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

use std::any::Any;

use tracing::Level;

use crate::{Primitive, Shape, Tensor};

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Broadcast {
    pub shape: Vec<usize>,
}
impl Broadcast {
    pub fn new(shape: impl Shape) -> Self {
        Self {
            shape: shape.shape().to_vec(),
        }
    }

    pub fn shape(&self) -> &[usize] {
        &self.shape
    }
}

impl Primitive for Broadcast {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn dot_label(&self) -> String {
        format!("Broadcast({:?})", self.shape)
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        tangent_x.broadcast_to(self.shape())
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let shape = x.shape().to_vec();
        let diff = cotangent.ndim() - shape.ndim();
        let mut dims = Vec::new();
        for i in 0..cotangent.ndim() {
            if i < diff || shape[i - diff] != cotangent.shape_at(i) {
                dims.push(i);
            }
        }
        let cotangent_x = cotangent.sum((dims, true)).reshape(&shape);
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Reshape {
    pub shape: Vec<usize>,
}
impl Reshape {
    pub fn new(shape: impl Shape) -> Self {
        Self {
            shape: shape.shape().to_vec(),
        }
    }

    pub fn shape(&self) -> &[usize] {
        &self.shape
    }
}

impl Primitive for Reshape {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    fn dot_label(&self) -> String {
        format!("Reshape({:?})", self.shape)
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, output: &Tensor, _primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        tangent_x.reshape(self.shape())
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent.reshape(x);
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Transpose {
    pub dim0: usize,
    pub dim1: usize,
}

impl Transpose {
    pub fn new(dim0: usize, dim1: usize) -> Self {
        Self { dim0, dim1 }
    }

    pub fn dim0(&self) -> usize {
        self.dim0
    }

    pub fn dim1(&self) -> usize {
        self.dim1
    }
}

impl Primitive for Transpose {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    fn dot_label(&self) -> String {
        format!("Transpose({}, {})", self.dim0(), self.dim1())
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, _primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        tangent_x.transpose(self.dim0, self.dim1)
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, _primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let cotangent_x = cotangent.transpose(self.dim1, self.dim0);
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct ToContiguous;

impl Primitive for ToContiguous {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, _primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        todo!()
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, _primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        todo!()
    }
}