
                    start,
                    end
                );
            }

            // Property 3: symbols not in occs should have zero count
            for s in 0..sigma {
                let s = s as u8;
                let rank_end = qwt.rank(s, end).unwrap_or(0);
                let rank_start = qwt.rank(s, start).unwrap_or(0);
                let expected_count = rank_end - rank_start;

                let found_count = occs
                    .iter()
                    .find(|(sym, _)| *sym == s)
                    .map(|(_, c)| *c)
                    .unwrap_or(0);

                assert_eq!(
                    found_count, expected_count,
                    "Symbol {} should have count {} but found {} in range {}..{}",
                    s, expected_count, found_count, start, end
                );
            }
        }
    }
}

/// Test occs_range with large alphabets (σ > 256)
/// Uses u16 symbols to support larger alphabet sizes
#[test]
fn test_occs_range_large_alphabet() {
    let mut rng = rand::thread_rng();

    for sigma in [512_u16, 1000, 4000, 16000] {
        // Generate random sequence with u16 symbols
        let sequence: Vec<u16> = (0..2000).map(|_| rng.gen_range(0..sigma)).collect();
        let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut sequence.clone());
        let n = sequence.len();

        // Test multiple random ranges
        for _ in 0..50 {
            let a = rng.gen_range(0..=n);
            let b = rng.gen_range(0..=n);
            let (start, end) = if a <= b { (a, b) } else { (b, a) };

            let occs: Vec<_> = qwt.occs_range(start..end).unwrap().collect();

            // Property 1: sum of occurrences == range length
            let total: usize = occs.iter().map(|(_, count)| count).sum();
            assert_eq!(
                total,
                end - start,
                "σ={}: Sum of occurrences should equal range length for range {}..{}",
                sigma,
                start,
                end
            );

            // Property 2: each count matches rank difference
            for (symbol, count) in &occs {
                let rank_end = qwt.rank(*symbol, end).unwrap();
                let rank_start = qwt.rank(*symbol, start).unwrap();
                assert_eq!(
                    *count,
                    rank_end - rank_start,
                    "σ={}: Count mismatch for symbol {} in range {}..{}",
                    sigma,
                    symbol,
                    start,
                    end
                );
            }

            // Note: HuffQWaveletTree does NOT guarantee lexicographic order
            // (Huffman codes produce a different traversal order)
        }
    }
}

#[test]
fn test_from_iterator() {
    let qwt: HQWT256<_> = (0..10u32).cycle().take(100).collect();

    assert!(qwt.into_iter().eq((0..10u32).cycle().take(100)));
}

#[test]
fn test() {
    const N: usize = 1025;
    for sigma in [4, 5, 7, 8, 9, 15, 16, 17, 31, 32, 33, 255] {
        let mut sequence: [u8; N] = [0; N];
        sequence[N - 1] = sigma - 1;
        let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut sequence.clone());

        for i in 0..N - 1 {
            assert_eq!(qwt.rank(0, i).unwrap(), i);
        }

        for (i, &symbol) in sequence.iter().enumerate() {
            let rank = qwt.rank(symbol, i).unwrap();
            let s = qwt.select(symbol, rank).unwrap();
            assert_eq!(s, i);
        }

        // Select out of bound
        assert_eq!(qwt.select(0, N), None);
        assert_eq!(qwt.select(1, 1), None);
        assert_eq!(qwt.select(sigma - 1, 2), None);
    }

    for sigma in [4, 5, 7, 8, 9, 15, 16, 17, 31, 32, 33, 255, 256, 16000] {
        let mut sequence: [u16; N] = [0; N];
        sequence[N - 1] = sigma - 1;
        let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut sequence.clone());

        for i in 1..N - 1 {
            assert_eq!(qwt.rank(0, i).unwrap(), i);
        }

        for (i, &symbol) in sequence.iter().enumerate() {
            let rank = qwt.rank(symbol, i).unwrap();
            let s = qwt.select(symbol, rank).unwrap();
            assert_eq!(s, i);
        }

        // Select out of bound
        assert_eq!(qwt.select(0, N), None);
        assert_eq!(qwt.select(1, 1), None);
        assert_eq!(qwt.select(sigma - 1, 2), None);
    }
}

#[test]
fn test_get() {
    let n = 1025;
    for sigma in [4, 5, 7, 8, 9, 15, 16, 17, 31, 32, 33, 255, 256] {
        let sequence = gen_sequence(n, sigma);
        let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut sequence.clone());
        for (i, &symbol) in sequence.iter().enumerate() {
            assert_eq!(qwt.get(i), Some(symbol));
        }
    }
}

#[test]
fn test_serialize() {
    let qwt = HuffQWaveletTree::<_, RSQVector512>::new(&mut [0_u8; 10]);
    let s = bincode::serialize(&qwt).unwrap();

    let des_qwt = bincode::deserialize::<HuffQWaveletTree<u8, RSQVector512>>(&s).unwrap();

    assert_eq!(des_qwt, qwt);
}

fn gen_seq(n: usize, sigma: usize) -> Vec<u64> {
    let mut rng = rand::thread_rng();
    (0..n).map(|_| rng.gen_range(0..sigma) as u64).collect()
}

#[test]
fn test_big_sigma() {
    let seq = gen_seq(100_000, 10_000);

    let qwt = HuffQWaveletTree::<u64, RSQVector512>::from(seq.clone());

    assert_eq!(seq, qwt.iter().collect::<Vec<_>>());
}

#[test]
fn test_runtinme_get() {
    let n = 100_000;
    let sigma = 140;
    let n_queries = 10_000;

    let seq = gen_seq(n, sigma);
    let queries = gen_seq(n_queries, n);

    let qwt = HQWT256::from(seq.clone());

    let mut check = 0;

    let mut timer = TimingQueries::new(1, n_queries);

    timer.start();
    for q in queries {
        check ^= qwt.get(q as usize).unwrap();
    }
    timer.stop();

    println!("check {}", check);
    println!("took {:?}", timer.get());
}

// QWT256 took (1099, 1099, 1099)
// HQWT took (1616, 1616, 1616)