iterstats 0.7.0

Statistics for rust iterators.
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

//! Caculate the mean/average.

use crate::Iterstats;

/// Calculate the mean of an iterator.
pub trait Mean<A = Self>: Sized {
    /// The type of the output.
    type Output;

    /// Calculate the mean.
    fn mean<I: Iterator<Item = A> + Clone>(iter: I) -> Self::Output;
}

macro_rules! mean_impl {
    ($typ:ty) => {
        impl Mean for $typ {
            type Output = $typ;

            fn mean<I: Iterator<Item = Self> + Clone>(iter: I) -> Self::Output {
                let sum = iter.clone().sum::<$typ>();
                sum / (iter.count() as $typ)
            }
        }

        impl Mean for &$typ {
            type Output = $typ;

            fn mean<I: Iterator<Item = Self> + Clone>(iter: I) -> Self::Output {
                iter.map(|i| *i).mean()
            }
        }
    };
}

mean_impl!(f64);
mean_impl!(f32);

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

    macro_rules! test_mean {
        ($name:ident: $iterty:ty as $iter:expr ; into_iter => nan ) => {
            paste! {
                #[test]
                fn [<$name:snake _into_iter>]() {
                    let mean = <$iterty>::mean($iter.into_iter());
                    assert!(mean.is_nan());
                }
            }
        };
        ($name:ident: $iterty:ty as $iter:expr ; iter => nan ) => {
            paste! {
                #[test]
                fn [<$name:snake _iter>]() {
                    let mean = <&$iterty>::mean($iter.iter());
                    assert!(mean.is_nan());
                }
            }
        };
        ($name:ident: $iterty:ty as $iter:expr => nan ) => {
            test_mean!($name: $iterty as $iter; into_iter => nan);
            test_mean!($name: $iterty as $iter; iter => nan);
        };
        ($name:ident: $iterty:ty as $iter:expr ; into_iter => $expected:expr ) => {
            paste! {
                #[test]
                fn [<$name:snake _into_iter>]() {
                    let mean = <$iterty>::mean($iter.into_iter());
                    assert_eq!(mean, $expected);
                }
            }
        };
        ($name:ident: $iterty:ty as $iter:expr ; iter => $expected:expr ) => {
            paste! {
                #[test]
                fn [<$name:snake _iter>]() {
                    let mean = <&$iterty>::mean($iter.iter());
                    assert_eq!(mean, $expected);
                }
            }
        };
        ($name:ident: $iterty:ty as $iter:expr => $expected:expr ) => {
            test_mean!($name: $iterty as $iter; into_iter => $expected);
            test_mean!($name: $iterty as $iter; iter => $expected);
        };
    }

    test_mean!(f64: f64 as [1.0, 2.0, 3.0, 4.0] => 2.5 );
    test_mean!(f64_max: f64 as [f64::MAX, f64::MAX] => f64::INFINITY);
    test_mean!(f64_min: f64 as [f64::MIN, f64::MIN] => f64::NEG_INFINITY);
    test_mean!(f64_minmax: f64 as [f64::MIN, f64::MAX] => 0.);
    test_mean!(f64_nan: f64 as [1.0, 2.0, f64::NAN, 4.0] => nan);
    test_mean!(f64_inf: f64 as [1.0, 2.0, f64::INFINITY, 4.0] => f64::INFINITY);
    test_mean!(f64_neg_inf: f64 as [1.0, 2.0, f64::NEG_INFINITY, 4.0] => f64::NEG_INFINITY);

    test_mean!(f32: f32 as [1.0, 2.0, 3.0, 4.0] => 2.5 );
    test_mean!(f32_max: f32 as [f32::MAX, f32::MAX] => f32::INFINITY);
    test_mean!(f32_min: f32 as [f32::MIN, f32::MIN] => f32::NEG_INFINITY);
    test_mean!(f32_minmax: f32 as [f32::MIN, f32::MAX] => 0.);
    test_mean!(f32_nan: f32 as [1.0, 2.0, f32::NAN, 4.0] => nan);
    test_mean!(f32_inf: f32 as [1.0, 2.0, f32::INFINITY, 4.0] => f32::INFINITY);
    test_mean!(f32_neg_inf: f32 as [1.0, 2.0, f32::NEG_INFINITY, 4.0] => f32::NEG_INFINITY);
}