Author: John Merlino
Date: 09:20:05 01/24/05
Go up one level in this thread
On January 24, 2005 at 11:21:14, Wilhelm Hudetz wrote:
>On January 24, 2005 at 09:54:04, Wilhelm Hudetz wrote:
>
>>Hi Jason,
>>
>>I think your right.
>>I read a german translation of the manual from CM4000-Turbo,
>>and there stands, if you set minus CM will more look to find a winning
>>way in drawing positions.
>>I think there is a false translation!
>>Ok, I check this, more later.
>>Thank you
>>
>>Wilhelm
>>I better should read the english manual....
>
>I make some tests with different positions
>and cfd has big influence of the search.
>So I think it can not only be a parameter for accept draw!?
>
>here a testposition as example:
>
>8/5BK1/8/2kn4/1p2b3/8/1R3P2/8 w - - 0 62
>
>try different values for cfd and look how long it take to find Rd2.
>
>In many games I have controlled I coudn´t see that CM accept a
>draw when he is in plus (C3PO has cfd=-10).
>So I don´t know whats realy right.
>
>regards
>Wilhelm
Indeed, the Contempt for Draw value affects the search VERY MUCH! Johan could
probably give a more complete description of how this works, but, in a nutshell:
A low (negative) contempt for draw means that the engine will look for and
attempt to steer the game towards drawish lines, even at the cost of improving
its position. It will consistently attempt to get draws by repetition and will
very likely trade material to simplify. This can result in boring play, and is
likely to reduce the quality of play.
A high (positive) contempt for draw means that the engine will attempt to avoid
drawish positions, even at the cost of losing half a point. You can easily see
an example of how this can reduce the quality of play by looking at the first
game in the CM vs. Christiansen match in which the Alekhine personality was
used. This personality has a +3 cfd value, which means that it won't accept a
draw unless it is down by at least 3 points!
The engine made some very poor moves attempting to attack and avoiding
simplification.
[Date "2002.9.28"]
[Round ""]
[White "CM9000 Alekhine"]
[Black "LarryC"]
[TimeControl "120+120"]
[Result "0-1"]
1.e4 {00:00 (Book)} 1...c6 {00:18} 2.d4 {00:00 (Book)} 2...d5 {00:30}
3.exd5 {00:00 {Book)} 3...cxd5 {00:44} 4.c4 {00:00 (Book)} 4...Nf6 {
00:59} 5.Nc3 {00:00 (Book)} 5...e6 {01:15} 6.Nf3 {00:00 (Book)} 6...Be7
{01:37} 7.cxd5 {00:00 (Book)} 7...Nxd5 {01:52} 8.Bb5+ {00:00 (Book)}
8...Nc6 {05:37} 9.Ne5 {02:08 (Score: 0.86, Depth: 3/12}} 9...Bd7 {07:11}
10.Bxc6 {02:52 (Score: 0.87, Depth: 3/12)} 10...Bxc6 {07:31} 11.Nxc6 {
05:03 {Score: 0.53, Depth: 3/12)} 11...bxc6 {07:59} 12.Nxd5 {06:50
(Score: 0.24, Depth: 4/13)} 12...cxd5 {09:13} 13.O-O {07:53 (Score:
-0.01, Depth: 4/13)} 13...O-O {09:26} 14.Bf4 {10:05 (Score: 0.05, Depth:
