Gomoku

Author: Yucheng Jiang - [email protected]

Gomoku (five-in-a-row) game featuring a powerful Alpha-beta pruning algorithm written in C++. Download the latest release executable file here.

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Table of Contents

• Installation
• Algorithm
• Contributing

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Installation

Clone

• Clone this repo to your local machine using https://github.com/CS126SP20/final-project-Yucheng-Jiang.git

Setup

Clone imGUI from https://github.com/simongeilfus/Cinder-ImGui and save the file under {cinder root file path}\blocks\imGUI

Now you are ready to run the program

If want to make some changes to the program, here are a few things that can be adjusted

Change game rule in \include\Game.h

class Game {
 public:
  // standard board size.
  static const int BOARD_SIZE = 19;
  // number of consecutive stone needed to win
  static const int WINNING_THRESHOLD = 5;
  // current winner
  Stone mWinner;
  ....
      
 public:
    .....
 private:
    .....
}

Make changes to BOARD_SIZE to adjust board size. Note that currently only support board size from 5 to 19 (inclusive). Also the user interface not yet support board size change.

Make changes to WINNING_THRESHOLD to adjust winning condition for the game. Adjust to 3 to make the game to become TIC_TAC_TOE.

Change Alpha-Beta pruning algorithm parameters in \include\Minimax.h

// we only care about 7 consecutive stones on the board
// each stone convert to 2 bit number, 00 , 01, or 11
// therefore, max size would be 2^(7 * 2) = 0x3fff
static const int BIT_DATA_LENGTH = 14;
static const int BIT_DATA_SIZE = 0x3fff;  // NOLINT
// search for empty grid within 2 unit of the occupied grid.
// increase this value could slightly increase win rate
// but exponentially decrease efficiency
static const int SEARCH_RANGE = 2;
// default search depth. Increase depth will significantly increase win rate
// while factorial increase time needed to finish computation
static const int SEARCH_DEPTH = 3;
// multiple-thread number, default set to be 4. No harm to be higher.
static const int THREAD_NUM = 4;

enum PatternType{...}
struct Pattern{...}
struct ScoreCache{...}
class CandidatePosition{...}
class AlphaBetaAlgorithm{...}
struct MinimaxThreadParagm{...}

Make changes to SEARCH_RANGE will change the empty grid within N grid of the occupied position. Increase this value will significantly increase running time will have slightly higher winning rate.

Make changes to SEARCH_DEPTH will change recursion depth in minimax algorithm. Increase this value will significantly increase both winning rate and running time. Ideally, the algorithm becomes unbeatably when the depth is greater than 5.

Make changes to THREAD_NUM will change number of thread used when MiniMaxMT strategy is called. No harm to change the value larger than 4.

Customized player strategy, here are a few things that need to be changed

First add your strategy name in \apps\my_app.cc

void MyApp::setup() {
// set random seed for current game.
  ......
  // select black side player (initialized to be human player)
  mBlackSelection = 0;
  mBlackPlayers = {"Player", "Random", "MinMax", "MinMaxMT"};
  // select white side player (initialized to be minimax auto player)
  mWhiteSelection = 3;
  mWhitePlayers = {"Player", "Random", "MinMax", "MinMaxMT"};
  // set up control panel (to select player type, restart/exit game)
  ......
}

Add or delete black and/or white player strategy in array mBlackPlayers and/or mWhitePlayers. Also change default strategy by changing index mBlackSelection and/or mWhiteSelection

Secondly, write your strategy in a new file. Place header file under \include folder and source file under \src folder.

Finally, add control logic in \apps\my_app.cc

void MyApp::update() {
  // if currently does not need to flash latest stone
  if (mFlashCount == 0) {
    .....
    switch (game.GetRole()) {
      case Stone::BLACK:
        // given auto play based on player type.
        switch (mBlackSelection) {
          case 0:  // human player doesn't need auto play
            break;
          case 1:  // random
            ....
            break;
          case 2:  // MinMax
            ...
            break;
          case 3:  // MinMax multiple thread
            .....
            break;
          case 4: // your straegy here
            .....
            break;
        }
        break;
      case Stone::WHITE:
        // same as case Stone::BLACK above.
    }
  }
}

Add your call to your strategy in switch logic as shown above.

Now run the app, you can choose your strategy on the right side of the screen.

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Algorithm

1. Call IniScoreTable to set up score table for GoMoKu
2. Call AlphabetaGo or AlphabetaGoMT to get best move
   • Evaluate score for current board by calling SchoreChessToCache
   • For every available position (empty grid within SEARCH_RANGE)
     • try temporary move in this position
     • call MiniMax recursive function to retrieve score for this position
       • if reach terminal state (depth equal to 0 or has winner), call EvaluateBoard
         • for every grid that has temporary move, evaluate the move (ScoreChessPointtoCache)
         • retrieve score for the whole board (ScoreChess)
         • final score equals my score minus opponent score
       • if current player is max player
         • set best value to negative infinity
         • for all available position (empty grid within SEARCH_RANGE) sorted by point score (SearchCandidatePosition)
           • try move, call minimax to retrieve score for this point, and reset position to empty
           • update best value, and do beta pruning
       • if current player is not max player
         • set best value to positive infinity
         • for all available position (empty grid within SEARCH_RANGE) sorted by point score (SearchCandidatePosition)
           • try move, call minimax to retrieve score for this point, and reset position to empty
           • update best value, and do alpha pruning
     • reset current position back to empty
   • Return position with highest value

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Contributing

Step 1

• Option 1

  • 🍴 Fork this repo!

• Option 2

  • 👯 Clone this repo to your local machine using https://github.com/CS126SP20/final-project-Yucheng-Jiang.git

Step 2

• HACK AWAY! 🔨🔨🔨

Step 3

• 🔃 pull request not yet supported

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