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#[cfg(doc)]
use crate::Game;
/// Errors that result from game definition errors
///
/// If the object passed into [Game::from_root] doesn't conform to necessary
/// invariants, one of these will be returned.
#[derive(Debug, PartialEq, Eq)]
pub enum GameError {
/// Returned when a chance node has no outcomes.
EmptyChance,
/// Returned when a chance node has a non-positive probability of happening
NonPositiveChance,
/// Returned when a chance node has different probabilities than another node in its infoset
ProbabilitiesNotEqual,
/// Returned when a games infosets don't exhibit perfect recall
///
/// If a game does have perfect recall, then a player's infosets must form a tree, that is for
/// all game nodes with a given infoset the players previous action node must also share the
/// same infoset. We ignore this criterion for single action infosets since they don't actually
/// reflect a decision.
ImperfectRecall,
/// Returned when a player node has no actions.
EmptyPlayer,
/// Returned when the actions of a player node didn't match the order and values of an earlier
/// information set.
///
/// Make sure that all nodes with the same player and information set also have the same
/// actions in the same order.
ActionsNotEqual,
/// Returned when the actions of a player node weren't unique.
///
/// Make sure that all actions of a player node are unique.
ActionsNotUnique,
}
#[cfg(test)]
mod game_errors {
use crate::{Game, GameError, GameNode, IntoGameNode, PlayerNum};
struct Node(GameNode<Node>);
impl IntoGameNode for Node {
type PlayerInfo = &'static str;
type Action = &'static str;
type ChanceInfo = &'static str;
type Outcomes = Vec<(f64, Node)>;
type Actions = Vec<(&'static str, Node)>;
fn into_game_node(self) -> GameNode<Self> {
self.0
}
}
#[test]
fn empty_chance() {
let err_game = Node(GameNode::Chance(None, [].into()));
let err = Game::from_root(err_game).unwrap_err();
assert_eq!(err, GameError::EmptyChance);
}
#[test]
fn non_positive_chance() {
let err_game = Node(GameNode::Chance(
None,
[(0.0, Node(GameNode::Terminal(0.0)))].into(),
));
let err = Game::from_root(err_game).unwrap_err();
assert_eq!(err, GameError::NonPositiveChance);
}
#[test]
fn probabilities_not_equal() {
let err_game = Node(GameNode::Chance(
None,
vec![
(
0.5,
Node(GameNode::Chance(
Some("x"),
vec![
(1.0, Node(GameNode::Terminal(0.0))),
(1.0, Node(GameNode::Terminal(0.0))),
],
)),
),
(
0.5,
Node(GameNode::Chance(
Some("x"),
vec![
(1.0, Node(GameNode::Terminal(0.0))),
(2.0, Node(GameNode::Terminal(0.0))),
],
)),
),
],
));
let err = Game::from_root(err_game).unwrap_err();
assert_eq!(err, GameError::ProbabilitiesNotEqual);
}
#[test]
fn imperfect_recall() {
let err_game = Node(GameNode::Chance(
None,
vec![
(
0.5,
Node(GameNode::Player(
PlayerNum::One,
"x",
vec![
("a", Node(GameNode::Terminal(0.0))),
("b", Node(GameNode::Terminal(0.0))),
],
)),
),
(
0.5,
Node(GameNode::Player(
PlayerNum::One,
"y",
vec![
(
"a",
Node(GameNode::Player(
PlayerNum::One,
// NOTE forgot "y"
"x",
vec![
("a", Node(GameNode::Terminal(0.0))),
("b", Node(GameNode::Terminal(0.0))),
],
)),
),
("b", Node(GameNode::Terminal(0.0))),
],
)),
),
],
));
let err = Game::from_root(err_game).unwrap_err();
assert_eq!(err, GameError::ImperfectRecall);
}
#[test]
fn empty_player() {
let err_game = Node(GameNode::Player(PlayerNum::One, "", [].into()));
let err = Game::from_root(err_game).unwrap_err();
assert_eq!(err, GameError::EmptyPlayer);
}
#[test]
fn actions_not_equal() {
let ord_game = Node(GameNode::Chance(
None,
vec![
(
0.5,
Node(GameNode::Player(
PlayerNum::One,
"x",
vec![
("a", Node(GameNode::Terminal(0.0))),
("b", Node(GameNode::Terminal(0.0))),
],
)),
),
(
0.5,
Node(GameNode::Player(
PlayerNum::One,
"x",
vec![
("b", Node(GameNode::Terminal(0.0))),
("a", Node(GameNode::Terminal(0.0))),
],
)),
),
],
));
let err = Game::from_root(ord_game).unwrap_err();
assert_eq!(err, GameError::ActionsNotEqual);
}
#[test]
fn actions_not_unique() {
let dup_game = Node(GameNode::Player(
PlayerNum::One,
"x",
vec![
("a", Node(GameNode::Terminal(0.0))),
("a", Node(GameNode::Terminal(0.0))),
],
));
let err = Game::from_root(dup_game).unwrap_err();
assert_eq!(err, GameError::ActionsNotUnique);
}
}
/// Errors that result from incompatible strategy representation
///
/// If a strategy object passed to [Game::from_named] doesn't match the games information and
/// action structure, one of these errors will be returned.
