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Subject: Re: Test position - Dragon

Author: Will Singleton

Date: 10:01:34 06/05/04

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On June 05, 2004 at 12:53:53, Uri Blass wrote:

>On June 05, 2004 at 12:32:47, Will Singleton wrote:
>
>>On June 05, 2004 at 10:13:35, Anthony Cozzie wrote:
>>
>>>On June 04, 2004 at 19:03:53, Anthony Cozzie wrote:
>>>
>>>>From Yace-Zappa
>>>>
>>>>[D]3q1rk1/pp1bppbp/3p1npB/8/2rNP1P1/2N2P2/PPPQ4/2KR3R b - - 0 16
>>>>
>>>>1... Nf6xe4 2. f3xe4 Bg7xd4 3. Qd2-d3 b7-b5 4. Nc3-d5 Bd4-e5 5. Bh6xf8 Qd8xf8 6.
>>>>g4-g5 Qf8-g7 7. c2-c3 Rc4-a4 8. Kc1-b1 Kg8-f8
>>>> = (0.32)       Depth: 15/38    00:06:02.03     263847kN
>>>>
>>>>The game continued Nxe4 Qe3 Rxc3 bxc3 Qh6 Nf6 and now your program should be
>>>>able to see g5! and white is able to win the queen.
>>>>
>>>>Anyone out there that can avoid Nxe4 in reasonable time?
>>>>
>>>>anthony
>>>
>>>OK, as has been pointed out by about 25 people, the mistake is not Nxe4, but
>>>Bxh6 (a move which somehow I conviently omitted from the my line).
>>>
>>>[D]3q1rk1/pp1bppbp/3p2pB/8/3Nn1P1/2P1QP2/P1P5/2KR3R b - - 0 18
>>>
>>>Even this one is pretty hard for Zappa, it needs 70 seconds to realize Bxh6 is
>>>losing and 6 minutes switch to Nf6.
>>>
>>>1... Bg7xh6 2. Rh1xh6 Ne4-f6 3. Rd1-h1 e7-e5 4. Nd4-f5 Bd7xf5 5. g4xf5 Qd8-a5 6.
>>>Qe3-g5 Qa5-a3 7. Kc1-d1 Kg8-g7 8. f5xg6 f7xg6
>>> = (0.50)	Depth: 14/31	00:00:46.41	37517kN
>>>1 ...Bg7xh6--
>>> - (0.25)	Depth: 15/30	00:01:08.74	55010kN
>>>1... Bg7xh6 2. Qe3xh6 Ne4-f6 3. g4-g5 Nf6-h5 4. Rh1xh5 g6xh5 5. Rd1-h1 Qd8-a5 6.
>>>Rh1xh5 Bd7-f5 7. Nd4xf5 Qa5xf5 8. g5-g6 Qf5xg6 9. Rh5-g5 Rf8-c8 10. Rg5xg6 h7xg6
>>> = (-2.83)	Depth: 15/34	00:03:02.47	147329kN
>>>1... Ne4-f6 2. Bh6xg7 Kg8xg7 3. Nd4-f5 Bd7xf5 4. g4xf5 Qd8-a5 5. Qe3xe7 Qa5xa2
>>>6. Qe7xb7 Qa2-a3 7. Qb7-b2 Qa3-c5 8. f5xg6 f7xg6 9. Rh1-e1 Rf8-c8 10. Re1-e7
>>>Kg7-h6
>>> = (0.18)	Depth: 15/36	00:05:34.28	269390kN
>>>
>>>anthony
>>
>>
>>The time it takes to find Nf6 after seeing the problem with Bxh6 is rather long
>>for some programs.  For example, Crafty (3 min), Ruffian (1:30) and Zappa
>>(2:30).  This is because the problem occurs at a high search depth.
>>
>>Amateur does better in switching to the right move, taking only 10 sec.  It does
>>this by "cheating," which is to say, reducing the search depth when a large
>>score drop occurs.  I don't really see a downside to this.
>>
>>Crafty
>>14    191   11683 124623699  1. ... Bxh6 2. Qxh6 Nf6
>>14     16   30945 341466474  1. ... Nf6 2. Bxg7 Kxg7
>>
>>Ruffian
>>14 -161 10004 121228508  Bxh6 Qxh6 Nf6
>>14 -5   18402 223090636  Nf6 Bxg7 Kxg7
>>
>>Amateur
>>16 -243 12517 49364251 Bxh6 Qxh6 Nf6
>>13 -243 12517 49364252 Bxh6
>>13 87   13581 53146356 Nf6 Bxg7 Kxg7
>
>
>all these programs do better than movei that cannot get so deep.
>Movei find at depth 14 that Bxh6 is bad but it takes it clearly more time and
>even more nodes(movei is relatively slow searcher).
>
>Note that movei has no threat mate extensions and I suspect that threat mate
>extensions can help to find that Bxh6 is bad at least one ply earlier.
>
>Uri

OK, but do you have a comment regarding the point of my post?




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