commit old stuff

src/elo.rs

@@ -2,14 +2,14 @@ use crate::{
     agent::{Agent, RandomAgent},
     complexagent::ComplexAgent,
     game_inner::GameInner,
-    logic::{ChildrenEvalMethod, FutureMoveConfig},
+    logic::{ChildrenEvalMethod, FutureMoveConfig, FutureMoves},
     repr::{Board, Piece, Winner},
 };
-use indicatif::{ParallelProgressIterator, ProgressBar, ProgressDrawTarget, ProgressStyle};
+use indicatif::{ProgressBar, ProgressStyle};
 use rand::seq::SliceRandom;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use skillratings::{
-    elo::{elo, EloConfig, EloRating},
+    glicko2::{confidence_interval, glicko2, Glicko2Rating},
     Outcomes, Rating,
 };
 use std::num::NonZero;
@@ -18,18 +18,19 @@ type AgentMaker = Box<dyn Fn(Piece) -> Box<dyn Agent>>;
 
 #[allow(dead_code)]
 pub fn run() {
+    let total_memory = 30_000_000_000; // 30 GB
+    let num_threads = std::thread::available_parallelism()
+        .map(NonZero::get)
+        .expect("unable to get number of threads");
+    let mem_per_thread = total_memory / num_threads;
+
     let fmv_base = FutureMoveConfig {
-        max_depth: 20,
-        min_arena_depth: 14,
-        top_k_children: 2,
-        up_to_minus: 10,
-        max_arena_size: usize::MAX,
-        do_prune: false,
+        max_arena_size: mem_per_thread / FutureMoves::ARENA_ENTRY_SIZE,
         print: false,
-        children_eval_method: Default::default(),
+        ..Default::default()
     };
 
-    let configs = [6]
+    let configs = [2, 3, 4, 5, 6, 7, 8]
         .into_iter()
         .map(move |d| FutureMoveConfig {
             max_depth: d,
@@ -71,7 +72,7 @@ pub fn run() {
             .to_vec()
         })
         .flat_map(move |prev_c| {
-            [ChildrenEvalMethod::MinMax, ChildrenEvalMethod::MinMaxFlat].map(move |method| {
+            [ChildrenEvalMethod::MinMax, ChildrenEvalMethod::MinMaxProb].map(move |method| {
                 FutureMoveConfig {
                     children_eval_method: method,
                     ..prev_c
@@ -119,33 +120,45 @@ pub fn run() {
             )
         })
         .collect();
+
+    if false {
         vec.push((
             "RandomAgent".to_string(),
             Box::new(move |piece| Box::new(RandomAgent::new(piece))),
         ));
+    }
 
     let mut arena = PlayerArena::new(vec);
 
-    arena.prop_arena(100);
+    arena.prop_arena(500);
 
     println!("{}", arena);
 }
 
 pub struct PlayerArena {
     /// Name, Creator Function, Elo
-    players: Vec<(String, AgentMaker, EloRating)>,
+    players: Vec<(String, AgentMaker, Glicko2Rating)>,
 }
 
 impl std::fmt::Display for PlayerArena {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let mut players_i: Vec<usize> = (0..self.players.len()).collect();
-        players_i.sort_by_key(|&i| -(self.players[i].2.rating() * 100.0) as i64);
+
+        players_i.sort_by(|&a, &b| {
+            self.players[b]
+                .2
+                .rating()
+                .total_cmp(&self.players[a].2.rating())
+        });
 