#[derive(Debug, PartialEq, Eq)]
pub enum StratError {
/// Returned when the game doesn't have a specific infoset
InvalidInfoset,
/// Returned when the game doesn't have an action for an infoset
InvalidInfosetAction,
/// Returned when a probability for an action is negative, nan, or infinite
InvalidProbability,
/// Returned when every action in an infoset has zero probability
InvalidInfosetProbability,
}
#[cfg(test)]
mod strat_errors {
use crate::{Game, GameNode, IntoGameNode, PlayerNum, StratError};
struct Node(GameNode<Node>);
impl IntoGameNode for Node {
type PlayerInfo = &'static str;
type Action = &'static str;
type ChanceInfo = &'static str;
type Outcomes = Vec<(f64, Node)>;
type Actions = Vec<(&'static str, Node)>;
fn into_game_node(self) -> GameNode<Self> {
self.0
}
}
fn create_game() -> Game<&'static str, &'static str> {
let node = Node(GameNode::Player(
PlayerNum::One,
"x",
vec![(
"a",
Node(GameNode::Player(
PlayerNum::Two,
"z",
vec![
(
"b",
Node(GameNode::Player(
PlayerNum::One,
"y",
vec![
("c", Node(GameNode::Terminal(0.0))),
("d", Node(GameNode::Terminal(0.0))),
],
)),
),
("c", Node(GameNode::Terminal(0.0))),
],
)),
)],
));
Game::from_root(node).unwrap()
}
#[test]
fn invalid_infoset() {
let game = create_game();
let err = game
.from_named([vec![("a", vec![("b", 1.0)])], vec![]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfoset);
let err = game
.from_named_slow([vec![("a", vec![("b", 1.0)])], vec![]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfoset);
}
#[test]
fn invalid_infoset_action() {
let game = create_game();
let err = game
.from_named([vec![("x", vec![("b", 1.0)])], vec![]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfosetAction);
let err = game
.from_named_slow([vec![("x", vec![("b", 1.0)])], vec![]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfosetAction);
}
#[test]
fn invalid_probability() {
let game = create_game();
let err = game
.from_named([vec![("x", vec![("a", -1.0)])], vec![]])
.unwrap_err();
assert_eq!(err, StratError::InvalidProbability);
let err = game
.from_named_slow([vec![("x", vec![("a", -1.0)])], vec![]])
.unwrap_err();
assert_eq!(err, StratError::InvalidProbability);
}
#[test]
fn invalid_infoset_probability_normal() {
let game = create_game();
let err = game
.from_named([vec![("x", vec![("a", 1.0)])], vec![("z", vec![("c", 1.0)])]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfosetProbability);
let err = game
.from_named_slow([vec![("x", vec![("a", 1.0)])], vec![("z", vec![("c", 1.0)])]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfosetProbability);
}
#[test]
fn invalid_infoset_probability_single() {
let game = create_game();
let err = game
.from_named([vec![("y", vec![("d", 1.0)])], vec![("z", vec![("c", 1.0)])]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfosetProbability);
let err = game
.from_named_slow([vec![("y", vec![("d", 1.0)])], vec![("z", vec![("c", 1.0)])]])
.unwrap_err();
assert_eq!(err, StratError::InvalidInfosetProbability);
}
}