4/13)} 14...Qb6 {12:09} 15.Qd2 {10:08 (Score: 0.05, Depth: 4/13)}
15...Bf6 {13:02} 16.Be3 {11:31 (Score: 0.09, Depth: 4/13)} 16...a5 {
13:34} 17.Rac1 {13:52 (Score: 0.28, Depth: 4/13)} 17...Qb4 {15:09}
18.Rfd1 {15:29 (Score: 0.39, Depth: 3/12)} 18...Rfb8 {16:38} 19.Rc3 {
17:44 (Score: 0.51, Depth: 3/12)} 19...Qa4 {21:19} 20.Rdc1 {19:18
(Score: 0.67, Depth: 3/12)} 20...h6 {22:59} 21.b3 {21:33 (Score: 0.62,
Depth: 3/12)} 21...Qb4 {23:29} 22.R1c2 {22:45 (Score: 0.58, Depth: 2/11}
} 22...Re8 {25:16} 23.h3 {25:03 (Score: 0.54, Depth: 3/12)} 23...a4 {
26:06} 24.Rc8 {27:20 (Score: 0.34, Depth: 4/13)} 24...Qxd2 {26:41}
25.Rxe8+ {27:35 (Score: 0.28, Depth: 6/14)} 25...Rxe8 {26:58} 26.Rxd2 {
31:15 (Score: 0.02, Depth: 8/15)} 26...axb3 {29:21} 27.axb3 {31:15
(Score: -0.22, Depth: 7/13)} 27...Rb8 {29:53} 28.Rb2 {32:24 (Score:
-0.15, Depth: 8/14)} 28...Rb4 {35:32} 29.Kf1 {34:06 (Score: -0.10,
Depth: 8/14)} 29...Kf8 {36:33} 30.Ke2 {34:43 (Score: -0.10, Depth: 8/14}
} 30...Bxd4 {37:22} 31.Bxd4 {37:02 (Score: -0.66, Depth: 9/15)}
31...Rxd4 {37:36} 32.b4 {38:06 (Score: -0.77, Depth: 9/14)} 32...Ke7 {
42:59} 33.b5 {38:06 (Score: -0.99, Depth: 10/15)} 33...Rc4 {53:20} 34.b6
{40:07 (Score: -1.09, Depth: 8/13)} 34...Rc8 {53:35} 35.h4 {43:29
(Score: -1.47, Depth: 9/14)} 35...Kd6 {56:02} 36.Rb3 {43:30 (Score:
-1.43, Depth: 9/14)} 36...Rb8 {57:10} 37.Rg3 {43:55 (Score: -1.39,
Depth: 9/14)} 37...g6 {59:43} 38.h5 {43:57 (Score: -1.44, Depth: 9/14)}
38...g5 {01:00:30} 39.Ra3 {44:41 (Score: -1.47, Depth: 9/14)} 39...Rxb6
{01:01:23} 40.Ra7 {47:11 (Score: -1.38, Depth: 10/14)} 40...Rb2+ {
01:02:01} 41.Kf1 {48:46 (Score: -1.35, Depth: 10/14)} 41...f5 {01:06:48}
42.Rh7 {50:10 (Score: -1.17, Depth: 10/14)} 42...d4 {01:15:06} 43.Rxh6 {
50:10 (Score: -1.31, Depth: 11/15)} 43...d3 {01:15:56} 44.Ke1 {50:59
(Score: -1.43, Depth: 10/14)} 44...Ke5 {01:22:58} 45.Rh8 {52:47 (Score:
-1.34, Depth: 10/14)} 45...Rb1+ {01:24:23} 46.Kd2 {52:47 (Score: -0.73,
Depth: 1/2)} 46...Rf1 {01:24:38} 47.f3 {54:40 (Score: -1.60, Depth:
11/15)} 47...Rf2+ {01:24:56} 48.Kxd3 {56:13 (Score: -2.01, Depth: 11/15}
} 48...Rxg2 {01:25:17} 49.h6 {01:00:12 (Score: -2.13, Depth: 12/16)}
49...Rh2 {01:26:41} 50.Ke3 {01:01:33 (Score: -2.25, Depth: 12/16)}
50...f4+ {01:27:31} 51.Kd3 {01:01:33 (Score: -0.78, Depth: 1/2)}
51...Rf2 {01:27:49} 52.Rg8 {01:04:25 (Score: -2.40, Depth: 12/16)}
52...Rxf3+ {01:28:02} 53.Kc4 {01:05:44 (Score: -2.45, Depth: 11/15)}
53...Rh3 {01:28:16} 54.Rxg5+ {01:08:19 (Score: -2.67, Depth: 11/15)}
54...Ke4 {01:28:35} 55.Rg1 {01:11:03 (Score: -2.93, Depth: 11/15)}
55...Rxh6 {01:28:53 -- White Resigns} 0-1
Johan, as far as I know, ALWAYS uses a cfd value of 0 in tournaments with The
King.
jm
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