         for i in players_i {
+            let conf_interval = confidence_interval(&self.players[i].2);
+
             writeln!(
                 f,
-                "({:.2}): {}",
+                "({:.2}[+/-{:.2}]): {}",
                 self.players[i].2.rating(),
+                conf_interval.1 - self.players[i].2.rating(),
                 self.players[i].0
             )?;
         }
@@ -159,9 +172,8 @@ impl PlayerArena {
         Self {
             players: players
                 .into_iter()
-                .zip([EloRating::new()].into_iter().cycle())
-                // flatten tuple
-                .map(|((a, b), c)| (a, b, c))
+                // All starting ratings should be the default
+                .map(|(a, b)| (a, b, Default::default()))
                 .collect(),
         }
     }
@@ -172,7 +184,10 @@ impl PlayerArena {
             .map(|&(i, j)| {
                 (
                     (i, j),
-                    Self::create_agents(&self.players[i].1, &self.players[j].1),
+                    (
+                        (self.players[i].1)(Piece::Black),
+                        (self.players[j].1)(Piece::White),
+                    ),
                 )
             })
             .collect::<Vec<_>>();
@@ -189,7 +204,6 @@ impl PlayerArena {
         // Spawn parallel processing in a dedicated thread
         let processing_thread = {
             let sender = sender.clone();
-            let term = term.clone();
 
             std::thread::spawn(move || {
                 rayon::ThreadPoolBuilder::new()
@@ -203,22 +217,6 @@ impl PlayerArena {
 
                 created_pairs
                     .into_par_iter()
-                    .progress_with({
-                        let a = ProgressBar::new(num as u64).with_style(
-                            ProgressStyle::with_template(
-                                "[{elapsed_precise}] {pos:>7}/{len:7} ETA: {eta}",
-                            )
-                            .expect("invalid ProgressStyle"),
-                        );
-                        a.set_draw_target(ProgressDrawTarget::term(term, 5));
-                        a
-                    })
-                    .progress_with_style(
-                        ProgressStyle::with_template(
-                            "[{elapsed_precise}] {pos:>7}/{len:7} ETA: {eta}",
-                        )
-                        .expect("invalid ProgressStyle"),
-                    )
                     .map(|((i, j), (p1, p2))| (i, j, Self::play_two_inner(p1, p2)))
                     .for_each(|(i, j, o)| {
                         sender.send((i, j, o)).expect("Failed to send result");
@@ -231,17 +229,29 @@ impl PlayerArena {
 
         // Process results on main thread as they arrive
         let mut received_num = 0;
+        let p = ProgressBar::new(num as u64).with_style(
+            ProgressStyle::with_template("[{elapsed_precise}] {pos:>7}/{len:7} ETA: {eta}")
+                .expect("invalid ProgressStyle"),
+        );
+
         while let Ok((i, j, o)) = receiver.recv() {
             self.process_outcome(i, j, &o);
-            received_num += 1;
 
-            term.clear_last_lines(self.players.len())
+            if received_num > 0 {
+                term.clear_last_lines(self.players.len() + 1)
                     .expect("unable to clear prev lines");
+            }
             term.write_str(format!("{}", self).as_str())
                 .expect("unable to write leaderboard");
 
+            received_num += 1;
+            p.inc(1);
+            // add extra newline after progressbar
+            println!();
+
             // break if all pairs were recieved
             if received_num == num {
+                drop(receiver);
                 break;
             }
         }
@@ -253,35 +263,25 @@ impl PlayerArena {
     }
 
     fn prop_arena(&mut self, n: usize) {
-        self.play(
-            &(0..self.players.len())
+        let mut games = (0..self.players.len())
             .flat_map(|i| {
                 (0..self.players.len())
                     .map(move |j| (i, j))
                     .filter(|(i, j)| i != j)
-                        .collect::<Vec<_>>()
             })
             .collect::<Vec<_>>()
-                .repeat(n),
-        );
+            .repeat(n);
+        games.shuffle(&mut rand::rng());
+        self.play(&games);
     }
 
     fn process_outcome(&mut self, player1: usize, player2: usize, outcome: &Outcomes) {
-        let (np1, np2) = elo(
+        (self.players[player1].2, self.players[player2].2) = glicko2(
             &self.players[player1].2,
             &self.players[player2].2,
             outcome,
-            &EloConfig::new(),
+            &Default::default(),
         );
-        self.players[player1].2 = np1;
-        self.players[player2].2 = np2;
-    }
-
-    fn create_agents(
-        player_1_fn: &AgentMaker,
-        player_2_fn: &AgentMaker,
-    ) -> (Box<dyn Agent>, Box<dyn Agent>) {
-        (player_1_fn(Piece::Black), player_2_fn(Piece::White))
     }
 
