It's Go time



It's Go time: U of S prof shocked at computer program's victories

The two victories of a Google program against a human board game master have taken the computer science community completely off guard. “The fact we’re sitting here watching it not just playing but winning, is really shocking,” said Kevin Stanley, assistant professor of computer sciences at the University of Saskatchewan.

Lee Sedol of South Korea, one of the best Go players in the world with 18 world championships, is facing off against Google’s Alpha Go program in a best of five championship. Go is an ancient two-player game with simple rules, requiring complex strategies. Sedol was grim and ashen after Thursday’s contest, his second straight loss, which lasted more than four hours. “I’m quite speechless,” he said. “It was a clear loss on my part. From the beginning, there was no moment I thought I was leading.”

Even last fall, Stanley was telling students such a formidable computer program was a decade away. The best Go programs at the time could only play at an amateur level. In mastering other games, such as checkers or chess, computer programs were able to determine their best possible move through brute force computing power that considered all possible outcomes. But that approach didn’t work for G0 — with its huge board, the game has more possible moves than all the atoms in the universe, Stanley said. Instead of having to figure out the best move from a near infinite selection, AlphaGo considers what human players have done at a similar board state based on 30 million positions. To refine the program, programmers had it play itself millions of times.

“They’re not actually trying to solve Go, they’re trying to become a great Go player,” Stanley said. “That’s not surprising it’s come out of Google, because they’ve got a lot of money in pattern matching. They want to know if you type a search sequence, what are you really looking for.” The approach is becoming a common one to deal with vast amounts of data, Stanley said.

The three remaining games run until Tuesday. Even if Lee loses the third game, he will play all five. Lee, 33, brimmed with confidence two weeks ago, but that confidence was missing after two straight defeats. “The third game is not going to be easy for me,” he said.

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