random game sampling and basic benchmark

src/game.rs

@@ -69,7 +69,7 @@ impl Default for Square {
 }
 
 
-#[derive(Debug, Default)]
+#[derive(Debug, Default, Copy, Clone)]
 pub struct Game {
     squares: [Square; 16],
     dice: EnumMap<Color, bool>,
@@ -77,12 +77,12 @@ pub struct Game {
 }
 
 impl Game {
-    fn new() -> Self {
+    pub fn new() -> Self {
         Self::default()
     }
 
     // new game with random starting positions
-    fn new_random() -> Self {
+    pub fn new_random() -> Self {
         let mut game = Self::default();
         let mut rng = rand::thread_rng();
         let mut dice = *&COLORS;
@@ -95,20 +95,46 @@ impl Game {
         game
     }
 
-    fn set_state(&mut self, squares: [Square; 16], dice: EnumMap<Color, bool>) {
-        self.squares = squares;
-        self.dice = dice;
-        for (i, square) in self.squares.iter().enumerate() {
-            if let Square::Camels(stack) = square {
-                for camel in stack.iter() {
-                    self.camels[*camel] = i
-                }
-            }
+    pub fn set_state(&mut self, camels: &[(Color, usize); 5], dice: &EnumMap<Color, bool>) {
+        for i in 0..16 {
+            self.squares[i] = match self.squares[i] {
+                Square::Camels(mut stack) => {
+                    stack.clear();
+                    Square::Camels(stack)
+                },
+                _ => Square::Camels(Stack::new())
+            };
+        }
+
+        for square in self.squares {
+            assert_eq!(square.assume_stack().len(), 0)
+        }
+
+        self.dice = *dice;
+        for &(color, sq) in camels {
+            self.squares[sq].assume_stack_mut().push(color);
+            self.camels[color] = sq;
         }
     }
 
+    pub fn get_state(&self) -> ([(Color, usize); 5], EnumMap<Color, bool>) {
+        let mut state = [(Color::Red, 0); 5];
+
+        let mut j = 0;
+        for (sq_idx, square) in self.squares.iter().enumerate() {
+            if let Square::Camels(stack) = square {
+                for camel in stack.iter() {
+                    state[j] = (*camel, sq_idx);
+                    j += 1;
+                }
+            }
+        }
+
+        (state, self.dice)
+    }
+
     // returns winner if there is one
-    fn advance(&mut self, die: Color, roll: usize) -> Option<Color> {
+    pub fn advance(&mut self, die: Color, roll: usize) -> Option<Color> {
         let src_sq = self.camels[die];
         let dst_sq = src_sq + roll;
         if dst_sq >= 16 {
@@ -171,7 +197,6 @@ impl Game {
         }
 
         (&mut leg_dice[..]).shuffle(&mut rng);
-
         for color in leg_dice.iter() {
             let roll = rng.gen_range(1..=3);
             if let Some(winner) = self.advance(*color, roll) {
@@ -189,8 +214,8 @@ impl Game {
         // we are now guaranteed to be at the start of a new leg,
         // so we don't need to check the dice state
         let mut rng = rand::thread_rng();
-        let roll_dist = Uniform::from(0..=3);
-        let mut dice = *&COLORS; // makes a copy of the constant
+        let roll_dist = Uniform::from(1..=3);
+        let mut dice = COLORS; // makes a copy of the constant
 
         loop {
             // easiest if we shuffle at the start of the leg
@@ -203,34 +228,53 @@ impl Game {
             }
         }
     }
+
+    pub fn project_outcomes(&self, count: usize) -> EnumMap<Color, usize> {
+        let (orig_camels, orig_dice) = self.get_state();
+        let mut projection = *self;
+
+        let mut scores: EnumMap<Color, usize> = EnumMap::default();
+        for i in 0..count {
+            let winner = projection.finish_game_random();
+            scores[winner] += 1;
+            projection.set_state(&orig_camels, &orig_dice);
+        }
+
+        scores
+    }
 }
 
 
 #[cfg(test)]
 mod test {
     use super::*;
+    use Color::*;
 
     #[test]
     fn test_advance() {
-        use Color::*;
         let mut game = Game::new();
         // all dice are false (not rolled) to start with
         assert_eq!(game.dice.values().any(|&v| v), false);
 
