Life In 19x19

quantumf wrote:I was struck by how much poorer Tromp played in the last few games compared to how well he played in the first one. I can only assume that he was actually based in Europe, and having to play games that started at 2am. Certainly I wouldn't be able to manage that more than once.

In the first game Zen had a big lead and squandered it with random tenukis. Tromp was starting the games in New York at 8pm each night. Before the match I'd thought that multiple games would favor a human, because they can learn the computer's weaknesses. I guess there's also fatigue to consider though. The last game in particular was on a Monday night and we can assume John has a job. He may have been tired.

Regardless, John fought hard and put on a good show. Overall Zen's performance was very impressive.

I hope we can see more of these competitions. Maybe the bots will be ready for Magicwand soon...

Yup, Zen was leading the first game from the opening. I got the feeling in later games that Tromp was trying to out-Zen Zen with a "whatever you can do to me, I can do better" attitude, e.g. h9 in game 4, and then n6 cutting back the same way Zen cut him at h8, but an awful tenuki. Or his k10 in game 2 struck me as a mistake as it seemed to pretend g14 was a pass, k13 seemed better and when Zen played k14 it seemed to agree that letting it separate was a bad choice. Then Tromp's cut at k13 seemed to be inspired by Zen's cut at h11 in game 1 which worked out well for Zen, but his k13 was poor. So he learnt from his past games and got worse . Zen is good at handling centre influence fights and making weird central moves work, unpractised humans are not.

I was also struck by Zen's ability at leaning attacks, for example in the first game dying in the lower left corner looked kinda stupid, but it seems the plan was to get kikashi to set up the kill on the group above which I'm still not convinced didn't work. You do sometimes see this kind of thing in pro games, but you have to be soooooo confident in your reading to commit such a huge local loss. Or m9 in game 2, trying to cut the escape route of the lower left group in sente was nice.

I don't think we need to make excuses for Tromp for losing, Zen is strong. I, for one, welcome our new computer overlords!

does that mean i can not give Zen 3 stone handy?

It probably does. In fact, it can probably give you 2 stones :p

Magicwand wrote:does that mean i can not give Zen 3 stone handy?

Depends on whether you want to win or lose.

illluck wrote:It probably does. In fact, it can probably give you 2 stones :p

Them's fightin' words!

gogameguru wrote:In the first game Zen had a big lead and squandered it with random tenukis. Tromp was starting the games in New York at 8pm each night. Before the match I'd thought that multiple games would favor a human, because they can learn the computer's weaknesses.

That may well be the explanation of why Tromp tried changing style. Presumably he knows about the behavior of this sort of algorithm.

a) Without anything being wrong with the algorithm the progamr can "make mistakes" (not play the best move). This is a matter of probability. Comparing the results of a large number of playouts following move A and move B, if A is the better move the percentage of victories will be higher than that of B. Usually, not always. Increasing the number of playouts will decreases the frequency of tis sort of error but that takes more time (or more crunch power for a given amount of time) and above a certain point the amount of improvement for each added playout becomes less and less (aka: diminishing returns).

b) The programs using a more straightforward AI might have weaknesses that could be learned. It appears that the programs using this sort of algortihm tend to play a "loose" style. Maybe that's a weakness compared to playing a territorially tight style but that's the sort of thing different pros would dispute.

You need to keep in mind that these programs do not always make the same move from the same position. Probability again. The closer the value of the second best move is to the best move the greater chance it would be selected.

And if one had little experience with humans who played this style preactice might be in order. But I wouldn't call that "learning a weakness".

Look at these games? If you didn't know which was the human player and which the computer would you have been able to tell? It might be interesting to conduct an experiment. We get presented with a number of game records and told that a third of them are between a human and a computer, a third beteen two humans, and a third between two programs and we see how successful we are at correctly identifying. Might start simpler with a number all known to be human vs computer but we aren't told whether the computer was playing white or black.

If you're thinking of people who have previously seen MCTS bots, the first three games would be pretty easy--they all have those characteristic floating center moves.

The first three games were posted. Why not the fourth?

I don't know where they weren't posted, but all four were on the computer go mailing list and are now on the gogameguru site.

imabuddha wrote:

Magicwand wrote:does that mean i can not give Zen 3 stone handy?

Depends on whether you want to win or lose.

i was curious how strong the program is and viewed few games.
even game i will crush him. 2 stone handy..i think i will win easily.
3 stone??? i am not sure but i think i will win.
i will play one game soon as i have some free time and let you know what happened.

how do i play this Zen program...????
i need some instruction to play this Zen

Magicwand wrote:i was curious how strong the program is and viewed few games.
even game i will crush him. 2 stone handy..i think i will win easily.
3 stone??? i am not sure but i think i will win.
i will play one game soon as i have some free time and let you know what happened.

Please do

It would be very interesting to hear, and see, how you did against it.

@Magicwand: I haven't played zen for a few months now. Before what I did was to watch its current game and try to see when the opponent/zen might resign and then switch to the games list (before the game actually ends) and quickly try to accept the open game it comes up with next (it helps if you fan Zen and use your fan games list because you can save seconds from not having to find the newly-created game). Not sure about now, but a few months back the open game disappears sometimes, so you have to be prepared to immediately find the new open game if it does that.

Don't try to manipulate default handicap - you won't have time.