Homeworlds move generation is active. Prepped for 0.2.1 release

Author: Perlkonig

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.2.1] - 2021-10-31
+
+### Added
+
+- Homeworlds now uses the expanded annotations feature of the renderer.
+- There is now a move generator for Homeworlds! It's not particularly efficient, but it appears to at least function.
+- A rudimentary AI has been added, but it's very uneven. The move tree for Homeworlds can balloon quickly with a lot of movement actions.
+
 ## [0.2.0] - 2021-10-29
 
 ### Added

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@abstractplay/gameslib",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "TypeScript implementations of the core Abstract Play games, intended to be wrapped by the front- and backends",
   "main": "build/index.js",
   "types": "build/index.d.ts",
@@ -47,6 +47,7 @@
     "ajv": "^6.12.6",
     "graphology": "^0.21.0",
     "graphology-shortest-path": "^1.4.1",
+    "js-combinatorics": "^1.5.4",
     "minmax-wt-alpha-beta-pruning": "^1.0.5",
     "rfdc": "^1.3.0"
   }

package.json

@@ -35,7 +35,7 @@ const gameRules = {
 
 export class BlamAI extends AIBase {
     /**
-     * The Blam AI prefers first of all having more players than anybody else.
+     * The Blam AI prefers first of all having more pieces than anybody else.
      * After that, it values score, then number of captured pieces.
      */
     public static evaluate(state: IBlamState): number {
@@ -51,15 +51,8 @@ export class BlamAI extends AIBase {
             stashcounts[k - 1] = v.reduce((a, b) => {return a + b;});
         });
 
-        // Calculate piece advantage compared with highest (or next highest) player
         const mystash = stashcounts[g.currplayer - 1];
-        delete stashcounts[g.currplayer - 1];
-        const maxstash = Math.max(...stashcounts);
-        const diff = mystash - maxstash;
-        if (Math.abs(diff) > 1) {
-            score += (diff * wtPieces)
-        }
-
+        score += mystash * wtPieces
         score += g.scores[g.currplayer - 1] * wtScore;
         score += g.caps[g.currplayer - 1] * wtCaps;
 

src/ais/blam.ts

@@ -0,0 +1,74 @@
+import { HomeworldsGame, IHomeworldsState } from "../games";
+import {minmax} from 'minmax-wt-alpha-beta-pruning';
+import { AIBase } from "./_base";
+import { IAIResult } from ".";
+
+const gameRules = {
+    listMoves (state: IHomeworldsState): string[] {
+        const g = new HomeworldsGame(state);
+        return g.moves();
+    },
+    nextState (state: IHomeworldsState, move: string): IHomeworldsState {
+        const g = new HomeworldsGame(state);
+        g.move(move);
+        return g.state();
+    },
+    terminalStateEval (state: IHomeworldsState): number|null {
+        const g = new HomeworldsGame(state);
+        // g.checkEOG();
+        if (! g.gameover) {
+            return null;
+        }
+        if (g.winner.includes(g.currplayer)) {
+            return Infinity;
+        } else {
+            return -Infinity;
+        }
+    }
+}
+
+export class HomeworldsAI extends AIBase {
+    /**
+     * The only thing the AI cares about is piece superiority.
+     * Larger pieces are preferred over smaller ones.
+     */
+    public static evaluate(state: IHomeworldsState): number {
+        let score = 0;
+        const wtLge = 2;
+        const wtMed = 1.5;
+        const wtSm = 1;
+
+        const g = new HomeworldsGame(state);
+        // Find all ships you own and add their value to your score
+        const myseat = g.player2seat();
+        for (const sys of g.systems) {
+            for (const ship of sys.ships) {
+                if (ship.owner === myseat) {
+                    switch (ship.size) {
+                        case 1:
+                            score += ship.size * wtSm;
+                            break;
+                        case 2:
+                            score += ship.size * wtMed;
+                            break;
+                        case 3:
+                            score += ship.size * wtLge;
+                            break;
+                        default:
+                            throw new Error("Unrecognized ship size. This should never happen.");
+                    }
+                }
+            }
+        }
+
+        return score;
+    }
+
+    public static findmove(state: IHomeworldsState, plies: number): string {
+        const result: IAIResult =  minmax(state, gameRules, HomeworldsAI.evaluate, plies);
+        if ( (result === undefined) || (! result.hasOwnProperty("bestMove")) || (result.bestMove === undefined) || (result.bestMove === null) ) {
+            throw new Error("No best move found. This should never happen.");
+        }
+        return result.bestMove;
+    }
+}

src/ais/homeworlds.ts

@@ -3,6 +3,7 @@ import { AmazonsAI } from "./amazons";
 import { BlamAI } from "./blam";
 import { CannonAI } from "./cannon";
 import { MchessAI } from "./mchess";
+import { HomeworldsAI } from "./homeworlds";
 
 export interface IAIResult {
     bestMove: string|null;
@@ -13,20 +14,22 @@ export interface IAI {
     findmove: (state: any, depth: number) => string;
 }
 
-export { AIBase, AmazonsAI, BlamAI, CannonAI, MchessAI };
+export { AIBase, AmazonsAI, BlamAI, CannonAI, MchessAI, HomeworldsAI };
 
 export const supportedGames: string[] = ["amazons"];
 export const fastGames: Map<string, number> = new Map([
     ["amazons", 1],
     ["blam", 3],
     ["cannon", 3],
-    ["mchess", 5]
+    ["mchess", 5],
+    ["homeworlds", 4]
 ]);
 export const slowGames: Map<string, number> = new Map([
     ["amazons", 2],
     ["blam", 5],
     ["cannon", 5],
-    ["mchess", 7]
+    ["mchess", 7],
+    ["homeworlds", 6]
 ]);
 
 export function AIFactory(game: string): AIBase|undefined {
@@ -39,6 +42,8 @@ export function AIFactory(game: string): AIBase|undefined {
             return new CannonAI();
         case "mchess":
             return new MchessAI();
+        case "homeworlds":
+            return new HomeworldsAI();
     }
     return;
 }