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

use std::ops::{Mul, Add};

use crate::{matrix_init, Matrix};

pub trait MMul<Rhs>: Matrix
where
    Self::Output: Matrix
{
    type Output;
    
    /// Returns the matrix product
    /// 
    /// AB
    /// 
    /// # Arguments
    /// 
    /// * `rhs` - A scalar or a matrix with height equal this matrix's length
    /// 
    /// # Examples
    /// 
    /// ```rust
    /// // Scaling
    /// let a = [
    ///     [1.0, 2.0],
    ///     [3.0, 4.0]
    /// ];
    /// let b = 2.0;
    /// let ab = [
    ///     [2.0, 4.0],
    ///     [6.0, 8.0]
    /// ];
    /// assert_eq!(a.mul(b), ab)
    /// 
    /// // Matrix multiplication
    /// let a = [
    ///     [1.0],
    ///     [2.0],
    ///     [3.0]
    /// ];
    /// let b = [
    ///     [1.0, 2.0, 3.0]
    /// ];
    /// let ab = [
    ///     [1.0, 2.0, 3.0],
    ///     [2.0, 4.0, 6.0],
    ///     [3.0, 6.0, 9.0]
    /// ];
    /// assert_eq!(a.mul(b), ab)
    /// ```
    fn mul(self, rhs: Rhs) -> Self::Output;
}

impl<F, const L: usize, const H: usize> MMul<F> for [[F; L]; H]
where
    Self: Matrix,
    [[<F as Mul<F>>::Output; L]; H]: Matrix,
    F: Clone + Mul<F>
{
    type Output = [[<F as Mul<F>>::Output; L]; H];
    fn mul(self, rhs: F) -> Self::Output
    {
        matrix_init(|r, c| self[r][c].clone()*rhs.clone())
    }
}

impl<F, const L: usize, const H1: usize, const H2: usize> MMul<[[F; H2]; L]>
for
    [[F; L]; H1]
where
    Self: Matrix,
    [[<F as Mul<F>>::Output; H2]; H1]: Matrix,
    F: Clone + Mul<F>,
    <F as Mul<F>>::Output: Add<<F as Mul<F>>::Output, Output = <F as Mul<F>>::Output>
{
    type Output = [[<F as Mul<F>>::Output; H2]; H1];
    fn mul(self, rhs: [[F; H2]; L]) -> Self::Output
    {
        matrix_init(|r, c| (0..L).map(|i| self[r][i].clone()*rhs[i][c].clone()).reduce(|a, b| a + b).unwrap())
    }
}