     fn play_two_inner(player_1: Box<dyn Agent>, player_2: Box<dyn Agent>) -> Outcomes {
@@ -289,7 +289,8 @@ impl PlayerArena {
             player_1,
             player_2,
             false,
-            Board::random(rand::random_range(3..=7)),
+            // Board::random(rand::random_range(4..=15)),
+            Board::STARTING_POSITION,
         )
         .expect("unable to create game")
         .loop_until_result();

src/logic/board_value.rs

@@ -33,10 +33,4 @@ impl BoardValueMap {
         ];
         Self(PosMap::from(POSITION_VALUES))
     }
-
-    pub const fn flat() -> Self {
-        Self(PosMap::from(
-            [[1; Board::SIZE as usize]; Board::SIZE as usize],
-        ))
-    }
 }

src/logic/future_moves.rs

@@ -1,3 +1,4 @@
+use super::r#move::{MoveCoord, MoveValueConfig};
 use crate::{
     logic::r#move::Move,
     repr::{Board, Piece, Winner},
@@ -15,8 +16,6 @@ use std::{
     },
 };
 
-use super::r#move::MoveCoord;
-
 #[derive(Allocative)]
 pub struct FutureMoves {
     /// Arena containing all [`Move`]
@@ -25,9 +24,6 @@ pub struct FutureMoves {
     /// Index of the [`Move`] tree's root node
     current_root: Option<usize>,
 
-    /// Current generated depth of the Arena
-    current_depth: usize,
-
     /// Color w.r.t
     agent_color: Piece,
 
@@ -38,7 +34,7 @@ pub struct FutureMoves {
     board: Board,
 }
 
-#[derive(Copy, Clone, Allocative)]
+#[derive(Copy, Clone, Allocative, Default)]
 pub struct FutureMoveConfig {
     /// Max depth of that we should try and traverse
     pub max_depth: usize,
@@ -91,24 +87,15 @@ impl std::fmt::Display for FutureMoveConfig {
     }
 }
 
-#[derive(Debug, Clone, Copy, Allocative)]
+#[derive(Debug, Clone, Copy, Allocative, Default)]
 #[allow(dead_code)]
 pub enum ChildrenEvalMethod {
-    Average,
-    AverageDivDepth,
-
-    MinAvgDivDepth,
-
     /// Best so far?
+    // #[default]
     MinMax,
 
-    MinMaxFlat,
-}
-
-impl Default for ChildrenEvalMethod {
-    fn default() -> Self {
-        Self::MinMax
-    }
+    #[default]
+    MinMaxProb,
 }
 
 impl FutureMoves {
@@ -116,13 +103,15 @@ impl FutureMoves {
         Self {
             arena: Vec::new(),
             current_root: None,
-            current_depth: 0,
             agent_color,
             config,
             board: Board::new(),
         }
     }
 
+    pub const ARENA_ENTRY_SIZE: usize =
+        size_of::<Move>() + size_of::<usize>() * (Board::AREA.0 as usize / 4);
+
     /// Return the length of the Arena
     pub fn arena_len(&self) -> usize {
         self.arena.len()
@@ -145,39 +134,34 @@ impl FutureMoves {
         indexes
     }
 
-    /// Find the current depth of the arena by
-    /// looking at leaf moves and finding the smallest value
-    fn determine_current_depth(&self) -> Option<usize> {
+    /// Return the current depth of the tree
+    fn current_depth(&self) -> usize {
         // leaf_moves is sorted from min to max depth
-        self.leaf_moves().first().map(|&i| self.depth_of(i))
+        self.leaf_moves()
+            .first()
+            .map(|&i| self.depth_of(i))
+            .unwrap_or(0) // handle empty trees
     }
 
