vortex-mask 0.69.0

Vortex Mask - sorted, unique, non-negative integers
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

// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright the Vortex contributors

use crate::AllOr;
use crate::Mask;

impl Mask {
    /// Take the intersection of the `mask` with the set of true values in `self`.
    ///
    /// We are more interested in low selectivity `self` (as indices) with a boolean buffer mask,
    /// so we don't optimize for other cases, yet.
    ///
    /// Note: we might be able to accelerate this function on x86 with BMI, see:
    /// <https://www.microsoft.com/en-us/research/uploads/prod/2023/06/parquet-select-sigmod23.pdf>
    ///
    /// # Examples
    ///
    /// Keep the third and fifth set values from mask `m1`:
    /// ```
    /// use vortex_mask::Mask;
    ///
    /// let m1 = Mask::from_iter([true, false, false, true, true, true, false, true]);
    /// let m2 = Mask::from_iter([false, false, true, false, true]);
    /// assert_eq!(
    ///     m1.intersect_by_rank(&m2),
    ///     Mask::from_iter([false, false, false, false, true, false, false, true])
    /// );
    /// ```
    pub fn intersect_by_rank(&self, mask: &Mask) -> Mask {
        assert_eq!(self.true_count(), mask.len());

        match (self.indices(), mask.indices()) {
            (AllOr::All, _) => mask.clone(),
            (_, AllOr::All) => self.clone(),
            (AllOr::None, _) | (_, AllOr::None) => Self::new_false(self.len()),

            (AllOr::Some(self_indices), AllOr::Some(mask_indices)) => {
                Self::from_indices(
                    self.len(),
                    mask_indices
                        .iter()
                        .map(|idx|
                            // This is verified as safe because we know that the indices are less than the
                            // mask.len() and we known mask.len() <= self.len(),
                            // implied by `self.true_count() == mask.len()`.
                            unsafe{*self_indices.get_unchecked(*idx)})
                        .collect(),
                )
            }
        }
    }
}

#[cfg(test)]
mod test {
    use rstest::rstest;
    use vortex_buffer::BitBuffer;

    use crate::Mask;

    #[test]
    fn mask_bitand_all_as_bit_and() {
        let this = Mask::from_buffer(BitBuffer::from_iter(vec![true, true, true, true, true]));
        let mask = Mask::from_buffer(BitBuffer::from_iter(vec![false, true, false, true, true]));
        assert_eq!(
            this.intersect_by_rank(&mask),
            Mask::from_indices(5, vec![1, 3, 4])
        );
    }

    #[test]
    fn mask_bitand_all_true() {
        let this = Mask::from_buffer(BitBuffer::from_iter(vec![false, false, true, true, true]));
        let mask = Mask::from_buffer(BitBuffer::from_iter(vec![true, true, true]));
        assert_eq!(
            this.intersect_by_rank(&mask),
            Mask::from_indices(5, vec![2, 3, 4])
        );
    }

    #[test]
    fn mask_bitand_true() {
        let this = Mask::from_buffer(BitBuffer::from_iter(vec![true, false, false, true, true]));
        let mask = Mask::from_buffer(BitBuffer::from_iter(vec![true, false, true]));
        assert_eq!(
            this.intersect_by_rank(&mask),
            Mask::from_indices(5, vec![0, 4])
        );
    }

    #[test]
    fn mask_bitand_false() {
        let this = Mask::from_buffer(BitBuffer::from_iter(vec![true, false, false, true, true]));
        let mask = Mask::from_buffer(BitBuffer::from_iter(vec![false, false, false]));
        assert_eq!(this.intersect_by_rank(&mask), Mask::from_indices(5, vec![]));
    }

    #[test]
    fn mask_intersect_by_rank_all_false() {
        let this = Mask::AllFalse(10);
        let mask = Mask::AllFalse(0);
        assert_eq!(this.intersect_by_rank(&mask), Mask::AllFalse(10));
    }

    #[rstest]
    #[case::all_true_with_all_true(
        Mask::new_true(5),
        Mask::new_true(5),
        vec![0, 1, 2, 3, 4]
    )]
    #[case::all_true_with_all_false(
        Mask::new_true(5),
        Mask::new_false(5),
        vec![]
    )]
    #[case::all_false_with_any(
        Mask::new_false(10),
        Mask::new_true(0),
        vec![]
    )]
    #[case::indices_with_all_true(
        Mask::from_indices(10, vec![2, 5, 7, 9]),
        Mask::new_true(4),
        vec![2, 5, 7, 9]
    )]
    #[case::indices_with_all_false(
        Mask::from_indices(10, vec![2, 5, 7, 9]),
        Mask::new_false(4),
        vec![]
    )]
    fn test_intersect_by_rank_special_cases(
        #[case] base_mask: Mask,
        #[case] rank_mask: Mask,
        #[case] expected_indices: Vec<usize>,
    ) {
        let result = base_mask.intersect_by_rank(&rank_mask);

        match result.indices() {
            crate::AllOr::All => assert_eq!(expected_indices.len(), result.len()),
            crate::AllOr::None => assert!(expected_indices.is_empty()),
            crate::AllOr::Some(indices) => assert_eq!(indices, &expected_indices[..]),
        }
    }

    #[test]
    fn test_intersect_by_rank_example() {
        // Example from the documentation
        let m1 = Mask::from_iter([true, false, false, true, true, true, false, true]);
        let m2 = Mask::from_iter([false, false, true, false, true]);
        let result = m1.intersect_by_rank(&m2);
        let expected = Mask::from_iter([false, false, false, false, true, false, false, true]);
        assert_eq!(result, expected);
    }

    #[test]
    #[should_panic]
    fn test_intersect_by_rank_wrong_length() {
        let m1 = Mask::from_indices(10, vec![2, 5, 7]); // 3 true values
        let m2 = Mask::new_true(5); // 5 true values - doesn't match
        m1.intersect_by_rank(&m2);
    }

    #[rstest]
    #[case::single_element(
        vec![3],
        vec![true],
        vec![3]
    )]
    #[case::single_element_masked(
        vec![3],
        vec![false],
        vec![]
    )]
    #[case::alternating(
        vec![0, 2, 4, 6, 8],
        vec![true, false, true, false, true],
        vec![0, 4, 8]
    )]
    #[case::consecutive(
        vec![5, 6, 7, 8, 9],
        vec![false, true, true, true, false],
        vec![6, 7, 8]
    )]
    fn test_intersect_by_rank_patterns(
        #[case] base_indices: Vec<usize>,
        #[case] rank_pattern: Vec<bool>,
        #[case] expected_indices: Vec<usize>,
    ) {
        let base = Mask::from_indices(10, base_indices);
        let rank = Mask::from_iter(rank_pattern);
        let result = base.intersect_by_rank(&rank);

        match result.indices() {
            crate::AllOr::Some(indices) => assert_eq!(indices, &expected_indices[..]),
            crate::AllOr::None => assert!(expected_indices.is_empty()),
            _ => panic!("Unexpected result"),
        }
    }
}