leto 0.46.0

N-dimensional strided arrays, zero-copy views, and storage backends
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

#![expect(
    clippy::unwrap_used,
    reason = "test scope: failed precondition = test failure"
)]

use leto::{Array, Layout, LetoError, SliceArg, VecStorage};
use proptest::prelude::*;

proptest! {
    #[test]
    fn c_contiguous_offsets_match_row_major_formula(
        rows in 1usize..8,
        cols in 1usize..8,
        depth in 1usize..8,
        row in 0usize..8,
        col in 0usize..8,
        lane in 0usize..8,
    ) {
        let row = row % rows;
        let col = col % cols;
        let lane = lane % depth;
        let layout = Layout::c_contiguous([rows, cols, depth]).unwrap();

        prop_assert_eq!(
            layout.offset_of([row, col, lane]).unwrap(),
            (row * cols * depth) + (col * depth) + lane
        );
        prop_assert_eq!(layout.checked_size().unwrap(), rows * cols * depth);
        prop_assert!(layout.validate_storage_len(rows * cols * depth).is_ok());
    }

    #[test]
    fn f_contiguous_offsets_match_column_major_formula(
        rows in 1usize..8,
        cols in 1usize..8,
        depth in 1usize..8,
        row in 0usize..8,
        col in 0usize..8,
        lane in 0usize..8,
    ) {
        let row = row % rows;
        let col = col % cols;
        let lane = lane % depth;
        let layout = Layout::f_contiguous([rows, cols, depth]).unwrap();

        prop_assert_eq!(
            layout.offset_of([row, col, lane]).unwrap(),
            row + (col * rows) + (lane * rows * cols)
        );
        prop_assert_eq!(layout.checked_size().unwrap(), rows * cols * depth);
        prop_assert!(layout.validate_storage_len(rows * cols * depth).is_ok());
    }

    #[test]
    fn transposed_views_preserve_physical_values(
        rows in 1usize..7,
        cols in 1usize..7,
        depth in 1usize..7,
        a in 0usize..7,
        b in 0usize..7,
        c in 0usize..7,
    ) {
        let a = a % depth;
        let b = b % rows;
        let c = c % cols;
        let len = rows * cols * depth;
        let array = Array::from_shape_vec([rows, cols, depth], (0..len).collect::<Vec<_>>()).unwrap();

        let transposed = array.transpose([2, 0, 1]).unwrap();

        prop_assert_eq!(transposed.shape(), [depth, rows, cols]);
        prop_assert_eq!(
            *transposed.get([a, b, c]).unwrap(),
            *array.get([b, c, a]).unwrap()
        );
    }

    #[test]
    fn reverse_slices_preserve_leto_style_value_order(
        rows in 1usize..8,
        cols in 1usize..8,
        row in 0usize..8,
        col in 0usize..8,
    ) {
        let row = row % rows;
        let col = col % cols;
        let len = rows * cols;
        let array = Array::from_shape_vec([rows, cols], (0..len).collect::<Vec<_>>()).unwrap();

        let view = array
            .slice_with::<2>(&[
                SliceArg::range(Some(-1), None, -1),
                SliceArg::All,
            ])
            .unwrap();

        prop_assert_eq!(view.shape(), [rows, cols]);
        prop_assert_eq!(
            *view.get([row, col]).unwrap(),
            *array.get([rows - 1 - row, col]).unwrap()
        );
    }

    #[test]
    fn broadcasted_singleton_axis_preserves_source_values(
        rows in 0usize..8,
        cols in 1usize..8,
        row in 0usize..8,
        col in 0usize..8,
    ) {
        let col = col % cols;
        let source = Array::from_shape_vec([1, cols], (0..cols).collect::<Vec<_>>()).unwrap();
        let broadcast = source.broadcast([rows, cols]).unwrap();

        prop_assert_eq!(broadcast.shape(), [rows, cols]);
        let expected_row_stride = if rows == 1 { cols as isize } else { 0 };
        prop_assert_eq!(broadcast.strides(), [expected_row_stride, 1]);

        if rows > 0 {
            let row = row % rows;
            prop_assert_eq!(*broadcast.get([row, col]).unwrap(), *source.get([0, col]).unwrap());
        }
    }

    #[test]
    fn negative_stride_layout_storage_span_is_checked(len in 1usize..32) {
        let valid = Layout::try_new([len], [-1], len - 1).unwrap();

        prop_assert_eq!(valid.checked_min_max_offsets().unwrap(), (0, len - 1));
        prop_assert!(valid.validate_storage_len(len).is_ok());

        if len > 1 {
            // Walking [0..len) at stride -1 from base 0 addresses offset
            // -(len - 1). The rejection now happens at construction rather
            // than in the downstream offset query.
            let rejects_negative_span = matches!(
                Layout::try_new([len], [-1], 0),
                Err(LetoError::StorageError { .. })
            );
            prop_assert!(rejects_negative_span);
        }
    }

    #[test]
    fn empty_axis_layouts_have_zero_size_without_storage_access(
        rows in 0usize..8,
        depth in 0usize..8,
    ) {
        let layout = Layout::c_contiguous([rows, 0, depth]).unwrap();
        let array = Array::<usize, _, 3>::new(layout, VecStorage::new(Vec::new())).unwrap();

        prop_assert_eq!(layout.checked_size().unwrap(), 0);
        prop_assert_eq!(layout.checked_min_max_offsets().unwrap(), (0, 0));
        prop_assert!(layout.validate_storage_len(0).is_ok());
        prop_assert_eq!(array.size(), 0);
        prop_assert_eq!(array.view().as_slice().unwrap(), &[]);
    }

    #[test]
    fn composed_slices_preserve_original_values(
        rows in 2usize..10,
        cols in 2usize..10,
        row_start in 0usize..10,
        row_take in 1usize..10,
        col_start in 0usize..10,
        col_take in 1usize..10,
        out_row in 0usize..10,
        out_col in 0usize..10,
    ) {
        let row_start = row_start % rows;
        let row_take = row_take.min(rows - row_start);
        let row_mid = row_start + row_take;
        let col_start = col_start % cols;
        let col_take = col_take.min(cols - col_start);
        let col_mid = col_start + col_take;
        let len = rows * cols;
        let array = Array::from_shape_vec([rows, cols], (0..len).collect::<Vec<_>>()).unwrap();

        let row_slice = array
            .slice_with::<2>(&[
                SliceArg::range(Some(row_start as isize), Some(row_mid as isize), 1),
                SliceArg::All,
            ])
            .unwrap();
        let composed = row_slice
            .slice_with::<2>(&[
                SliceArg::All,
                SliceArg::range(Some(col_start as isize), Some(col_mid as isize), 1),
            ])
            .unwrap();

        let out_row = out_row % row_take;
        let out_col = out_col % col_take;

        prop_assert_eq!(composed.shape(), [row_take, col_take]);
        prop_assert_eq!(
            *composed.get([out_row, out_col]).unwrap(),
            *array.get([row_start + out_row, col_start + out_col]).unwrap()
        );
    }
}