-        let mut squares = [Square::Camels(Default::default()); 16];
-        let one = squares[0].assume_stack_mut();
-        one.push(Blue);
-        one.push(Yellow);
-        squares[1].assume_stack_mut().push(Red);
-        let three = squares[2].assume_stack_mut();
-        three.push(Green);
-        three.push(Purple);
+        let camel_state = [
+            (Blue, 0),
+            (Yellow, 0),
+            (Red, 1),
+            (Green, 2),
+            (Purple, 2),
+        ];
+        game.set_state(&camel_state, &Default::default());
+        assert_eq!(game.squares[0].assume_stack(), &Stack::from([Blue, Yellow]));
+        assert_eq!(game.camels[Blue], 0);
+        assert_eq!(game.camels[Yellow], 0);
+        assert_eq!(game.squares[1].assume_stack(), &Stack::from([Red]));
+        assert_eq!(game.camels[Red], 1);
+        assert_eq!(game.squares[2].assume_stack(), &Stack::from([Green, Purple]));
+        assert_eq!(game.camels[Green], 2);
+        assert_eq!(game.camels[Purple], 2);
         //  BY, R, GP
 
-        game.set_state(squares, Default::default());
-
         game.advance(Yellow, 2);
-        println!("{:?}", game.camels);
         assert_eq!(game.dice[Yellow], true);
         assert_eq!(game.camels[Yellow], 2);
         assert_eq!(game.squares[2].assume_stack(), &Stack::from([Green, Purple, Yellow]));
@@ -247,5 +291,90 @@ mod test {
         // B, _, G, RPY
     }
 
+    #[test]
+    fn test_new_random() {
+        for _ in 0..100 {
+            let game = Game::new_random();
+            for (camel, i) in game.camels {
+                assert!(i < 3); // since we've only rolled the die once for each camel
+                let stack = game.squares[i].assume_stack();
+                assert!(stack[..].contains(&camel));
+            }
+        }
+    }
 
+    #[test]
+    fn test_finish_leg() {
+        let mut game = Game::new();
+        let camel_state = [
+            (Purple, 0),
+            (Blue, 0),
+            (Green, 1),
+            (Red, 1),
+            (Yellow, 2),
+        ];
+        game.set_state(&camel_state, &Default::default());
+        // PB, G, RY
+        game.advance(Green, 2);
+        // PB, _, RY, G
+        game.advance(Purple, 1);
+        // _, PB, RY, G
+
+        // since this is randomized, we should do it a bunch of times to make sure
+        for _ in 0..100 {
+            let mut projection = game; // copy?
+            assert_eq!(projection.squares[1].assume_stack(), &Stack::from([Purple, Blue]));
+            projection.finish_leg_random();
+            // since we already rolled Green, it can't have moved
+            assert_eq!(projection.camels[Green], 3);
+            // likewise purple
+            assert_eq!(projection.camels[Purple], 1);
+            // blue, red,and yellow, on the other hand, *must* have moved
+            assert_ne!(projection.camels[Blue], 1);
+            assert_ne!(projection.camels[Red], 2);
+            assert_ne!(projection.camels[Yellow], 2);
+        }
+    }
+
+    #[test]
+    fn test_finish_leg_winner() {
+        let mut game = Game::new();
+        let camel_state = [
+            (Green, 13),
+            (Red, 14),
+            (Purple, 14),
+            (Blue, 15),
+            (Yellow, 15),
+        ];
+        game.set_state(&camel_state, &Default::default());
+
+        // since there are no tiles involved, and multiple camels are on 15, there must be a winner
+        assert!(matches!(game.finish_leg_random(), Some(_)));
+    }
+
+    #[test]
+    fn test_project_outcomes() {
+        let mut game = Game::new();
+        let camel_state = [
+            (Blue, 1),
+            (Green, 2),
+            (Yellow, 2),
+            (Purple, 4),
+            (Red, 10),
+        ];
+        game.set_state(&camel_state, &Default::default());
+        // _, B, GY, _, P, _, _, _, _, _, R
+
+        let scores = game.project_outcomes(10_000);
+        let mut max = 0;
+        let mut winner = Blue; // just "anything that's not red"
+        for (color, score) in scores {
+            if score > max {
+                max = score;
+                winner = color;
+            }
+        }
+
+        assert_eq!(winner, Red);
+    }
 }

src/main.rs

@@ -1,7 +1,26 @@
+use std::time::Instant;
+
 mod stack;
 mod game;
 
+use game::Game;
+
 
 fn main() {
-    println!("Hello, world!");
+    let n_games = 10_000_000;
+
+    let start = Instant::now();
+    let game = Game::new_random();
+    let _scores = game.project_outcomes(n_games);
+    let end = Instant::now();
+
+    let elapsed = end.duration_since(start);
+    let secs = elapsed.as_secs();
+    let hundredths = elapsed.subsec_millis() / 10; // technically not accurate but good enough for now
+
+    let rate = (10_000_000 as f64) / elapsed.as_secs_f64();
+
+    println!("Test completed:");
+    println!("{n_games} in {secs}.{hundredths:02} seconds", );
+    println!("Games per second: {rate}");
 }

src/stack.rs

@@ -42,6 +42,10 @@ impl<T, const S: usize> Stack<T, S> {
             len: S,
         }
     }
+
+    pub fn into_inner(self) -> [T; S] {
+        self.data
+    }
 }