Author: Dr. Gregor Overney
Date: 17:43:25 11/20/98
Go up one level in this thread
On November 20, 1998 at 00:47:46, James Robertson wrote:
>On November 19, 1998 at 22:34:09, James B. Shearer wrote:
>
>> I was playing a Crafty clone on ICC and the following position arose:
>>
>>setboard r5k1/ppp1Q2p/1q4p1/8/8/2P1B3/bP4P1/4R1K1 b - - 0 24
>>
>>The clone played qb6xb2 which loses quickly after be3-d4. I checked the
>>position after the game was over with crafty 15.15 on my k6-233. Crafty seems
>>to take an inordinate amount of time to reject qxb2 (over 100 seconds). Every
>>other program I have (cm5500, rebel8, rebel decade20, fritz4) either never
>>considers qxb2 or rejects it quickly (under 1 second). Is this a bug?
>> James B. Shearer
>
>Perhaps a null move problem (unlikely)? The mate is at ply 12 although Black
>should realise that it loses it's queen (even if it doesn't see the mate) by ply
>8. Ply 8 is when Crafty finds 1. ... c5 (after 28 seconds on my P233). GnuChess
>is another program that has problems with this position.
>
>James
c5 on ply 8? My version of Crafty seems not to suggest c5 at ply 8 (but a Qd6).
If Black plays a Qxb2, Crafty finds the Bd4 for White very quickly. The
following is my Crafty 16.1 output (compiled without fastcall and therefore 15%
slower than my "old" 15.20 version):
EPD Kit revision date: 1996.04.21
hash table memory = 24M bytes.
pawn hash table memory = 5M bytes.
EGTB cache memory = 10M bytes.
EGTB access enabled
using tbpath=./TB
5 piece tablebase files found
Crafty v16.1 (1 cpus)
White(1): hash 80m
hash table memory = 48M bytes.
White(1): hashp 32m
pawn hash table memory = 20M bytes.
White(1): mt 2
max threads set to 2
White(1): analyze
Analyze Mode: type "exit" to terminate.
clearing hash tables
book moves {e4, d4}
book 0.0s 0% e4!
analyze.White(1): setboard r5k1/ppp1Q2p/1q4p1/8/8/2P1B3/bP4P1/4R1K1 b - - 0 24
setboard r5k1/ppp1Q2p/1q4p1/8/8/2P1B3/bP4P1/4R1K1 b - - 0 24
clearing hash tables
time surplus 0.00 time limit 30.00 (3:00)
depth time score variation (1)
starting thread 1
5 0.07 2.76 1. ... Qxb2 2. Bd4 Bf7 3. Qxc7 Bd5
5-> 0.12 2.76 1. ... Qxb2 2. Bd4 Bf7 3. Qxc7 Bd5
6 0.14 -- 1. ... Qxb2
6 0.23 2.31 1. ... Qxb2 2. Bd4 Bf7 3. Qxc7 Qd2
4. Re7
6-> 0.34 2.31 1. ... Qxb2 2. Bd4 Bf7 3. Qxc7 Qd2
4. Re7
7 0.95 -- 1. ... Qxb2
7 1.36 1.56 1. ... Qxb2 2. Rd1 Qe2 3. Rd8+ Rxd8
4. Qxd8+ Kf7 5. Qxc7+ Ke6 6. Qc8+ Ke5
7. Bxa7
7-> 2.46 1.56 1. ... Qxb2 2. Rd1 Qe2 3. Rd8+ Rxd8
4. Qxd8+ Kf7 5. Qxc7+ Ke6 6. Qc8+ Ke5
7. Bxa7
8 4.95 -- 1. ... Qxb2
8 7.95 -6.43 1. ... Qxb2 2. Bd4 Qxg2+ 3. Kxg2 Bd5+
4. Kh3 Bf7 5. Qxc7 a5 6. Qxb7 Rd8
8 12.64 ++ 1. ... Qe6!!
8 13.34 0.36 1. ... Qe6 2. Bd4 Qxe7 3. Rxe7 c5 4.
Bxc5 b6 5. Bd6 Bd5
8 15.90 0.61 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bd5
4. Ra5 Bc4 5. Bxa7 Kg7
8-> 16.00 0.61 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bd5
4. Ra5 Bc4 5. Bxa7 Kg7
9 17.11 0.62 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bc4
4. Rxa7 Rxa7 5. Bxa7 Kf7 6. Kf2 Ke6
9-> 22.14 0.62 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bc4
4. Rxa7 Rxa7 5. Bxa7 Kf7 6. Kf2 Ke6
10 24.01 0.52 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bc4
4. Rxa7 Rxa7 5. Bxa7 Kf7 6. Kf2 Ke6
7. Bd4
10-> 31.87 0.52 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bc4
4. Rxa7 Rxa7 5. Bxa7 Kf7 6. Kf2 Ke6
7. Bd4
11 36.76 0.56 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bc4
4. Rxa7 Rxa7 5. Bxa7 Kf7 6. Kf2 Ke6
7. Bd4 Bd3
11-> 54.01 0.56 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bc4
4. Rxa7 Rxa7 5. Bxa7 Kf7 6. Kf2 Ke6
7. Bd4 Bd3
12 1:35 0.60 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bd5
4. Ra5 Re8 5. Bf4 Bc6 6. Rxa7 Re2 7.
g3 Kf7
12-> 2:17 0.60 1. ... Qd6 2. Qxd6 cxd6 3. Ra1 Bd5
4. Ra5 Re8 5. Bf4 Bc6 6. Rxa7 Re2 7.
g3 Kf7
13 3:15 0.55 1. ... Qd6 2. Qxd6 cxd6 3. Rd1 Kf7
4. Rxd6 Be6 5. Kf2 Bf5 6. Bg5 Re8 7.
c4 Rc8 8. Rd4
13-> 5:41 0.55 1. ... Qd6 2. Qxd6 cxd6 3. Rd1 Kf7
4. Rxd6 Be6 5. Kf2 Bf5 6. Bg5 Re8 7.
c4 Rc8 8. Rd4
14 7:36 0.54 1. ... Qd6 2. Qxd6 cxd6 3. Rd1 Kf7
4. Rxd6 Be6 5. Kf2 Bf5 6. Bg5 Re8 7.
Rf6+ Kg7 8. Rd6 h6 9. Bf4
new 14 8:15 2/32 1. ... Qb5
Black(0): new
analyze.Black(1): clearing hash tables
book moves {e4, d4}
book 0.0s 0% e4!
analyze.White(1): exit
exit
analyze complete.
Gregor
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