Author: Richard Pijl
Date: 00:27:45 03/07/06
Go up one level in this thread
On March 06, 2006 at 22:49:11, Dann Corbit wrote:
>Unstoppable passed pawn. What does your program see as far as pawn score here?
>[D] 8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - bm Rxb2
You'll need to know that two connected passers beat a rook when progressed to
3rd rank (or one to 4 and 2) and the defending king is too far away.
You will not find it in reasonable time without this 'knowledge' in your passed
pawn evaluation if you are doing any kind of pruning (including nullmove
pruning)
It took me a little while to get this correct in the Baron, but now it solves it
at a 3 ply search in 0.02 seconds on a Xeon 2.8 Ghz:
ply time nodes score pv
2( 2)& 0:00.02 115 +0.78 Kf6-e6 e3-e4
2( 2)& 0:00.02 174 +0.90 Rb3-b5 Rd2-g2
2( 2)& 0:00.02 223 +0.93 Rb3-b6 e3-e4 (f5xe4)
2( 2)& 0:00.02 272 +1.01 Rb3-b7 e3-e4 (f5xe4)
2( 2)& 0:00.02 321 +1.04 Rb3-b8 e3-e4 (f5xe4)
2( 2). 0:00.02 393 +1.04 Rb3-b8 e3-e4 (f5xe4)
3( 6)& 0:00.02 557 +1.20 Rb3-b8 e3-e4 f5xe4 Kf3xe4 Rb8-d8
3( 6)+ 0:00.02 898 +1.99 Rb3xb2 (Rd2xb2) (c4-c3)
3( 6)& 0:00.02 967 +3.16 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
3( 6). 0:00.02 989 +3.16 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
4( 7)- 0:00.02 3267 +2.81 Rb3xb2 (Rd2xb2) (c4-c3) (Rb2-b6) (Kf6-e7)
(Rb6-b7)
4(13)& 0:00.03 4008 +2.81 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-c6
4(13). 0:00.03 4023 +2.81 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-c6
5(10)& 0:00.03 6517 +2.55 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-b7 Kf7-g6 Rb7-c7
5(10). 0:00.05 9175 +2.55 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-b7 Kf7-g6 Rb7-c7
6(11)& 0:00.06 16587 +2.55 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-b7 Kf7-g6 Rb7-c7 c3-c2
6(11). 0:00.08 20789 +2.55 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-b7 Kf7-g6 Rb7-c7 c3-c2
7(18)& 0:00.16 46866 +2.38 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-b7 Kf7-e6 Rb7-b6 Ke6-d7 Rb6-b7 Kd7-d6
Rb7xh7 (c3-c2) (Rh7-h6) (Kd6-d5)
7(18). 0:00.20 58808 +2.38 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-f7
Rb6-b7 Kf7-e6 Rb7-b6 Ke6-d7 Rb6-b7 Kd7-d6
Rb7xh7 (c3-c2) (Rh7-h6) (Kd6-d5)
8(16)+ 0:00.31 100415 +2.73 Rb3xb2 (Rd2xb2) (c4-c3) (Rb2-b6) (Kf6-f7)
(Rb6-b7) (Kf7-e6) (Rb7-b6) (Ke6-d7)
(Rb6-b7) (Kd7-d6)
(Rb7xh7) (c3-c2) (Rh7-h6) (Kd6-d5)
8(21)& 0:00.45 151168 +2.55 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d8 Rb7-b8 Kd8-d7 Rb8-b7 Kd7-e6
Rb7-b6 Ke6-f7 Rb6-b7 (Kf7-e6) <rep>
8(21). 0:00.56 189645 +2.55 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d8 Rb7-b8 Kd8-d7 Rb8-b7 Kd7-e6
Rb7-b6 Ke6-f7 Rb6-b7 (Kf7-e6) <rep>
9(24)& 0:00.95 326986 +2.81 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d8 Rb7-b8 Kd8-d7 Rb8-b7 Kd7-e6
Rb7-b6 Ke6-f7 Rb6-c6 c3-c2
9(24). 0:01.05 362041 +2.81 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d8 Rb7-b8 Kd8-d7 Rb8-b7 Kd7-e6
Rb7-b6 Ke6-f7 Rb6-c6 c3-c2
10(25)+ 0:01.53 562558 +3.16 Rb3xb2 (Rd2xb2) (c4-c3) (Rb2-b6) (Kf6-e7)
(Rb6-b7) (Ke7-d8) (Rb7-b8) (Kd8-c7)
(Rb8-b1) (c3-c2)
(Rb1-c1) (Kc7-d8) (e3-e4) (d3-d2)
10(26)& 0:02.02 777361 +3.71 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d8 Rb7-b8 Kd8-c7 Rb8-h8 c3-c2
Rh8xh7 Kc7-d6 Rh7-h8 c2-c1Q Rh8-d8
(Kd6-c7)
10(26). 0:02.05 794246 +3.71 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d8 Rb7-b8 Kd8-c7 Rb8-h8 c3-c2
Rh8xh7 Kc7-d6 Rh7-h8 c2-c1Q Rh8-d8
(Kd6-c7)
11(31)& 0:03.55 1404193 +3.90 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d6 Rb7-b6 Kd6-c5 Rb6-h6 c3-c2
Rh6xh7 d3-d2 Rh7-c7 Kc5-d6 Rc7xc2 d2-d1Q
Rc2-e2
11(31). 0:03.69 1463277 +3.90 Rb3xb2 Rd2xb2 c4-c3 Rb2-b6 Kf6-e7
Rb6-b7 Ke7-d6 Rb7-b6 Kd6-c5 Rb6-h6 c3-c2
Rh6xh7 d3-d2 Rh7-c7 Kc5-d6 Rc7xc2 d2-d1Q
Rc2-e2
12(31)+ 0:05.95 2450908 +4.25 Rb3xb2 (Rd2xb2) (c4-c3) (Rb2-b6) (Kf6-e7)
(Rb6-b7) (Ke7-d6) (Rb7-b6) (Kd6-c5)
(Rb6-h6) (c3-c2)
(Rh6xh7) (Kc5-c4) (Rh7-c7) (Kc4-b3)
Richard.
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