The general public remembers Deep Blue, a seasoned opponent and ultimately executioner of Garry Kasparov. The poker community remembers the names of Polaris, who in 2007 had made a mixed copy after a series of duels against Phil Laak and Ali Eslami, and of Tartanian7, which hit the headlines a few months ago after Card Player published an interview with its creator.
The newcomer is called Cepheus. Like its predecessor Polaris, this poker-loving computer program owes its existence to researchers at the University of Alberta. And like Tartanian7, he recently had the honors of the international (Science, The Guardian, The Washington Post) and French (Le Parisien) press because of his mastery at the tables of Limit Hold’em Heads Up.
Talking about mastery even seems below the truth since according to its developers, Cepheus simply cannot be beaten in the long term. It is also this invincibility which allows them to say that Limit Hold’em Heads Up is “solved”. A status that the variant now shares with many other long-standing “resolved” games, such as checkers or the power of 4, Le Parisien specifies.
But for a game with imperfect information, this is indeed a great first and therefore a real leap forward for artificial intelligence. A leap that its creators attribute first to recent advances in algorithms, then to a supercomputer job whose figures make you dizzy: two months of training, 4,000 processors running simultaneously, and six billion hands considered per second.
As for the final stages of his progress, Cepheus owes them to astronomical amounts of disputed hands … against himself. Like any player who wants to improve, the program has looked at his history, analyzing his moves and correcting his little habits over time. Today he would have become “so close to perfect that after playing the equivalent of a lifetime of poker against him, that is, sixty million hands, you can’t tell the difference“.
If you still doubt it, go to this page to form your own opinion. Tired of solo games, Cepheus indeed welcomes to his table anyone who wishes to compete with him. Before perhaps one day trying their hand at No Limit or multiway play, formats which, due to their complexity, should keep their share of mystery in the eyes of artificial intelligence for a long time to come.