From b3d48c9924a2502ba7e93bafb0a8afcd096bec76 Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin@worthe-it.co.za>
Date: Sun, 11 Aug 2019 12:28:38 +0200
Subject: Replaced hashmaps with deterministic hashmaps

I'm not worried about ddos attacks here, and this also has better perf
for small keys.
---
 src/strategy/minimax.rs | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

(limited to 'src/strategy/minimax.rs')

diff --git a/src/strategy/minimax.rs b/src/strategy/minimax.rs
index b34d2f8..55abcec 100644
--- a/src/strategy/minimax.rs
+++ b/src/strategy/minimax.rs
@@ -2,8 +2,8 @@ use crate::command::{Action, Command};
 use crate::constants::*;
 use crate::game::{GameBoard, SimulationOutcome};
 
+use fnv::FnvHashMap;
 use std::cmp;
-use std::collections::HashMap;
 use std::ops::*;
 use time::{Duration, PreciseTime};
 
@@ -45,9 +45,9 @@ pub fn choose_move(
 ) -> Command {
     let mut root_node = Node {
         score_sum: ScoreSum::new(),
-        player_score_sums: [HashMap::new(), HashMap::new()],
+        player_score_sums: [FnvHashMap::default(), FnvHashMap::default()],
         unexplored: move_combos(state),
-        children: HashMap::new(),
+        children: FnvHashMap::default(),
     };
 
     while start_time.to(PreciseTime::now()) < max_time {
@@ -75,23 +75,33 @@ pub fn choose_move_with_normalized_perf(
 ) -> Command {
     let mut root_node = Node {
         score_sum: ScoreSum::new(),
-        player_score_sums: [HashMap::new(), HashMap::new()],
+        player_score_sums: [FnvHashMap::default(), FnvHashMap::default()],
         unexplored: move_combos(state),
-        children: HashMap::new(),
+        children: FnvHashMap::default(),
     };
 
     for _ in 0..iterations {
         let _ = expand_tree(&mut root_node, state.clone(), config);
     }
 
+    eprintln!("Number of simulations: {}", root_node.score_sum.visit_count);
+    for (command, score_sum) in &root_node.player_score_sums[player_index] {
+        eprintln!(
+            "{} = {} ({} visits)",
+            command,
+            score_sum.avg().val,
+            score_sum.visit_count
+        );
+    }
+
     best_player_move(&root_node, player_index)
 }
 
 pub struct Node {
     score_sum: ScoreSum,
-    player_score_sums: [HashMap<Command, ScoreSum>; 2],
+    player_score_sums: [FnvHashMap<Command, ScoreSum>; 2],
     unexplored: Vec<[Command; 2]>,
-    children: HashMap<[Command; 2], Node>,
+    children: FnvHashMap<[Command; 2], Node>,
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
@@ -177,9 +187,9 @@ fn expand_tree(node: &mut Node, mut state: GameBoard, config: &ScoreConfig) -> S
 
         let new_node = Node {
             score_sum: ScoreSum::with_initial(score),
-            player_score_sums: [HashMap::new(), HashMap::new()],
+            player_score_sums: [FnvHashMap::default(), FnvHashMap::default()],
             unexplored,
-            children: HashMap::new(),
+            children: FnvHashMap::default(),
         };
         node.children.insert(commands, new_node);
         update(node, commands, score);
@@ -243,6 +253,7 @@ fn score(state: &GameBoard, config: &ScoreConfig) -> Score {
     let snowballs = state.players[0].snowballs() as f32 - state.players[1].snowballs() as f32;
     let bombs = state.players[0].bombs() as f32 - state.players[1].bombs() as f32;
 
+    // TODO: None of these attributes give any signal early on.
     // TODO: Try adding new features here. Something about board position?
     Score {
         val: max_health * config.max_health_weight
-- 
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