p3_matrix/
stack.rs

1use core::ops::Deref;
2
3use crate::Matrix;
4
5/// A combination of two matrices, stacked together vertically.
6#[derive(Copy, Clone, Debug)]
7pub struct VerticalPair<First, Second> {
8    first: First,
9    second: Second,
10}
11
12impl<First, Second> VerticalPair<First, Second> {
13    pub fn new<T>(first: First, second: Second) -> Self
14    where
15        T: Send + Sync,
16        First: Matrix<T>,
17        Second: Matrix<T>,
18    {
19        assert_eq!(first.width(), second.width());
20        Self { first, second }
21    }
22}
23
24impl<T: Send + Sync, First: Matrix<T>, Second: Matrix<T>> Matrix<T>
25    for VerticalPair<First, Second>
26{
27    fn width(&self) -> usize {
28        self.first.width()
29    }
30
31    fn height(&self) -> usize {
32        self.first.height() + self.second.height()
33    }
34
35    type Row<'a>
36        = EitherRow<First::Row<'a>, Second::Row<'a>>
37    where
38        Self: 'a;
39
40    fn get(&self, r: usize, c: usize) -> T {
41        if r < self.first.height() {
42            self.first.get(r, c)
43        } else {
44            self.second.get(r - self.first.height(), c)
45        }
46    }
47
48    fn row(&self, r: usize) -> Self::Row<'_> {
49        if r < self.first.height() {
50            EitherRow::Left(self.first.row(r))
51        } else {
52            EitherRow::Right(self.second.row(r - self.first.height()))
53        }
54    }
55
56    fn row_slice(&self, r: usize) -> impl Deref<Target = [T]> {
57        if r < self.first.height() {
58            EitherRow::Left(self.first.row_slice(r))
59        } else {
60            EitherRow::Right(self.second.row_slice(r - self.first.height()))
61        }
62    }
63}
64
65/// We use this to wrap both the row iterator and the row slice.
66#[derive(Debug)]
67pub enum EitherRow<L, R> {
68    Left(L),
69    Right(R),
70}
71
72impl<T, L, R> Iterator for EitherRow<L, R>
73where
74    L: Iterator<Item = T>,
75    R: Iterator<Item = T>,
76{
77    type Item = T;
78
79    fn next(&mut self) -> Option<Self::Item> {
80        match self {
81            EitherRow::Left(l) => l.next(),
82            EitherRow::Right(r) => r.next(),
83        }
84    }
85}
86
87impl<T, L, R> Deref for EitherRow<L, R>
88where
89    L: Deref<Target = [T]>,
90    R: Deref<Target = [T]>,
91{
92    type Target = [T];
93    fn deref(&self) -> &Self::Target {
94        match self {
95            EitherRow::Left(l) => l,
96            EitherRow::Right(r) => r,
97        }
98    }
99}
p3_matrix/stack.rs

p3_matrix/
stack.rs