     /// Generate children for all children of `nodes`
     /// only `pub` for the sake of benchmarking
     pub fn extend_layers(&mut self) {
-        // recover from partial tree extention
-        if let Some(current_depth) = self.determine_current_depth() {
-            self.current_depth = current_depth;
-        }
+        let mut leafs = self.leaf_moves().into_iter().collect::<Vec<usize>>();
 
-        for _ in self.current_depth..self.config.max_depth {
+        for _ in self.current_depth()..self.config.max_depth {
             let pstyle_inner = if cfg!(test) || !self.config.print {
                 ""
             } else {
                 &format!(
                     "Generating children (depth: {}/{}): ({{pos}}/{{len}}) {{per_sec}}",
-                    self.current_depth + 1,
+                    self.current_depth() + 1,
                     self.config.max_depth
                 )
             };
 
             let allowed_size = self.config.max_arena_size - self.arena.len();
             let curr_size = Arc::new(AtomicUsize::new(0));
-            let got = self
-                .leaf_moves()
-                .into_iter()
-                .filter(|&i| self.depth_of(i) == self.current_depth)
-                .collect::<Vec<usize>>()
+            leafs = leafs
                 .into_par_iter()
                 .progress_with_style(ProgressStyle::with_template(pstyle_inner).unwrap())
                 .map(|parent_idx| (parent_idx, self.generate_children_raw(parent_idx)))
@@ -189,21 +173,22 @@ impl FutureMoves {
                         true
                     }
                 })
-                .collect::<Vec<(usize, Vec<Move>)>>();
-
-            // get total # of generated boards
-            let got_len = curr_size.load(Ordering::Acquire);
-
-            got.into_iter().for_each(|(parent_idx, moves)| {
+                .collect::<Vec<(usize, Vec<Move>)>>()
+                .into_iter()
+                .flat_map(|(parent_idx, moves)| {
                     let start_idx = self.arena.len();
                     self.arena.extend(moves);
 
                     let new_indices = start_idx..self.arena.len();
-                self.arena[parent_idx].children.extend(new_indices);
-            });
+                    self.arena[parent_idx].children.extend(new_indices.clone());
+                    new_indices
+                })
+                .collect();
+
+            // get total # of generated boards
+            let got_len = curr_size.load(Ordering::Acquire);
 
             self.prune_bad_children();
-            self.current_depth += 1;
             if got_len == allowed_size {
                 // arena has hit the upper limit of size permitted
                 break;
@@ -228,16 +213,7 @@ impl FutureMoves {
     }
 
     fn create_move(&self, coord: MoveCoord, board: Board, color: Piece) -> Move {
-        Move::new(
-            coord,
-            board,
-            color,
-            self.agent_color,
-            !matches!(
-                self.config.children_eval_method,
-                ChildrenEvalMethod::MinMaxFlat
-            ),
-        )
+        Move::new(coord, board, color, self.agent_color, MoveValueConfig {})
     }
 
     fn generate_children_raw(&self, parent_idx: usize) -> Vec<Move> {
@@ -313,64 +289,44 @@ impl FutureMoves {
         let by_depth_vec = self.by_depth(indexes);
 
         // reversed so we build up the value of the closest (in time) moves from the future
-        for (depth, nodes) in by_depth_vec.into_iter().rev() {
+        for (_depth, nodes) in by_depth_vec.into_iter().rev() {
             for idx in nodes {
                 let children_values = self.arena[idx]
                     .children
                     .iter()
                     .map(|&child| self.arena[child].value)
                     .collect::<Vec<_>>();
-
-                let children_value = match self.config.children_eval_method {
-                    ChildrenEvalMethod::Average => children_values
-                        .into_iter()
-                        .sum::<i32>()
-                        .checked_div(self.arena[idx].children.len() as i32),
-
-                    ChildrenEvalMethod::AverageDivDepth => children_values
-                        .into_iter()
-                        .sum::<i32>()
-                        .checked_div(self.arena[idx].children.len() as i32)
-                        .and_then(|x| x.checked_div(depth as i32)),
-                    ChildrenEvalMethod::MinAvgDivDepth => {
-                        if self.arena[idx].color == self.agent_color {
+                let child_value = if self.arena[idx].color == self.agent_color {
                     // get best (for the adversary) enemy play
                     // this assumes the adversary is playing optimally
 
