spaces 6.0.0

Set/space primitives for defining machine learning problems.
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
138
139
140
141
142
143
144
145
146
147

use std::ops::Mul;

/// Measure of the cardinality (#) of a set.
///
/// `Card` is used to represent the number of possible values that are contained by a space. Take,
/// for example, a 2-dimensional space, each with a finite set of values. In this case we have the
/// following:
/// ```
/// use spaces::{Space, Card};
///
/// let d1 = 0..5;
/// let d2 = 0..10;
/// let space = (d1, d2);
///
/// assert_eq!(space.card(), Card::Finite(50));
/// ```
///
/// Internally, this above code does the following:
///
/// ```
/// use spaces::Card;
///
/// let s1 = Card::Finite(5);
/// let s2 = Card::Finite(10);
///
/// assert_eq!(s1 * s2, Card::Finite(50));
/// ```
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "serialize", derive(Serialize, Deserialize))]
pub enum Card {
    Finite(usize),
    Infinite,
}

impl Card {
    pub fn is_zero(&self) -> bool {
        match self {
            &Card::Finite(n) => n == 0,
            _ => false,
        }
    }

    pub fn is_finite(&self) -> bool {
        match self {
            &Card::Finite(_) => true,
            _ => false,
        }
    }

    pub fn is_infinite(&self) -> bool {
        match self {
            &Card::Infinite => true,
            _ => false,
        }
    }

    pub fn expect_finite(&self, msg: &str) -> usize {
        match self {
            &Card::Finite(n) => n,
            _ => panic!("{}", msg),
        }
    }
}

impl Mul for Card {
    type Output = Card;

    fn mul(self, rhs: Card) -> Card {
        match (self, rhs) {
            (Card::Infinite, _) | (_, Card::Infinite) => Card::Infinite,
            (Card::Finite(0), Card::Finite(a)) | (Card::Finite(a), Card::Finite(0)) =>
                Card::Finite(a),
            (Card::Finite(ls), Card::Finite(rs)) => Card::Finite(ls * rs),
        }
    }
}

impl Into<usize> for Card {
    fn into(self) -> usize {
        match self {
            Card::Finite(e) => e,
            _ => panic!("Card type has no integer representation."),
        }
    }
}

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

    #[test]
    fn test_equality() {
        assert_eq!(Card::Infinite, Card::Infinite);

        assert_eq!(Card::Finite(0), Card::Finite(0));
        assert_eq!(Card::Finite(1), Card::Finite(1));
        assert_eq!(Card::Finite(5), Card::Finite(5));
        assert_eq!(Card::Finite(10), Card::Finite(10));
    }

    #[test]
    fn test_inequality() {
        assert_ne!(Card::Finite(0), Card::Infinite);

        assert_ne!(Card::Infinite, Card::Finite(0));
        assert_ne!(Card::Infinite, Card::Finite(1));

        assert_ne!(Card::Finite(0), Card::Finite(1));
        assert_ne!(Card::Finite(1), Card::Finite(0));
        assert_ne!(Card::Finite(1), Card::Infinite);
        assert_ne!(Card::Finite(1), Card::Finite(10));
    }

    #[test]
    fn test_mul() {
        assert_eq!(Card::Finite(0), Card::Finite(0));
        assert_eq!(Card::Infinite * Card::Infinite, Card::Infinite);

        assert_eq!(Card::Finite(0) * Card::Infinite, Card::Infinite);
        assert_eq!(Card::Infinite * Card::Finite(0), Card::Infinite);

        assert_eq!(Card::Finite(1) * Card::Infinite, Card::Infinite);
        assert_eq!(Card::Finite(5) * Card::Infinite, Card::Infinite);

        assert_eq!(Card::Finite(1) * Card::Finite(1), Card::Finite(1));
        assert_eq!(Card::Finite(1) * Card::Finite(5), Card::Finite(5));
        assert_eq!(Card::Finite(5) * Card::Finite(1), Card::Finite(5));
        assert_eq!(Card::Finite(5) * Card::Finite(5), Card::Finite(25));
    }

    #[test]
    #[should_panic]
    fn test_into_infinite() {
        let s = Card::Infinite;
        let _: usize = s.into();
    }

    #[test]
    fn test_into_finite() {
        for i in vec![0, 1, 5, 10] {
            let d = Card::Finite(i);
            let v: usize = d.into();

            assert_eq!(v, i);
        }
    }
}