Opening problems for AI: Problem 43

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Bill Spight
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Re: Opening problems for AI: Problem 43

Post by Bill Spight »

Uberdude wrote:I've seen Elf (v2 I think) have a blindspot and some % winrate change when shown the shockingly unusual move 3 of a 3-4 point instead of a 4-4. Other bots are less blinkered and more reliable for analysis IMO.
Well, the bots are at present good tools to assist a human analyst, but I would not rely upon any computer program alone for analysis. They are not trained to be analysts. Now, lightvector has used human games in training KataGo to make it better for analysis, but the main impetus for bot development is to increase its overall playing strength. The same seems to be true for chess engines, some 25 years or so since the first superhuman engines appeared. Chess engines still have well known blind spots. :)

Ordinarily I would not be surprised that KataGo or any other bot would prefer a different play than Elf. From what little information I have, a concordance rate between bots of around 80% is not unexpected. I do expect bots to agree about sufficiently bad human errors, which is the case here. KataGo figures a winrate loss for Sansa's play at 8%, about half the loss that Elf figures, but that's in line with how differently they estimate winrates. I am however surprised that, having spent at least 143.8k rollouts on this position, Elf did not pick up KataGo's top choice and give it at least 1500 rollouts.
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Re: Opening problems for AI: Problem 43

Post by ez4u »

Bill Spight wrote:
yoyoma wrote:
Click Here To Show Diagram Code
[go]$$Wcm18 katago evals:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . , . . . . . c . . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X b . . . f . , . . . . . , . . . |
$$ | . e O . O . X . . . . . . . . . . . . |
$$ | . . g . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Code: Select all

a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts
Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.
This is great! :)

Elf apparently developed a blind spot that kept it from exploring alternatives. It is extremely rare for it to like a play so much that it gives it over 100k rollouts.

How many rollouts does KataGo give these different options?
First, here is katago's policy. Elf's preferred play is high but not as high as the upper left.
Bill number 43 policy.jpg
Bill number 43 policy.jpg (131.65 KiB) Viewed 21641 times
Of course the PO's depend on how long we search. :)
But after 2.8 million... (note my komi was set to 6.5 points and therefore the winrates are quite different)
Bill number 43 analysis.jpg
Bill number 43 analysis.jpg (80.91 KiB) Viewed 21641 times
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Re: Opening problems for AI: Problem 43

Post by Bill Spight »

ez4u wrote:First, here is katago's policy. Elf's preferred play is high but not as high as the upper left.
Bill number 43 policy.jpg
Of course the PO's depend on how long we search. :)
But after 2.8 million... (note my komi was set to 6.5 points and therefore the winrates are quite different)
Bill number 43 analysis.jpg
This is great, Dave! Many thanks. :salute: :salute: :salute:

Two comments. First, with only 521 playouts, KataGo's evaluation of Sansa's 5-4 move in the top right has a large margin of error. Elf does better in this regard, by inheriting the evaluation from its best reply to that move. I expect that yoyoma does even better, by making the play itself to get its evaluation with several thousand rollouts.

Second, even though I have no experience with KataGo, I think that the 3% winrate difference between KataGo's choice and Elf's, with 1.6M and 147K rollouts, respectively, puts Elf's choice in the doubtful category.

The fact that Elf concentrates on one play to the virtual exclusion of others indicates that it likes that play. However, that does not mean that other bots will like it much. Therefore, this will be the last "only move" problem.
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Re: Opening problems for AI: Problem 43

Post by Gomoto »

Therefore, this will be the last "only move" problem.

The only move now ;-)
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Re: Opening problems for AI: Problem 43

Post by dhu163 »

Speculatively:
Current position:
1. D4 is very standard. B3 is met by tenuki because D4 is already only threatening 13 points, half a move, and B has aji of E2 and F5. Later, B can still play D4 and D3 potentially in sente. The biggest difference is probably when B threatens the E5 cut, say if B has D8 later (though small). Even if B B3 is sente on W C2 later, the local side territory is similar +4 in centre, -4 on side if B G3 was dead. However, B3 has a clear loss in the centre. Sometimes B3 is correct, but that is mainly when B already say has a move at F2, or W does. Getting thick has its own extra value of connecting groups so that the groups is more moves away from death and may either tenuki more or play stronger counterattacks.

Opp to play
1. D4

Past:
1. This is usually premature for W to play like this and although G3 is misplaced, W is taking gote and B3 isn't sente.

Check:
1.
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