cfr 0.4.3

Counterfactual regret minimization solver for two-player zero-sum incomplete-information games
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
148
149
150
151
152
153
154
155
156
157

//! Compact infoset allocators
//!
//! In order to efficiently access mutable state tied to an infoset, we need quick access to it
//! from any infoset. The fastest way to do this is to keep each infoset in a slice, and store the
//! index so we can get mutable access when we want. This also allows us to easily build up
//! parallel memory and access consistent elements with minimal allocations.
//!
//! In order to achieve this, we first build a hash map that preserves insertion order to resolve
//! identical keys to the same index and assocaited values. Then we destruct it and move it into
//! the final boxed slice once we've processed everything.
//!
//! This module contains [Builder] and [OptBuilder]. The only difference is that the latter allows
//! pushing optional values with guaranteed uniqueness (no key).
use indexmap::{map, IndexMap};
use std::hash::Hash;
use std::iter::FusedIterator;

#[derive(Debug, Clone)]
pub struct Builder<K: Hash + Eq, V> {
    map: IndexMap<K, (usize, V)>,
}

impl<K: Hash + Eq, V> Builder<K, V> {
    pub fn new() -> Self {
        Builder {
            map: IndexMap::new(),
        }
    }

    pub fn entry(&mut self, key: K) -> Entry<'_, K, V> {
        let ind = self.map.len();
        match self.map.entry(key) {
            map::Entry::Vacant(ent) => Entry::Vacant(VacantEntry { ind, ent }),
            map::Entry::Occupied(ent) => Entry::Occupied(OccupiedEntry { ent }),
        }
    }
}

impl<K: Hash + Eq, V> IntoIterator for Builder<K, V> {
    type IntoIter = IntoIter<K, V>;
    type Item = <Self::IntoIter as Iterator>::Item;

    fn into_iter(self) -> Self::IntoIter {
        IntoIter {
            iter: self.map.into_iter(),
        }
    }
}

pub struct IntoIter<K, V> {
    iter: map::IntoIter<K, (usize, V)>,
}

impl<K, V> Iterator for IntoIter<K, V> {
    type Item = (K, V);

    fn next(&mut self) -> Option<Self::Item> {
        self.iter.next().map(|(k, (_, v))| (k, v))
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        let len = self.iter.len();
        (len, Some(len))
    }
}

impl<K, V> FusedIterator for IntoIter<K, V> {}

impl<K, V> ExactSizeIterator for IntoIter<K, V> {}

#[derive(Debug, Clone)]
pub struct OptBuilder<K: Hash + Eq, V> {
    counter: usize,
    map: IndexMap<Result<K, usize>, (usize, V)>,
}

impl<K: Hash + Eq, V> OptBuilder<K, V> {
    pub fn new() -> Self {
        OptBuilder {
            counter: 0,
            map: IndexMap::new(),
        }
    }

    pub fn entry(&mut self, key: Option<K>) -> Entry<'_, Result<K, usize>, V> {
        let ind = self.map.len();
        let true_key = key.ok_or_else(|| {
            let res = self.counter;
            self.counter += 1;
            res
        });
        match self.map.entry(true_key) {
            map::Entry::Vacant(ent) => Entry::Vacant(VacantEntry { ind, ent }),
            map::Entry::Occupied(ent) => Entry::Occupied(OccupiedEntry { ent }),
        }
    }
}

impl<K: Hash + Eq, V> IntoIterator for OptBuilder<K, V> {
    type IntoIter = OptIntoIter<K, V>;
    type Item = <Self::IntoIter as Iterator>::Item;

    fn into_iter(self) -> Self::IntoIter {
        OptIntoIter {
            iter: self.map.into_iter(),
        }
    }
}

pub struct OptIntoIter<K, V> {
    iter: map::IntoIter<Result<K, usize>, (usize, V)>,
}

impl<K, V> Iterator for OptIntoIter<K, V> {
    type Item = (Option<K>, V);

    fn next(&mut self) -> Option<Self::Item> {
        self.iter.next().map(|(k, (_, v))| (k.ok(), v))
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        let len = self.iter.len();
        (len, Some(len))
    }
}

impl<K, V> FusedIterator for OptIntoIter<K, V> {}

impl<K, V> ExactSizeIterator for OptIntoIter<K, V> {}

pub struct VacantEntry<'a, K, V> {
    ind: usize,
    ent: map::VacantEntry<'a, K, (usize, V)>,
}

impl<K: Hash + Eq, V> VacantEntry<'_, K, V> {
    pub fn insert(self, val: V) -> usize {
        self.ent.insert((self.ind, val));
        self.ind
    }
}

pub struct OccupiedEntry<'a, K, V> {
    ent: map::OccupiedEntry<'a, K, (usize, V)>,
}

impl<'a, K: Hash + Eq, V> OccupiedEntry<'a, K, V> {
    pub fn get(self) -> (usize, &'a V) {
        let (ind, val) = self.ent.into_mut();
        (*ind, val)
    }
}

pub enum Entry<'a, K, V> {
    Vacant(VacantEntry<'a, K, V>),
    Occupied(OccupiedEntry<'a, K, V>),
}