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BRAINS VS. ARTIFICIAL INTELLIGENCE: CARNEGIE MELLON COMPUTER FACES POKER PROS IN EPIC NO-LIMIT TEXAS HOLD’EM COMPETITION
80,000 Hands Will Be Played in Two-week Contest at Rivers Casino in Pittsburgh
PITTSBURGH — April 24, 2015 — In a contest that echoes Deep Blue’s chess victory over Garry Kasparov and Watson beating two Jeopardy! champions, computer poker software developed at Carnegie Mellon University will challenge four of the world’s best professional poker players in a Heads-up No-limit Texas Hold’em competition beginning April 24 at Rivers Casino.
Over the course of two weeks, the CMU computer program, Claudico, will play 20,000 hands with each of the four poker pros in the two-player (Heads-up) game. The pros – Doug Polk, Dong Kim, Bjorn Li and Jason Les – will receive appearance fees derived from a prize purse of $100,000 donated by Microsoft Research and by Rivers Casino. The Carnegie Mellon scientists will compete for something more precious.
“Poker is now a benchmark for artificial intelligence research, just as chess once was,” said Tuomas Sandholm, a professor of computer science at Carnegie Mellon who has led development of Claudico. “It’s a game of exceeding complexity that requires a machine to make decisions based on incomplete and often misleading information, thanks to bluffing, slow play and other decoys. And to win, the machine has to out-smart its human opponents.
“Computing the world’s strongest strategies for this game was a major achievement – with the algorithms having future applications in business, military, cybersecurity and medical arenas,” added Sandholm.
Though an earlier version of the computer program, called Tartanian7, decisively won the Heads-up No-limit Texas Hold’em category of the Association for the Advancement of Artificial Intelligence’s Annual Computer Poker Competition last July, Sandholm said that doesn’t mean it is necessarily the equal of human players. Computers have demonstrated they can outplay humans at the simpler game of Heads-up Limit Texas Hold’em, he noted, but not the far more complicated no-limit version.
“I think it’s a 50-50 proposition,” he said of Claudico’s chances. “I think there’s a good chance we’ll lose this thing.”
“I imagine that the humans have an edge here,” Polk said, citing the extraordinary programming challenge for a no-limit game. “However, it is very difficult to determine an outcome with any sort of stability, as I do not know what I am going to be up against.”
Polk is widely considered the world’s best player of Heads-up No-Limit Texas Hold’em, with total live tournament earnings of more than $3.6 million. Kim, Li and Les are also among the Top 10 players in the professional Heads-up game, which is largely played online.
“My strategy will change more so than when playing against human players,” Polk added. “I think there will be less hand reading, so to speak, and less mind games. In some ways, I think it will be nice as I can focus on playing a more pure game, and not have to worry about if he thinks that I think, etc. So I am looking forward to the match.”
“Rivers Casino is proud to partner with the number-one graduate school of computer science in the U.S., Carnegie Mellon University, right here in our own backyard,” said Craig Clark, general manager of Rivers Casino. “Regardless of whether man or machine prevails, this history-making experiment is a great win for Pittsburgh.”
The competition has been designed to ensure that the outcome is scientifically significant and not a result of luck. In addition to the large number of hands, the players will be paired to play duplicate matches – Player A will receive the same cards as the computer receives against Player B, and vice versa. One of the human players will be in isolation to prevent any comparison of the cards. The same arrangement applies to Players C and D.
Play will proceed in two 750-hand sessions per day for 13 days over a two-week period, with one day set aside so the human players can rest.
Sandholm said imperfect information games such as poker are tremendously difficult because each player must reason what the opponent’s actions signal about the opponent’s cards, and what the player’s own actions signal to the opponent. A no-limit game, in which players may bet or raise any amount up to all their chips, adds even greater complexity.
Two-player, no-limit Hold’em, Sandholm said, has 10161 (1 followed by 161 zeroes) situations, or information sets, that a player may face – vastly more than all of the atoms in the universe. By contrast, the easier game of limit Hold’em, in which bets and raises are limited to a pre-determined amount, has only 1013 (1 followed by 13 zeroes) information sets.
