Author: Omid David Tabibi
Date: 14:49:45 08/21/03
Go up one level in this thread
On August 21, 2003 at 17:34:35, Sune Fischer wrote:
>On August 21, 2003 at 17:25:46, Omid David Tabibi wrote:
>
>
>>>I think the competition is rather fierce at the top, so their decision is
>>>understandable if the choice is between gaining X Elo in real games, or solving
>>>artificial test positions.
>>
>>True, but the position in question was no artificial. It could very well arise
>>in actual games, and it can certainly arise many times in the huge search trees,
>>with one such horrible error wreaking havoc to the whole search tree.
>>
>>The probability of such an occurrence is very low, but if it occurs it's a total
>>disaster!
>
>The problem for us observers is that we only discover whenever it fails, we
>never realize that those 10 other games turned into a win because of the
>pruning.
>
>We thus falsely conclude it is hurting the program.
>
>>Imagine Junior playing aginst Kasparov in the 6th match, and this position
>>arises. Junior would draw the won match!
>
>Yes, but imagine the odds of that happening!
>
>I remember another famous computer that didn't use nullmove when playing Garry
>some years ago, probably rooted in the same fear.
>
>>As a real life example, take the frist game of Fritz vs Kramnik in Bahrain. Had
>>Fritz had blockage detection knowledge, it wouldn't have played Bg5 and could
>>have very well gone on to win...
>
>Right they can always get smarter, and just imagine how much they could prune if
>they understood blockages! :)
No need to imagine, just take a look:
Deep Fritz vs Kramnik, position after 26.Bg5
[D]3k4/2p1b3/1p2p1p1/p1p1P1B1/P1P3pP/1P6/5P2/6K1 b - - 0 26
Analysis by Genesis on my 733 Mhz system:
depth time nodes score variation
1/ 3-> 0.00 0k -1.05 1...e7g5 2.h4g5
2/ 5-> 0.01 0k -1.21 1...c7c6 2.g5e7 d8e7
3/ 6-> 0.01 0k -1.17 1...c7c6 2.g5e7 d8e7 3.g1g2
4/ 7-> 0.01 0k -1.01 1...d8e8 2.g1g2 e8f8 3.g5h6 f8e8
5/10-> 0.01 1k -1.17 1...d8e8 2.g1g2 c7c6 3.g5e7 e8e7
6/10 0.02 3k -- 1...d8d7
6/10 0.03 5k -0.89 1...d8d7 2.g1g2 e7f8 3.g2g3 f8g7
4.g3f4
6/10-> 0.03 5k -0.89 1...d8d7 2.g1g2 e7f8 3.g2g3 f8g7
4.g3f4
7/11 0.04 8k -- 1...d8d7
7/13 0.05 10k -0.02 1...d8d7 2.g1g2 e7f8 3.g2g3 f8g7
4.g5f4 b6b5
7/13-> 0.06 11k -0.02 1...d8d7 2.g1g2 e7f8 3.g2g3 f8g7
4.g5f4 b6b5
8/13 0.08 18k 0.13 1...d8d7 2.g5e7 d7e7 3.g1g2 e7d7
4.g2g3 c7c6 5.g3g4
8/13 0.08 19k 0.00 1...e7g5 2.h4g5
8/13-> 0.10 24k 0.00 1...e7g5 2.h4g5
9/13 0.10 26k 0.00 1...e7g5 2.h4g5
9/13-> 0.14 37k 0.00 1...e7g5 2.h4g5
10/13 0.15 40k 0.00 1...e7g5 2.h4g5
10/15-> 0.23 65k 0.00 1...e7g5 2.h4g5
11/15 0.25 70k 0.00 1...e7g5 2.h4g5
11/16-> 0.38 114k 0.00 1...e7g5 2.h4g5
12/16 0.40 122k 0.00 1...e7g5 2.h4g5
12/18-> 0.57 178k 0.00 1...e7g5 2.h4g5
13/18 0.59 189k 0.00 1...e7g5 2.h4g5
13/19-> 0.80 266k 0.00 1...e7g5 2.h4g5
14/19 0.84 281k 0.00 1...e7g5 2.h4g5
14/20-> 1.21 415k 0.00 1...e7g5 2.h4g5
15/20 1.26 436k 0.00 1...e7g5 2.h4g5
15/21-> 1.91 685k 0.00 1...e7g5 2.h4g5
16/21 1.97 710k 0.00 1...e7g5 2.h4g5
16/22-> 3.10 1149k 0.00 1...e7g5 2.h4g5
17/22 3.20 1186k 0.00 1...e7g5 2.h4g5
17/24-> 5.14 1945k 0.00 1...e7g5 2.h4g5
18/24 5.25 1989k 0.00 1...e7g5 2.h4g5
18/26-> 8.53 3313k 0.00 1...e7g5 2.h4g5
19/26 8.83 3440k 0.00 1...e7g5 2.h4g5
19/26-> 15.64 6192k 0.00 1...e7g5 2.h4g5
[D]8/1k4pp/pP1pb3/P1p2pP1/2B2P2/3P3P/1K1P4/8 b - - 0 1
depth time nodes score variation
1/ 4-> 0.02 0k 1.65 1...e6d7
2/ 6-> 0.02 0k 1.61 1...d6d5 2.c4b3
3/ 8-> 0.02 0k 0.00 1...e6c4 2.d3c4 g7g6
4/ 8-> 0.02 0k 0.00 1...e6c4 2.d3c4 g7g6
5/ 8-> 0.03 1k 0.00 1...e6c4 2.d3c4 g7g6
6/ 9 0.03 1k 0.00 1...e6c4 2.d3c4 g7g6
6/ 9-> 0.03 2k 0.00 1...e6c4 2.d3c4 g7g6
7/10 0.04 3k 0.00 1...e6c4 2.d3c4 g7g6
7/10-> 0.04 4k 0.00 1...e6c4 2.d3c4 g7g6
8/13 0.05 7k 0.00 1...e6c4 2.d3c4 g7g6
8/13-> 0.06 9k 0.00 1...e6c4 2.d3c4 g7g6
9/15 0.08 14k 0.00 1...e6c4 2.d3c4 g7g6
9/15-> 0.11 21k 0.00 1...e6c4 2.d3c4 g7g6
10/15 0.14 30k 0.00 1...e6c4 2.d3c4 g7g6
10/15-> 0.19 45k 0.00 1...e6c4 2.d3c4 g7g6
11/17 0.23 60k 0.00 1...e6c4 2.d3c4 g7g6
11/17-> 0.35 98k 0.00 1...e6c4 2.d3c4 g7g6
12/18 0.42 123k 0.00 1...e6c4 2.d3c4 g7g6
12/18-> 0.66 200k 0.00 1...e6c4 2.d3c4 g7g6
13/19 0.82 248k 0.00 1...e6c4 2.d3c4 g7g6
13/19-> 1.34 423k 0.00 1...e6c4 2.d3c4 g7g6
14/22 1.62 517k 0.00 1...e6c4 2.d3c4 g7g6
14/22-> 2.66 857k 0.00 1...e6c4 2.d3c4 g7g6
15/23 3.03 985k 0.00 1...e6c4 2.d3c4 g7g6
15/23-> 5.23 1735k 0.00 1...e6c4 2.d3c4 g7g6
The only correct move is 1...Bxc4 which Genesis finds at ply 3 in 0.02 seconds.
All other moves lose.
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