Editing Computer poker player (section)

== Artificial Intelligence ==
Like in the games of [[chess]], [[Go (game)]], and many other games, [[artificial intelligence]] systems beat even the best humans at poker.<ref> {{Cite web |last=Intagliata |first=Christopher |title=This Artificial Intelligence Learns like a Baby |url=https://www.scientificamerican.com/podcast/episode/this-artificial-intelligence-learns-like-a-widdle-baby/ |access-date=2023-05-17 |website=Scientific American |language=en}}</ref><ref> {{Cite journal |last1=Meta Fundamental AI Research Diplomacy Team (FAIR)† |last2=Bakhtin |first2=Anton |last3=Brown |first3=Noam |last4=Dinan |first4=Emily |last5=Farina |first5=Gabriele |last6=Flaherty |first6=Colin |last7=Fried |first7=Daniel |last8=Goff |first8=Andrew |last9=Gray |first9=Jonathan |last10=Hu |first10=Hengyuan |last11=Jacob |first11=Athul Paul |last12=Komeili |first12=Mojtaba |last13=Konath |first13=Karthik |last14=Kwon |first14=Minae |last15=Lerer |first15=Adam |date=2022-12-09 |title=Human-level play in the game of Diplomacy by combining language models with strategic reasoning |url=https://www.science.org/doi/10.1126/science.ade9097 |journal=Science |language=en |volume=378 |issue=6624 |pages=1067–1074 |doi=10.1126/science.ade9097 |pmid=36413172 |bibcode=2022Sci...378.1067M |s2cid=253759631 |issn=0036-8075|url-access=subscription }}</ref> Poker is a game of [[Perfect information|imperfect information]] (because some cards in play are concealed) thus making it harder for anyone (including a computer) to deduce the final outcome of the hand. Because of this lack of information, the computer's programmers used to have to implement systems based on the [[Bayes' theorem]], [[Nash equilibrium]], [[Monte Carlo simulation]] or [[Artificial neural network|neural network]]s, all of which are imperfect techniques. [[Pluribus (poker bot)|Pluribus]], however, perfected poker by only looking ahead a few moves to determine what action to take, rather than attempting to evaluate all moves until the end of the game.

Older AIs like PokerSnowie and [[Claudico]] were created by allowing the computer to determine the best possible strategy by letting it play itself an enormous number of times. For years, this was the approach to poker AI, as opposed to attempting to make a computer that plays like a human. This resulted in odd bet sizing and a much different strategy than humans are used to seeing.

Methods were first developed to approximate perfect poker strategy from the [[game theory]] perspective in the heads-up (two player) game, and then for the multi-player game. Perfect strategy has multiple meanings in this context.  From a game-theoretic optimal point of view, a perfect strategy is one that cannot expect to lose to any other player's strategy; however, optimal strategy can vary in the presence of sub-optimal players who have weaknesses that can be exploited. In this case, a perfect strategy is one that correctly or closely models those weaknesses and takes advantage of them to make a profit, such as those explained above.

AI broke through to superhuman performance in poker during the 2010s, with the following timeline. In 2015, computers solved heads-up limit hold'em via [[Cepheus (poker bot)|Cepheus]]. Around 2018, [[Libratus]] demonstrated superhuman ability in heads-up no-limit hold'em. In 2019, [[Pluribus (poker bot)|Pluribus]] (a newer version of Libratus)<ref> {{Cite web |last1=Magazine |first1=Smithsonian |last2=Solly |first2=Meilan |title=This Poker-Playing A.I. Knows When to Hold 'Em and When to Fold 'Em |url=https://www.smithsonianmag.com/smart-news/poker-playing-ai-knows-when-hold-em-when-fold-em-180972643/ |access-date=2023-05-17 |website=Smithsonian Magazine |language=en}}</ref> demonstrated superhuman ability at six-player no-limit hold'em, the most commonly played single variety of poker in the world.<ref> {{Cite web |title=Bet On The Bot: AI Beats The Professionals At 6-Player Texas Hold 'Em |website=[[NPR]] |url=https://www.npr.org/2019/07/11/740661470/bet-on-the-bot-ai-beats-the-professionals-at-6-player-texas-hold-em |access-date=2023-05-17}}</ref> In 2021, Microsoft released the older poker-playing program, Libratus, commercially, which then beat four professional poker players in a 20-day long poker competition at Rivers Casino.<ref>“AI’s Disruption Of The Strategy Gaming Space Proves That Machines Are Getting Smarter.” Forbes.
Annie Brown. Nov 10, 2021,04:42pm EST.</ref>