Fast and robust slice-based algorithms (e.g., [sorting], [selection], [search]) for
non-contiguous (sub)views into n-dimensional arrays. Reimplements algorithms in [slice] and
[rayon::slice] for [ndarray] with arbitrary memory layout (e.g., non-contiguous).
```rust use ndarray_slice::{ndarray::arr2, Slice1Ext};
// 2-dimensional array of 4 rows and 5 columns. let mut v = arr2(&[[-5, 4, 1, -3, 2], // row 0, axis 0 [ 8, 3, 2, 4, 8], // row 1, axis 0 [38, 9, 3, 0, 3], // row 2, axis 0 [ 4, 9, 0, 8, -1]]); // row 3, axis 0 // \ \ \ // column 0 \ column 4 axis 1 // column 2 axis 1
// Mutable subview into the last column. let mut column = v.column_mut(4);
// Due to row-major memory layout, columns are non-contiguous // and hence cannot be sorted by viewing them as mutable slices. asserteq!(column.asslice_mut(), None);
// Instead, sorting is specifically implemented for non-contiguous // mutable (sub)views. column.sort_unstable();
assert!(v == arr2(&[[-5, 4, 1, -3, -1], [ 8, 3, 2, 4, 2], [38, 9, 3, 0, 3], [ 4, 9, 0, 8, 8]])); // \ // column 4 sorted, others untouched ```
Complexities where n is the length of the (sub)view and m the count of indices to select.
| Resource | Complexity | Sorting (stable) | Sorting (unstable) | Selection (unstable) | Bulk Selection (unstable) | |----------|------------|------------------|---------------------|--------------------------|---------------------------| | Time | Best | O(n) | O(n) | O(n) | O(n log m) | | Time | Expected | O(n log n) | O(n log n) | O(n) | O(n log m) | | Time | Worst | O(n log n) | O(n log n) | O(n log n) | O(n log n log m) | | Space | Best | O(1) | O(1) | O(1) | O(m) | | Space | Expected | O(n/2) | O(log n) | O(log n) | O(m+log n) | | Spoce | Worst | O(n/2) | O(log n) | O(log n) | O(m+log n) |
SliceExt trait for n-dimensional array or (sub)view with methods expecting Axis as
their first argument. Comparing methods will always be suffixed with _by or _by_key
defining how to compare multi-dimensional elements (e.g., columns) along the provided axis
of interest (e.g., rows).See the release history to keep track of the development.
alloc for stable sort/sort_by/sort_by_key. Enabled by std.std for stable sort_by_cached_key. Enabled by default or rayon.rayon for parallel par_sort*/par_select_many_nth_unstable*.Copyright © 2023 Rouven Spreckels rs@qu1x.dev
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