-                            children_values.into_iter().min()
+                    children_values.iter().min()
                 } else {
-                            children_values
-                                .into_iter()
-                                .sum::<i32>()
-                                .checked_div(self.arena[idx].children.len() as i32)
-                                .and_then(|x| x.checked_div(depth as i32))
-                        }
+                    children_values.iter().max()
                 }
+                .cloned()
+                .unwrap_or(Default::default());
+                self.arena[idx].value = self.arena[idx].self_value;
 
-                    ChildrenEvalMethod::MinMax | ChildrenEvalMethod::MinMaxFlat => {
-                        if self.arena[idx].color == self.agent_color {
-                            // get best (for the adversary) enemy play
-                            // this assumes the adversary is playing optimally
+                match self.config.children_eval_method {
+                    ChildrenEvalMethod::MinMax => {
+                        self.arena[idx].value.value += child_value.value;
+                        self.arena[idx].value.set_state(child_value.state());
+                    }
+                    ChildrenEvalMethod::MinMaxProb => {
+                        self.arena[idx]
+                            .value
+                            .populate_self_from_children(&children_values);
 
-                            children_values.into_iter().min()
-                        } else {
-                            children_values.into_iter().max()
+                        self.arena[idx].value.value += child_value.value;
                     }
                 }
             }
-                .unwrap_or(0);
-
-                // we use `depth` and divided `self_value` by it, idk if this is worth it
-                // we should really setup some sort of ELO rating for each commit, playing them against
-                // each other or something, could be cool to benchmark these more subjective things, not
-                // just performance (cycles/time wise)
-                self.arena[idx].value = self.arena[idx].self_value as i32 + children_value;
-            }
         }
     }
 
     fn move_history(&self, idx: usize) -> Option<Vec<(MoveCoord, Piece)>> {
-        if let Some(root) = self.current_root {
+        self.current_root.and_then(|root| {
             let mut hist = Vec::new();
 
             let mut current = Some(idx);
@@ -390,34 +346,33 @@ impl FutureMoves {
             }
 
             Some(hist)
-        } else {
-            None
-        }
+        })
     }
 
     fn get_board_from_idx(&self, idx: usize) -> Option<Board> {
-        if let Some(hist) = self.move_history(idx) {
+        self.move_history(idx).and_then(|hist| {
             let mut board = self.board;
             for (m, c) in hist {
                 if let Some(m) = m {
-                    board.place(m, c).expect("move would not propegate");
+                    board.place(m, c).ok()?;
                 }
             }
             Some(board)
-        } else {
-            None
-        }
+        })
     }
 
     /// Return the best move which is a child of `self.current_root`
     pub fn best_move(&self) -> Option<MoveCoord> {
         self.current_root
-            .and_then(|x| {
-                self.arena[x]
+            .and_then(|x| match self.config.children_eval_method {
+                ChildrenEvalMethod::MinMax => self.arena[x]
                     .children
                     .iter()
-                    // this would be considered `minimax`
-                    .max_by_key(|&&idx| self.arena[idx].value)
+                    .max_by_key(|&&idx| self.arena[idx].value),
+                ChildrenEvalMethod::MinMaxProb => self.arena[x]
+                    .children
+                    .iter()
+                    .max_by_key(|&&idx| self.arena[idx].value),
             })
             .inspect(|&&x| {
                 assert_eq!(
@@ -461,7 +416,6 @@ impl FutureMoves {
     fn rebuild_from_board(&mut self, board: Board) {
         self.arena = vec![self.create_move(None, board, !self.agent_color)];
         self.current_root = Some(0);
-        self.current_depth = 0;
         self.board = board;
     }
 
