Poker aficionados have a new challenger in Cepheus - a computer program that is unbeatable in the two-player version of the Texas Hold 'Em Poker game.
Scientists from the University of Alberta, Canada, have designed a novel algorithm i.e. Cepheus, who has a near-perfect strategy for the game, which in turn makes the AI virtually unbeatable by human poker players at Texas Hold 'Em Poker. The statistical analysis backs the study and reveals that even if a human player plays against Cepheus for their lifetime, Cepheus will still emerge victorious or break even irrespective of how the game begins.
Cepheus is the brainchild of Michael Bowling, Michael Johanson, Neil Burch and Oskari Tammelin.
"We're not saying that it's guaranteed to win money on every single hand," says Bowling of The University of Alberta, who is also the co-author of the study. "What we're saying is that, in the long run, if you looked at all the hands that could happen and you averaged all of those, then the computer can't be losing, at a losing rate - it has to be either breaking even or winning."
Cepheus is touted as the first-ever computer program that is capable of playing a perfect game of poker sans any human help. It was only given the rules of the popular game's two-player version.
To brush up its poker playing skills, Cepheus trained for over two months using nearly 4000 CPUs each of which considered over 6 billion hands per second! And who did the computer program train against - itself! That's correct. Cepheus played over billion hands of poker and improved with each hand. Slowly it refined its playing tactics and became closer to the perfect solution.
Usually, in "perfect information" games like checkers or chess, the data needed for a player to make a decision is "stored on the board." On the other hand, poker is an "imperfect information game" and this factor makes the creation of a strategy for sure shot winning quite difficult.
So how does Cepheus work to achieve the near perfection? It's simple really, the program merely searches its pre-computed database of various game scenarios and zones in on the most optimal one that is befitting the situation. The computer basically does what it has not regretted in older games and deploys that strategy, an approach which results in "perfect play."
The common belief is that the dealer has the advantage in a game of Texas Hold 'Em Poker. Going second gives the dealer an advantage over their opponent even prior to the cards being dealt. This belief has been reinstated by Cepheus who demonstrated the advantage.
"We actually can now prove that the dealer has an advantage of what we call '88 millablinds' per game," says Michael Johanson. "That's .088 of a big blind per game."
"The breakthroughs behind this result are general algorithmic advances that make game-theoretic reasoning in large-scale models of any sort more tractable," says Bowling.
The study has been published in the journal Science. To challenge Cepheus at a game of Texas Hold 'Em Poker or query its strategy head here.
