forester 0.0.3

A crate for implementing various flavors of random forests and decision trees.
Documentation 
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

//! Trait for computing the mean of an iterator's values.

/// Trait for computing the mean of an iterator's values.
///
/// The trait is only implemented for floating point primitives (`f32` and `f64`) but also accepts
/// integer items. (The mean of e.g. `[1, 2, 2]` is not an integer). 
pub trait IterMean<A=Self>
{
    fn mean<I: ExactSizeIterator<Item=A>>(iter: I) -> Self;
}

macro_rules! impl_mean {
    ($a:ident -> $b:ident) => (
        impl IterMean<$a> for $b {
            fn mean<I: ExactSizeIterator<Item=$a>>(iter: I) -> $b {
                let n = iter.len() as $b;
                let sum: $a = iter.sum();
                sum as $b / n
            }
        }

        impl<'a> IterMean<&'a $a> for $b {
            fn mean<I: ExactSizeIterator<Item=&'a $a>>(iter: I) -> $b {
                let n = iter.len() as $b;
                let sum: $a = iter.sum();
                sum as $b / n
            }
        }
    )
}

impl_mean! { f32 -> f32 }
impl_mean! { f64 -> f32 }
impl_mean! { i8 -> f32 }
impl_mean! { u8 -> f32 }
impl_mean! { i16 -> f32 }
impl_mean! { u16 -> f32 }
impl_mean! { i32 -> f32 }
impl_mean! { u32 -> f32 }
impl_mean! { i64 -> f32 }
impl_mean! { u64 -> f32 }
impl_mean! { isize -> f32 }
impl_mean! { usize -> f32 }

impl_mean! { f32 -> f64 }
impl_mean! { f64 -> f64 }
impl_mean! { i8 -> f64 }
impl_mean! { u8 -> f64 }
impl_mean! { i16 -> f64 }
impl_mean! { u16 -> f64 }
impl_mean! { i32 -> f64 }
impl_mean! { u32 -> f64 }
impl_mean! { i64 -> f64 }
impl_mean! { u64 -> f64 }
impl_mean! { isize -> f64 }
impl_mean! { usize -> f64 }


#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn iter_mean() {
        let x = vec![1.0f32, 2.0, 3.0, 4.0];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);

        let x = vec![1.0f64, 2.0, 3.0, 4.0];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);

        let x = vec![1i8, 2, 3, -4];
        assert_eq!(f32::mean(x.iter()), 0.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 0.5);
        assert_eq!(f64::mean(x.iter()), 0.5);
        assert_eq!(f64::mean(x.into_iter()), 0.5);

        let x = vec![1u8, 2, 3, 4];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);

        let x = vec![1i16, 2, 3, -4];
        assert_eq!(f32::mean(x.iter()), 0.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 0.5);
        assert_eq!(f64::mean(x.iter()), 0.5);
        assert_eq!(f64::mean(x.into_iter()), 0.5);

        let x = vec![1u16, 2, 3, 4];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);

        let x = vec![1i32, 2, 3, -4];
        assert_eq!(f32::mean(x.iter()), 0.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 0.5);
        assert_eq!(f64::mean(x.iter()), 0.5);
        assert_eq!(f64::mean(x.into_iter()), 0.5);

        let x = vec![1u32, 2, 3, 4];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);

        let x = vec![1i64, 2, 3, -4];
        assert_eq!(f32::mean(x.iter()), 0.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 0.5);
        assert_eq!(f64::mean(x.iter()), 0.5);
        assert_eq!(f64::mean(x.into_iter()), 0.5);

        let x = vec![1u64, 2, 3, 4];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);

        let x = vec![1isize, 2, 3, -4];
        assert_eq!(f32::mean(x.iter()), 0.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 0.5);
        assert_eq!(f64::mean(x.iter()), 0.5);
        assert_eq!(f64::mean(x.into_iter()), 0.5);

        let x = vec![1usize, 2, 3, 4];
        assert_eq!(f32::mean(x.iter()), 2.5);
        assert_eq!(f32::mean(x.clone().into_iter()), 2.5);
        assert_eq!(f64::mean(x.iter()), 2.5);
        assert_eq!(f64::mean(x.into_iter()), 2.5);
    }
}