Author: Robert Hyatt
Date: 08:46:41 06/05/00
Go up one level in this thread
On June 05, 2000 at 10:31:32, blass uri wrote:
>On June 05, 2000 at 09:09:51, Robert Hyatt wrote:
>
>>On June 05, 2000 at 08:22:44, Steffen Jakob wrote:
>>
>>>Hi!
>>>
>>>This is a position from an interesting standard game MissSilicon - Hossa, played
>>>today at ICC:
>>>
>>>[D]5k2/7K/6P1/1p3p2/1P5P/1Pb5/8/8 w
>>
>>
>>
>>I think there are times where you have to depend on your search. Normally
>>this is won by black, because black has a bishop to stop white's pawns. I
>>suspect that if you try to write special-purpose code to catch this, it will
>>end up being wrong more than it is right.
>
>I agree that writing a special code to catch this case and many other cases is
>not trivial but I believe that it is not impossible.
>
> This is a precise tempo-counting
>>issue that just barely lets the 'loser' win.
>>
>>I'd likely just take the loss and run. It takes Crafty 9 plies (0 seconds
>>of course) to see that the bishop is not winning. I don't see an obvious
>>evaluation trick to make this show up faster...
>
>Hiarcs7.32 needs only 5 plies to see that white is winning because of
>extensions.
>
>Uri
That doesn't matter. How _long_ does Hiarcs need? It doesn't matter whether
you need 5 plies or 9 plies. What matters is "how many seconds"??? Because it
is easy to extend a lot and pick this up quicker (shallower plies) but take
longer overall to find the problem. Here is what I get, for reference:
nss depth time score variation (1)
starting thread 1
starting thread 2
starting thread 3
1 0.00 -5.90 1. h5
1-> 0.00 -5.90 1. h56
2 0.00 -- 1. h5
2 0.00 -6.77 1. h5 Bxb4
2 0.00 -6.52 1. Kh6 f4
2-> 0.01 -6.52 1. Kh6 f4
3 0.01 -6.22 1. Kh6 f4 2. h5
3 0.01 ++ 1. h5!!
3 0.01 -5.40 1. h5 Bg7 2. h6
3-> 0.01 -5.40 1. h5 Bg7 2. h6
4 0.02 -5.14 1. h5 f4 2. h6 Bxb4
4-> 0.02 -5.14 1. h5 f4 2. h6 Bxb4
5 0.23 ++ 1. h5!!
5 0.24 -3.95 1. h5 f4 2. h6 f3 3. g7+ Bxg7 4. hxg7+
5-> 0.24 -3.95 1. h5 f4 2. h6 f3 3. g7+ Bxg7 4. hxg7+
6 0.25 -4.26 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4
6-> 0.26 -4.26 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4
7 0.27 -4.26 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
Kh7
7-> 0.27 -4.26 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
Kh7
8 0.28 -4.43 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
g7+ Kg8 5. Kg5
8-> 0.29 -4.43 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
g7+ Kg8 5. Kg5
9 0.38 ++ 1. h5!!
9 0.49 3.78 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 Kg7 5. Kxf5
9-> 0.49 3.78 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 Kg7 5. Kxf5
10 0.50 3.68 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kg7
10-> 0.51 3.68 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kg7
11 0.52 3.78 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kg7 6. Kf5
11-> 0.53 3.78 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kg7 6. Kf5
12 0.55 3.88 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7
(2) 12-> 0.58 3.88 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7
13 0.60 3.78 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7 7. Kf5
(2) 13-> 0.63 3.78 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7 7. Kf5
14 0.66 ++ 1. h5!!
14 6.49 4.19 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kf8 6. Kg5 Ke7 7. g7
Kf7 8. Kh6
14-> 6.56 4.19 1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
Kg5 f4 5. Kxf4 Kf8 6. Kg5 Ke7 7. g7
Kf7 8. Kh6
Crafty finds the right move from depth=1. After .38 seconds it realizes that
white is winning. I can crank up the passed pawn extension and see this
quicker in terms of depth, but the time will probably be slower overall. IE
don't be mislead by 'shallow depth finding'. I think depth doesn't matter at
all. It is _time_.
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