OpenLoop: first test passing for the new player

src/ai/OpenLoopMctsPlayer.js

@@ -22,7 +22,7 @@ export class OpenLoopMctsPlayer {
     }
 
     /**
-     * @param {InteractiveGame} game
+     * @param {Game} game
      * @returns {Command[]}
      */
     decideMove(game) {
@@ -79,9 +79,9 @@ export class OpenLoopMctsPlayer {
     _select(game, node) {
         while (!game.isTerminal()) {
             if (node.childrenSize === 0) {
-                return node.bestUctChild(this.args.expansionFactor, this.args.samplingExplorationChance);
+                return node.bestUctChild(game, this.args.expansionFactor);
             } else {
-                [game, node] = node.bestUctChild(this.args.expansionFactor, this.args.samplingExplorationChance);
+                [game, node] = node.bestUctChild(game, this.args.expansionFactor);
             }
         }
         // game is terminal

src/ai/OpenLoopMctsPlayer.test.js

@@ -1,9 +1,25 @@
 import { fixedRandom, resetFixedRandom } from "../lib/random.js";
+import { Command } from "../model/commands/commands.js";
 import makeGame from "../model/game.js";
 import { TwoOnTwoMeleeScenario } from "../model/scenarios.js";
 import { OpenLoopMctsPlayer } from "./OpenLoopMctsPlayer.js";
 
 describe('OpenLoopMctsPlayer', () => {
+    test('decideMove returns a valid move', () => {
+        const game = makeGame(new TwoOnTwoMeleeScenario());
+        const player = new OpenLoopMctsPlayer({
+            expansionFactor: 2.1415,
+            playoutIterations: 20,
+            iterations: 1,
+            logfunction: () => {},
+        });
+
+        const move = player.decideMove(game);
+
+        expect(move).toBeInstanceOf(Array);
+        move.forEach(command => expect(command).toBeInstanceOf(Command));
+    });
+
     const originalRandom = Math.random;
     beforeEach(() => {
         resetFixedRandom();
@@ -23,7 +39,7 @@ describe('OpenLoopMctsPlayer', () => {
     test('2 on 2', () => {
         const game = makeGame(new TwoOnTwoMeleeScenario());
 
-        const root = player.search(game, 1);
+        const root = player.search(game, 2);
 
         const rootAsString = root.toString();
         console.log(rootAsString);

src/ai/OpenLoopNode.js

@@ -28,12 +28,11 @@ export default class OpenLoopNode {
      */
     bestUctChild(game, expansionFactor= 2.4142) {
         ensure(this.side === game.currentSide, `The node's side ${this.side} must be the same as the game's current side ${game.currentSide}}`);
-        ensure(this.visits > 0, "The node must have been visited at least once");
 
         let bestChild = undefined;
         let bestScore = -Infinity;
         let bestClone = undefined;
-        const logOfThisVisits = Math.log(this.visits);
+        const logOfThisVisits = this.visits === 0 ? 0 : Math.log(this.visits);
         for (const command of randomShuffleArray(game.validCommands())) {
             const clone = game.clone();
             clone.executeCommand(command);
@@ -126,6 +125,10 @@ export default class OpenLoopNode {
         return this.#children.size;
     }
 
+    get children() {
+        return this.#children.values();
+    }
+
     /**
      * @param {Command} command
      * @returns {OpenLoopNode}
@@ -147,12 +150,16 @@ export default class OpenLoopNode {
     shape() {
         const result = [];
 
+        /**
+         * @param {OpenLoopNode} node
+         * @param {number} level
+         */
         function traverse(node, level) {
             if (!result[level]) {
                 result[level] = 0;
             }
             result[level]++;
-            for (const child of node.children) {
+            for (const [__, child] of node.children) {
                 traverse(child, level + 1);
             }
         }

src/ai/__snapshots__/OpenLoopMctsPlayer.test.js.snap

@@ -1,6 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`OpenLoopMctsPlayer 2 on 2 1`] = `
-"undefined -> 0/0: Side: Roman -> 0
+"undefined -> -1/2: Side: Roman -> 2
+ PlayCard(Order Three Units Left) -> -1/1: Side: Roman -> 0
+ PlayCard(Order Heavy Troops) -> 0/1: Side: Roman -> 1
+  End phase -> 0/1: Side: Roman -> 0
 "
 `;