@@ -469,7 +423,6 @@ impl FutureMoves {
         let board = self
             .get_board_from_idx(idx)
             .expect("unable to get board at idx");
-        self.current_depth -= self.depth_of(idx);
         self.current_root = Some(idx);
         self.board = board;
         self.refocus_tree();
@@ -521,7 +474,7 @@ impl FutureMoves {
     }
 
     fn prune_bad_children(&mut self) {
-        if self.current_depth < self.config.min_arena_depth || !self.config.do_prune {
+        if self.current_depth() < self.config.min_arena_depth || !self.config.do_prune {
             return;
         }
 
@@ -530,7 +483,7 @@ impl FutureMoves {
 
         for (depth, indexes) in self.by_depth(0..self.arena.len()) {
             // TODO! maybe update by_depth every iteration or something?
-            if depth > self.current_depth.saturating_sub(self.config.up_to_minus) {
+            if depth > self.current_depth().saturating_sub(self.config.up_to_minus) {
                 return;
             }
 
@@ -580,6 +533,8 @@ impl FutureMoves {
     /// Rebuilds the Arena based on `self.current_root`, prunes unrelated nodes
     fn refocus_tree(&mut self) {
         let Some(root) = self.current_root else {
+            // handle current_root being empty (clear arena and return)
+            self.arena.clear();
             return;
         };
 

src/logic/mod.rs

@@ -1,5 +1,6 @@
 mod board_value;
 mod future_moves;
 mod r#move;
+mod mvs;
 pub use future_moves::{ChildrenEvalMethod, FutureMoveConfig, FutureMoves};
 pub use r#move::MoveCoord;

src/logic/move.rs

@@ -1,4 +1,7 @@
-use super::board_value::BoardValueMap;
+use super::{
+    board_value::BoardValueMap,
+    mvs::{MVSGameState, MoveValueStats},
+};
 use crate::repr::{Board, CoordPair, Piece, Winner};
 use allocative::Allocative;
 
@@ -23,10 +26,10 @@ pub struct Move {
     pub children: Vec<usize>,
 
     /// Value of this move (including children)
-    pub value: i32,
+    pub value: MoveValueStats,
 
     /// What is the inherit value of this move (not including children)
-    pub self_value: i16,
+    pub self_value: MoveValueStats,
 
     /// Which color made a move on this move?
     pub color: Piece,
@@ -35,53 +38,47 @@ pub struct Move {
     pub is_trimmed: bool,
 }
 
+pub struct MoveValueConfig {}
+
 impl Move {
     pub fn new(
         coord: MoveCoord,
         board: Board,
         color: Piece,
         agent_color: Piece,
-        use_weighted_bvm: bool,
+        _: MoveValueConfig,
     ) -> Self {
         let mut m = Move {
             coord,
             winner: board.game_winner(),
             parent: None,
             children: Vec::new(),
-            value: i32::MIN,
+            value: Default::default(),
             color,
             is_trimmed: false,
-            self_value: 0,
+            self_value: Default::default(),
         };
-        m.self_value = m.compute_self_value(agent_color, &board, use_weighted_bvm);
+
+        // set wins/losses values appropriately
+        match m.winner {
+            Winner::Player(piece) => {
+                if piece == agent_color {
+                    m.self_value.set_state(Some(MVSGameState::Win));
+                } else {
+                    m.self_value.set_state(Some(MVSGameState::Loss));
+                }
+            }
+            Winner::Tie => {
+                m.self_value.set_state(Some(MVSGameState::Tie));
+            }
+            Winner::None => {}
+        }
+
+        m.self_value.value =
+            const { BoardValueMap::weighted() }.board_value(&board, agent_color) as i32;
         m
     }
 
