Author: Andrew Williams
Date: 11:45:52 06/18/00
Go up one level in this thread
On June 18, 2000 at 07:14:20, Gian-Carlo Pascutto wrote:
>
>Hi all
>
>At the bottom of this post is a test position. The idea is not to check which
>programs find the correct move (should be easy), but when the program first
>spots it, with which score, when it fails high, how long it takes for the
>fail-high to resolve and what score it gets back.
>
>The idea is to see how well the programs handle this kind of positions where
>the extensions suddenly can get wild, just when the alpha-beta window opens.
>Some can handle this very well, other have the search totally blow up...
>
>I've done a bit of testing already, and the results vary rather widely...so
>I'd like to get as much data as possible on this one. If you are a programmer
>yourself, _please_ indicate what extensions your program uses, or other
>relevant info about your search. I'd like to get an idea of the do's/dont's
>when extending.
>
>Also, if anyone has other positions like this (preferrably even harder/worse),
>please share them.
>
>[D] rr4k1/pp2pp1p/q2p2p1/2pP3n/2P5/2BQP2R/PP3P2/2K4R w - - 0 19
>
>PS. Is this a forced mate? If so, how many moves exactly?
>
>--
>GCP
Hi,
This is PostModernist's output. PostModernist is an MTD(f) program. Extensions
are: one ply for check. One extra ply for checks where there's just one move
that escapes (after a number of repetetive checks, the latter goes down to 1/4
ply). I have one ply for null-move mate threats. One ply for Pawn->7th. And
one ply for certain recaptures (same square, same material value). Maximum of
one ply extension EXCEPT for the single-response to check. As you can see, PM
doesn't find the mate.
1= -185 0 171 1. a3
2= -185 0 243 1. a3
3= -197 0 658 1. Qe4 b5
4= -157 0 2742 1. Rg1 Nf6 2. Bxf6 exf6
5= -122 0 6805 1. Rxh5 gxh5 2. Rxh5 h6 3. Rxh6 Qxa2
6= -122 0 13798 1. Rxh5 gxh5 2. Rxh5 h6 3. Rxh6 Qxa2
7= -118 1 33984 1. Rxh5 gxh5 2. Rxh5 Kf8 3. a3 Ke8 4. Rxh7
8= -88 2 101781 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Qxh7 Ke8 4. Qh8
9= -40 6 273251 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Rh8 Kd7 5.
Qf5 Kc7
10= 39 8 327105 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Qxa2 5.
Qxf7
11= 94 90 3856219 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Qxa2 5.
Qxf7
12= 173 97 4151457 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Kd8 5.
Qxf7 Qxc4 6. Qxe7
13= 252 115 4946842 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Kd8 5.
Qxf7 Qxc4 6. Qxe7
14= 331 165 6978402 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Kd8 5.
Qxf7 Qxc4 6. Qxe7
15= 410 1000 40820268 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Kd8 5.
Qxf7 Qxc4 6. Qxe7
16= 489 8333 334454139 1. Rxh5 gxh5 2. Rxh5 Kf8 3. Rxh7 Ke8 4. Qf5 Kd8 5.
Qxf7 Qxc4 6. Qxe7
I think this may be another example of a position where extensions go mad:
[D] r1b2rk1/pp1n1p1p/2n1p1p1/3pPP2/3P2N1/q1PB4/3Q3R/5RK1 b - - 0 23
My program reached this position (as black) against a very skilled anti-computer
player. It's probably lost anyway, but playing exf5?? doesn't help much. My
program gets badly bogged-down with extensions here. I've not had much time to
investigate it, because I've been busy. Here's the game (not one I'm very proud
of, but whizpopper is *very* tricky):
[Event "ICS rated blitz match"]
[Site "204.178.125.65"]
[Date "2000.06.16"]
[Round "-"]
[White "whizpopper"]
[Black "PostModernist"]
[Result "1-0"]
[WhiteElo "2203"]
[BlackElo "2734"]
[TimeControl "300"]
1. e4 e6 2. Nf3 d5 3. e5 c5 4. b4 cxb4 5. a3 bxa3 6. d4 Nc6 7. c3 Nge7 8.
Bd3 Ng6 9. h4 a2 10. Rxa2 Be7 11. h5 Nf8 12. h6 g6 13. O-O Nd7 14. Nh2 O-O
15. Ba3 Bxa3 16. Nxa3 Qg5 17. f4 Qxh6 18. Ng4 Qh4 19. g3 Qxg3+ 20. Rg2 Qh4
21. Rh2 Qe7 22. f5 Qxa3 23. Qd2 exf5 24. Qh6 Re8 25. Nf6+ Nxf6 26. exf6 Nb4
27. Qg7#
{PostModernist checkmated} 1-0
Hope some of this is interesting/helpful
Andrew
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