A computer poker group at the University of Alberta, headed by CMU alumnus Michael Bowling, reported earlier this year in the journal Science that it has near-optimally solved that simpler game.
To tackle the tougher no-limit version, Claudico was built using algorithms that analyzed the basic rules of poker to devise a winning strategy, rather than try to encode the tricks and strategies of human experts. “Claudico” is Latin for “limp.” In poker, limping means to get into a hand by calling, rather than raising or folding. Humans generally dismiss limping as bad strategy, but Claudico embraces it.
“The pros may find that playing Claudico is like playing a Martian,” said Sandholm, noting limping is just one of the ways the computer differs from human players.
Even an abstracted version of the no-limit game was so large that it necessitated that Sandholm and his Ph.D. students, Sam Ganzfried and Noam Brown, use the Pittsburgh Supercomputing Center’s Blacklight supercomputer to compute Claudico’s strategy. Blacklight has a huge amount of random access memory – 16 trillion bytes, or roughly 8,000 times more than the most powerful tablet computers. Though Claudico will run on a CMU computer as it plays the pros, it will use Blacklight during the event to continuously improve its strategy.
The competition continues Carnegie Mellon’s pioneering research in artificial intelligence, which began with the creation of the first AI program, Logic Theorist, in 1956. The top-ranked School of Computer Science includes the world’s first Marching Learning Department and some of the world’s leading scientists in computational game theory, market design, natural language processing, computer vision, speech translation, thought identification and collaboration among intelligent agents.
During the 1970s and 80s, Hans Berliner, then a CMU senior research scientist, worked on a series of chess-playing machines, including Hitech, which, in 1985, was the first to achieve the rank of senior master. In the late 80s, three CMU graduate students, Feng-hsiung Hsu, Murray Campbell and Thomas Anantharaman, developed a faster chess machine, ChipTest. When IBM hired the trio, ChipTest evolved into Deep Blue, which finally beat Kasparov in 1997.
IBM’s Watson, which beat Jeopardy! champions Brad Rutter and Ken Jennings in 2011, benefited from the contributions of Eric Nyberg and his students in the School of Computer Science’s Language Technologies Institute.
The site of the competition, Pittsburgh’s Rivers Casino, opened in 2009 and has been named “Best Overall Gaming Resort in Pennsylvania” for five consecutive years by Casino Player Magazine. No one under age 21 is permitted on casino property.
ABOUT CARNEGIE MELLON UNIVERSITY
Carnegie Mellon (www.cmu.edu) is a private, internationally ranked research university with programs in areas ranging from science, technology and business, to public policy, the humanities and the arts. More than 12,000 students in the university’s seven schools and colleges benefit from a small student-to-faculty ratio and an education characterized by its focus on creating and implementing solutions for real problems, interdisciplinary collaboration, and innovation. A global university, Carnegie Mellon has campuses in Pittsburgh, Pa., California’s Silicon Valley and Qatar, and programs in Africa, Asia, Australia, Europe and Mexico.
ABOUT PITTSBURGH SUPERCOMPUTING CENTER
The Pittsburgh Supercomputing Center is a joint effort of Carnegie Mellon University and the University of Pittsburgh. PSC provides high-performance and data-intensive computing resources to the national research community. Established in 1986, PSC is supported by several federal agencies, the Commonwealth of Pennsylvania and private industry, and is a leading partner in the National Science Foundation XSEDE program.
ABOUT RIVERS CASINO
Opened in 2009, Rivers Casino has been voted a 2014 “Best Place to Work” in the Pittsburgh Business Times, "Best Overall Gaming Resort" in Pennsylvania by Casino Player magazine and "Best Overall Casino" in Pennsylvania by Strictly Slots magazine. The casino features more than 2,900 slots, 83 table games, a 30-table poker room, nine distinctive restaurants and bars, a riverside amphitheater, a multi-purpose event space, live music performances, free parking and multiple promotions and giveaways daily. Already, more than $406 million in jackpots have been awarded to players at Rivers Casino. For more information, visit riverscasino.com.
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