-    fn compute_self_value(&self, agent_color: Piece, board: &Board, use_weighted_bvm: bool) -> i16 {
-        if self.winner == Winner::Player(!agent_color) {
-            // if this board results in the opponent winning, MAJORLY negatively weigh this move
-            // NOTE! this branch isn't completely deleted because if so, the bot wouldn't make a move.
-            // We shouldn't prune branches because we still need to always react to the opponent's moves
-            return i16::MIN + 1;
-        } else if self.winner == Winner::Player(agent_color) {
-            // results in a win for the agent
-            return i16::MAX - 1;
-        }
-        // else if self.winner == Winner::Tie {
-        //     // idk what a Tie should be valued?
-        //     return 0;
-        // }
-
-        // I guess ignore Ties here, don't give them an explicit value,
-        // because even in the case of ties, we want to have a higher score
-
-        match use_weighted_bvm {
-            true => const { BoardValueMap::weighted() },
-            false => const { BoardValueMap::flat() },
-        }
-        .board_value(board, agent_color)
-    }
-
     /// Sort children of the [`Move`] by their self_value in `arena`
     pub fn sort_children(&mut self, arena: &[Move]) {
         self.children.sort_by(|&a, &b| {

src/logic/mvs.rs

@@ -0,0 +1,164 @@
+use allocative::Allocative;
+use std::cmp::Ordering;
+
+#[derive(Clone, Copy, PartialEq, Eq, Allocative, Debug, PartialOrd, Ord)]
+pub enum MVSGameState {
+    Win = 1,
+    Tie = 0,
+    Loss = -1,
+}
+
+#[derive(Clone, Copy, Debug, Allocative, PartialEq, Eq, Default)]
+pub struct MoveValueStats {
+    state: Option<MVSGameState>,
+    wins: u16,
+    losses: u16,
+    ties: u16,
+    pub value: i32,
+}
+
+impl MoveValueStats {
+    #[cfg(test)]
+    pub fn new_from_outcomes(wins: u16, losses: u16, ties: u16) -> Self {
+        Self {
+            wins,
+            losses,
+            ties,
+            ..Default::default()
+        }
+    }
+
+    #[cfg(test)]
+    pub fn new_from_value(value: i32) -> Self {
+        Self {
+            value,
+            ..Default::default()
+        }
+    }
+
+    #[cfg(test)]
+    pub fn new_from_state(state: Option<MVSGameState>) -> Self {
+        Self {
+            state,
+            ..Default::default()
+        }
+    }
+
+    fn chance_win(&self) -> Option<f32> {
+        let sum = self.losses + self.wins + self.ties;
+        if 20 > sum {
+            return None;
+        }
+        Some(self.wins as f32 / sum as f32)
+    }
+
+    pub const fn set_state(&mut self, state: Option<MVSGameState>) {
+        self.state = state;
+    }
+
+    pub const fn state(&self) -> Option<MVSGameState> {
+        self.state
+    }
+
+    pub fn populate_self_from_children(&mut self, others: &[Self]) {
+        (self.wins, self.losses, self.ties) =
+            others.iter().fold((0, 0, 0), |(wins, losses, ties), x| {
+                (
+                    wins + x.wins + (x.state == Some(MVSGameState::Win)) as u16,
+                    losses + x.losses + (x.state == Some(MVSGameState::Loss)) as u16,
+                    ties + x.ties + (x.state == Some(MVSGameState::Tie)) as u16,
+                )
+            });
+    }
+}
+
+impl PartialOrd for MoveValueStats {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for MoveValueStats {
+    fn cmp(&self, other: &Self) -> Ordering {
+        if self.state.is_some() || other.state.is_some() {
+            return self.state.cmp(&other.state);
+        }
+
+        let (s_cw, o_cw) = (self.chance_win(), other.chance_win());
+        if s_cw.is_some() || o_cw.is_some() {
+            if s_cw > o_cw {
+                return Ordering::Greater;
+            } else if o_cw > s_cw {
+                return Ordering::Less;
+            }
+        }
+
+        self.value.cmp(&other.value)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn two_prob() {
+        let one = MoveValueStats::new_from_outcomes(100, 40, 0);
+
+        let two = MoveValueStats::new_from_outcomes(40, 60, 0);
+        assert!(one > two);
+    }
+
+    #[test]
+    fn one_prob_one_non() {
+        let one = MoveValueStats::new_from_outcomes(100, 4, 0);
+        let two = MoveValueStats::new_from_value(10);
+        assert!(one > two);
+    }
+
+    #[test]
+    fn one_prob_one_win() {
+        let one = MoveValueStats::new_from_outcomes(100, 4, 0);
+        let two = MoveValueStats::new_from_state(Some(MVSGameState::Win));
+        assert!(one < two);
+    }
+
+    #[test]
+    fn two_prob_zero() {
+        let one = MoveValueStats::new_from_outcomes(100, 0, 0);
+        let two = MoveValueStats::new_from_outcomes(0, 60, 0);
+        assert!(one > two);
+    }
+
+    #[test]
+    fn test_children_pop() {
+        let mut a = MoveValueStats::new_from_value(0);
+
+        let children = vec![
+            MoveValueStats::new_from_outcomes(1, 0, 0),
+            MoveValueStats::new_from_outcomes(0, 2, 0),
+            MoveValueStats::new_from_outcomes(0, 0, 3),
+        ];
+        a.populate_self_from_children(&children);
+        assert_eq!(a.wins, 1, "Wins should be 1");
+        assert_eq!(a.losses, 2, "Losses should be 2");
+        assert_eq!(a.ties, 3, "Ties should be 3");
+    }
+
+    #[test]
+    fn test_children_pop_state() {
+        let mut a = MoveValueStats::new_from_value(0);
+
+        let children = vec![
+            MoveValueStats::new_from_state(Some(MVSGameState::Win)),
+            MoveValueStats::new_from_state(Some(MVSGameState::Win)),
+            MoveValueStats::new_from_state(Some(MVSGameState::Loss)),
+            MoveValueStats::new_from_state(Some(MVSGameState::Tie)),
+            MoveValueStats::new_from_state(Some(MVSGameState::Tie)),
+        ];
+        a.populate_self_from_children(&children);
+        assert_eq!(a.wins, 2, "Wins should be 2");
+        assert_eq!(a.losses, 1, "Losses should be 1");
+        assert_eq!(a.ties, 2, "Ties should be 2");
+    }
+}

