The Hexareversi Project

Two good project implementations

Two teams of students agreed to have their excellent projects displayed on the course webpage:

1. Othexo by Kevin Koh and Kiat Boon;
2. Hexareversi Team 46 by Li Yier;
3. Hexareversi Team 77 by Lu Si Hong and Ling Xiao Xiong Shaun.

Reversi

The Reversi game (also known as Othello) is a two player game played on a square 8 * 8 board with 64 positions. The players move alternately and try to get as many pieces of their colour as possible. They put a new piece next to existing ones and all pieces of the opposite colour which are between the new and an old of the own colour are turned into the own colour. A move must always be made the way that at least one piece is turned.

The game ends when the board is full or when no more legal move is possible. The winner is then the player who owns the largest number of pieces.

Hexareversi

The task of the project is to work on an existing program for Hexagonal Reversi and to improve it. The Hexagonal Reversi differs from the standard one in two aspects:

1. The players move on a hexagonal grid where where each field has six neighbours in place of eight.
2. The players have the right to pass; if both players pass one after the other, the game ends.

Your task

The goal of the project is to improve the existing implementation on http://www.comp.nus.edu.sg/~gem1501/year1314sem2/project/hexareversi.html with respect to the two following aspects:

1. Improve the user interface;
2. Provide a good playing algorithm;
3. Provide a tournament option where the computer plays two strategies against each other for 10 games.

You will be working in teams of two.

Your strategy will be assessed by playing against some default opponents, the three random opponents implemented and a Mystery Player of better playing strength.

The user interface

You are free to make your own interface from scratch or reuse and improve the basic one provided to you. For examples of the endless possibilites of HTML5, CSS3 and Javascript, you can for instance look at the Mozilla Developer Network's Demo Studio (this is for illustrative purposes only, you are not required to develop a professional-looking application!).

You can also extend the game the way you want as long as you keep a version of your playing algorithm which respects the rules we defined (so that you can enter the tournament).

The playing algorithm

In order to make the tournament possible, it is necessary to agree on a common interface so that your playing algorithm can be called, sent the current contents of the board and can return a move.

Each playing algorithm must be contained in an object (without entering into the details of Javascript, we can turn the YourPlayer function into an object), having a function called nextMove:

function YourPlayer(side) {
    this.nextMove = function(board) {

        // this is where the magic happens

        return move;
    };
}

At the creation time of the YourPlayer object instance, the side parameter receives 1 or -1, respectively for player X or player Y.

The board parameter is an array. The entries have the following indices:

            11    12    13    14    15

         21    22    23    24    25    26

      31    32    33    34    35    36    37

   41    42    43    44    45    46    47    48

51    52    53    54    55    56    57    58    59

   62    63    64    65    66    67    68    69

      73    74    75    76    77    78    79

         84    85    86    87    88    89

            95    96    97    98    99

The neighbours of a cell c are the cells with the indices c+1, c+10, c+11, c-1, c-10, c-11. For example, the cell 75 has the neighbours 64, 65, 74, 76, 85, 86 which are in the row immediately above, the same row and the row immediatly below.

 -11   -10
    \ /
-1 — c — +1
    / \
 +10   +11

The entries in the board contain either a 0 (when the cell is free), a +1 (when there is a piece of player X), a -1 (when there is a piece of player Y), or undefined (when it is an invalid coordinate).

Given a variable c containing a cell number, one can use a conditional statement of the form:

if (c in board) {
    statement;
}

to make sure that the statement command is only done when c is indeed a cell of the board.

The return value of nextMove() must be a number indicating in which position the algorithm puts its piece. It can return 0 to indicate that it passes its turn.

The tournament option

The tournament option should enable to compare two of the given strategies by letting them play 10 games against each other (each strategy plays 5 times as Player X and 5 times as Player Y). The plays need not to be displayed, but a result summarising the scores should be given. This result should contain the following information:

• Number of games won by Strategy 1;
• Number of games won by Strategy 2;
• Number of draws;
• Number of pieces obtained by Strategy 1 in all games summed up;
• Number of pieces obtained by Strategy 2 in all games summed up.

You can use this option to check how well your players play against the random players and you can also write your programs such that you can compare the strength of your strategy with that of a fellow team.

For being able to do the latter, your strategy should be in an extra js-file on your homepage, different from the file of your game, and it should be possible to include it into the games of other players in order to play against it. See Your Implementation below for details.

Strategies

There are three model players preimplemented in the file "randommove.js". These players can be described as follows:

• The player "Random" computes a list of all possible moves and chooses among them one by random, all moves have the same probability. It only passes if it cannot move.
• The player "Greedy Random" also computes a list of all possible moves, but it chooses a move with a probability proportional to the pieces it gains; that is, the more pieces of the opponent it turns, the higher is the probability to be taken. This is achieved by making a list where good moves have multiple entries and then by choosing by random one of the entries.
• The player "Position Random" has a table on which positions are in general bad or good. It then chooses a move according to the highest category of positions possible and if there are several of these, it does a tie break in a way similar to the "Greedy Random" player.

Your Implementation

• First a main file containing your project including everything except your strategy (player);
• Second a file with your playing strategy called "YourPlayer". This second file will in turnaments be included into the programs of other players. Therefore you should follow some conventions.
• Your strategy file should be on your homepage and all global variables and functions in it should start with your team number. For example, the team numbers of the random players are t96 ... t99; you can choose and reserve by email to Thomas Kister (kister@comp.nus.edu.sg) a team number from t00 through t95. Do not use in your main program any functions or variables starting with the team number of another team (except that you can use the functions of the random players). The competing players will, in turnaments against you, include your player into their file or vice versa to play the turnament (in the same way as the current version includes the random player and a default for YourPlayer in extra src-files).

Your Presentation

Assessment

• Quality of Presentation and Project Description Material on the Homepage; the material should tell what had been done and which ways had been chosen to meet certain objectives.
• Quality of the Project (Java Script Program and Webpage): How good is the user interface, the possibility to do tournaments and other features implemented; in the case that you implement features related to the project which go beyond the requirements, this will give extra marks.
• Performance of the playing strategy when playing against random players and the not yet revealed Mystery Player; this should assess how strong your player is.
• Note that we might also inspect the code to see how you have solved the programming task and might take the readability of the program and its documentation into account.

The total number of marks obtainable for the project is 10 (out of 100 overall marks for the course).

Please keep all the information on your homepage available. When you are ready, please send an email with your team number, the names of your team members, the url of your material (including the programs) to kister@comp.nus.edu.sg and fstephan@comp.nus.edu.sg; you can also include the material as attachment to the email in the case that you want to be sure that it reaches us.

Deadline: Wednesday 16 April 2014 24:00 hrs