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Computer Cracks 5x5 Go
gustgr writes "The American Go Association is reporting that Go for the 5x5 board has been solved by the computer program MIGOS, reports the program's creator, Erik Van Der Werk, a professor at the University of Maastricht in Holland. At about a quarter of the full-board version, 5x5 go is miniscule, similar in scale to "solving" 2X2 chess. The fact that a programmer would even consider this a noteworthy challenge is itself a remarkable testament to the game's complexity. Van Der Werk's approach is described in detail in an
article at the Netherlands Organization for Scientific Research (NOSR)."
5x5 is 1/4 the size of 19x19??? More like 1/14th.
The way that chess games work is they check n ammount of moves into the future. With each iteration into the next move it splits off into a massive tree of moves. As an example, the first iteration has 10 potential moves, the next has 100 and the next has 1,000 With Go as an example there may be 100 potential moves on the first iteration and then 10,000 and then 10,000,000 The number of potential moves grows way faster then in chess.
For another thing, go is spectacularly more complex than chess. The very best go programs are competition only for weak amateurs. There's an archived NYT article that summarizes the problems reasonably well.
Although the standard go board is 19x19 intersections, the game scales, unlike chess. Things you learn on a small board are sometimes applicable to larger ones. A 5x5 is usually not interesting for human play; most consider 9x9 the minimum size for a worthwhile game. This means that a computer has been programmed to force a guaranteed win at a smaller size, and hopefully paves the way for further development and understanding.
This isn't as much "normalization" as it is "don't take so many drugs when you're designing tables."
A full-size Go board is 19x19, but you're right in your main point.
I found the meaning of life the other day, but I had write-only access.
AFAIK, the current state of the art of Go on computers is Goemate and Go4++.
GNU Go is actively developed, but it still does not match commercial Go software, ranking 1-2 stones weaker. It is rated from 8 to 9 kru, which is a weak amateur.
Computers have thus far not been too great at cracking go via the usual searching algorithms, as it has a high branching factor - starting at 361, much higher than chess! It is only recently that Go programs have even begun to achieve low levels of competence. Besides the limited searching and pattern recognition of current software, future programs may improve by decomposing Go into 'subgames', allowing it to be more readily attacked.
A 5x5 go board has only 847,288,609,443 possible game states, even including impossible boards. Assuming the relatively tame pace of scoring 100,000 boards per second towards completion, which on a board of that size is trivial, this solution takes a simple brute-force time of 98 days. That solution space can be cut down by almost two orders of magnitude with simple reflection and rotation tricks, implying a realtime tree search space of about a day and a half.
Given that my full board scorer moves faster than that, and given that the university probably has more than one PC to work with, I wonder how it is that anyone can justify this as something larger than a publicity stunt, especially given that none of go's emergent structures even fit onto a 5x5 board.
This is horseshit, in short. Mod story down.
StoneCypher is Full of BS
His name is Eric van der Werf.
a professor at the University of Maastricht
He is not a professor. He was a Ph.D. student. He received his Ph.D. title January 27 of this year.
in Holland.
That should be "The Netherlands". Holland is part of The Netherlands, but Maastricht is not located in Holland.
At about a quarter of the full-board version, 5x5 go
That's about 1/14th of a full board (25 points as opposed to 361 points).
is miniscule, similar in scale to "solving" 2X2 chess.
It is similar to solving 5x5 or 6x6 chess.
The fact that a programmer
Calling Van der Werf a "professor" is a bit too much, but calling him a "programmer" is not enough.
would even consider this a noteworthy challenge is itself a remarkable testament to the game's complexity.
Basically, it was not done before, and could be done with a couple of weeks computation time. That's not to belittle Eric's work; it is only a small part of his work. Read his thesis to see what he has done for the field of Go research.
Van Der Werk's
Again, it is "Van der Werf".
approach is described in detail in an article at the Netherlands Organization for Scientific Research (NOSR).
That should be NWO, not NOSR, and the approach is not described in detail in the article. For details, visit Eric's website.