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

use crate::{Kernel, KernelMul};
use std::fmt::Debug;
use std::marker::PhantomData;
use std::{error::Error, ops::Add, ops::Mul};

#[derive(Clone, Debug)]
pub struct KernelAdd<L, R, T>
where
    L: Kernel<T>,
    R: Kernel<T>,
    T: Clone + Debug,
{
    lhs: L,
    rhs: R,
    phantom: PhantomData<T>,
}

impl<L, R, T> KernelAdd<L, R, T>
where
    L: Kernel<T>,
    R: Kernel<T>,
    T: Clone + Debug,
{
    pub fn new(lhs: L, rhs: R) -> Self {
        Self {
            lhs,
            rhs,
            phantom: PhantomData,
        }
    }
}

impl<L, R, T> Kernel<T> for KernelAdd<L, R, T>
where
    L: Kernel<T>,
    R: Kernel<T>,
    T: Clone + Debug,
{
    fn params_len(&self) -> usize {
        self.lhs.params_len() + self.rhs.params_len()
    }

    fn value(
        &self,
        params: &[f64],
        x: &T,
        xprime: &T,
        with_grad: bool,
    ) -> Result<(f64, Vec<f64>), Box<dyn Error>> {
        let lhs_params_len = self.lhs.params_len();
        let (fx, gfx) = self
            .lhs
            .value(&params[..lhs_params_len], x, xprime, with_grad)?;
        let (gx, ggx) = self
            .rhs
            .value(&params[lhs_params_len..], x, xprime, with_grad)?;

        let hx = fx + gx;

        let ghx = if !with_grad {
            vec![]
        } else {
            let ghx = [gfx, ggx].concat();

            ghx
        };

        Ok((hx, ghx))
    }
}

impl<Rhs, L, R, T> Add<Rhs> for KernelAdd<L, R, T>
where
    Rhs: Kernel<T>,
    L: Kernel<T>,
    R: Kernel<T>,
    T: Clone + Debug,
{
    type Output = KernelAdd<Self, Rhs, T>;

    fn add(self, rhs: Rhs) -> Self::Output {
        Self::Output::new(self, rhs)
    }
}

impl<Rhs, L, R, T> Mul<Rhs> for KernelAdd<L, R, T>
where
    Rhs: Kernel<T>,
    L: Kernel<T>,
    R: Kernel<T>,
    T: Clone + Debug,
{
    type Output = KernelMul<Self, Rhs, T>;

    fn mul(self, rhs: Rhs) -> Self::Output {
        Self::Output::new(self, rhs)
    }
}