The Dresden server, plus rewriting Othello

I recently found that the Dresden server is up and capable of hosting round-robin matches again. (It doesn't have a hostname at the moment, and I don't want to link directly to an IP address, so reach it via the first link on this page.)

The Dresden server is different from Tiltyard in that it has a wider variety of games, somewhat less curated than Tiltyard's selection in terms of the GDL and ease of processing the game descriptions. Unlike Tiltyard, Dresden will have gamers play pretty much every game it has.

Rewriting checkers

I had a suspicion a while back that some GDL games were poorly written in terms of performance, and could be improved upon. Recently, I was looking over the checkers rules and decided they would be a good test case for this treatment.

A quick guide to GDL terminology

I'm writing another post which is pretty heavy on the GDL terminology. I may not have the time to make every such post readable for someone who doesn't know a sentence from a term. Hopefully, this will also be of use to anyone trying to sort out the Gdl classes in GGP-Base.

What is a propnet?

Propositional networks, or propnets, are an alternative way of expressing the rules of a game, covered in Stanford's CS 227B course.

Writing a game with GDL: Sim

I described the Game Description Language in an earlier post, but didn't show an example of a complete game description in practice. Today, I'll write a new game and record the process I use to make sure it's correct.

The game I'll write today is Sim, a simple graph coloring game I found on Wikipedia.

The Game Description Language

The Game Description Language is tasked with being able to describe a wide variety of games: chess, checkers, connect four, the iterated Prisoner's Dilemma, and so on. It requires only that the games have a few particular properties:

What is GGP?

This blog is aimed mainly at those who are already somewhat familiar with General Game Playing, but for those who are not, an explanation:

General Game Playing is an artificial intelligence (AI) research problem in which computer programs play games against each other. It differs from other similar research problems in that a program must be able to play any game -- rules are specified when the game starts, much too late for the programmer to intervene. This means that techniques used by the AI must be general, not limited to a single game. The intelligence is in the program, not the programmer.

A GGP match is run by a game server, which contacts the game players. At the beginning of the match, the players receive the rules of the game, their role assignment (e.g. white or black), and how much time they'll have to make their moves. Game rules are specified in the Game Description Language, a highly flexible way of expressing games using mathematical logic. Games may have any number of players; may be competitive, cooperative, or anywhere in between; can have arbitrary notions of game state; and, though they must be turn-based, may have simultaneous actions.

An International General Game Playing Competition is held yearly at major AI conferences. In the past two years, other conferences have hosted additional tournaments, all allowing remote competition. Continuously running game servers (Tiltyard and the Dresden server) also offer the chance for programmers to test their gamers' skills against each other.

Some universities are also offering courses in GGP. Stanford's version, taught by Mike Genesereth, the creator of the GGP project and Game Description Language, will be offered on Coursera in April 2013.