src/main.rs

@@ -39,7 +39,7 @@ fn main() {
         min_arena_depth: 14,
         top_k_children: 2,
         up_to_minus: 10,
-        max_arena_size: 200_000_000,
+        max_arena_size: 50_000_000,
         do_prune: false,
         print: true,
         children_eval_method: Default::default(),

src/repr/board.rs

@@ -3,10 +3,11 @@ use allocative::Allocative;
 use rand::seq::IteratorRandom;
 use std::{cmp::Ordering, fmt};
 
-#[derive(PartialEq, Eq, Copy, Clone, Debug, Allocative)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug, Allocative, Default)]
 pub enum Winner {
     Player(Piece),
     Tie,
+    #[default]
     None,
 }
 

src/repr/pos_map.rs

@@ -14,12 +14,12 @@ impl<T: Copy> PosMap<T> {
         Self(MaybeUninit::zeroed().assume_init())
     }
 
-    pub const fn from(v: [[T; Board::SIZE as usize]; Board::SIZE as usize]) -> Self {
+    pub const fn from(mut v: [[T; Board::SIZE as usize]; Board::SIZE as usize]) -> Self {
         let mut n = unsafe { Self::uninit() };
 
         const_for!(i in 0..Board::SIZE => {
             const_for!(j in 0..Board::SIZE => {
-                n.set(CoordPair::from_axes(i, j), v[i as usize][j as usize]);
+                std::mem::swap(n.get_mut(CoordPair::from_axes(i, j)), &mut v[i as usize][j as usize]);
             });
         });
         n