Author: Andrew Williams
Date: 03:29:31 01/12/02
Go up one level in this thread
On January 11, 2002 at 11:44:39, David Rasmussen wrote:
>[D]2Q2n2/2R4p/1p1qpp1k/8/3P3P/3B2P1/5PK1/r7 w - - 0 1
>
>In the above position, my search tree explodes because of extensions. It takes >
>3 minutes and 42 million nodes to finish an 8 ply search. How does your program
>do?
>
>Any good ideas on how to limit extensions in such a position.
>
>P.S. Solving the position is no problem. It is a simple mate in 5 plies, and is
>found very early on at depth 1 or 2 or so. Still, there must be something
>unsound about my extensions, or at least room for improvement, when this
>position makes the tree explode.
>
>/David
Mine keeps track of the number of extra plies each type of extension causes.
Occasionally I get a problem like yours and I use this information as a starting
point for my investigation:
1> 5 0 6 1.f3
1b 7 0 12 1.f4
1= 79 0 107 1.f4
2> 79 0 112 1.f4
2= 79 0 159 1.f4
SCRUBBING TT: -121 [1392] 279
3> 79 0 205 1.Qxf8 Qxf8 2.Rxh7
3= 1684 0 405 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qxd6
4> 1684 0 413 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qxd6
SCRUBBING TT: 1484 [+Mnear] 1884
4= +M03 0 798 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Rg7 Kh5 4.Qh8
5> +M03 0 945 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
5= +M03 0 1820 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
6> +M03 0 1828 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
6= +M03 0 6044 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
7> +M03 0 6052 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
7= +M03 0 32064 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
8> +M03 0 32072 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
8= +M03 1 130318 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
9> +M03 1 130326 1.Qxf8 Kh5 2.Rxh7 Kg4 3.Qg7
NODES per second 130600
NODES: ab: 198798 q: 193138 tot: 391936
TT PERFORMANCE
probes: 582150 hits: 101587 cutoffs: 39259 secondary: 17250 entries:
142010 replacements: 51539 too far: 47 (0%)
probes: 148% hits: 17% cutoffs: 38% secondary: 16%
NULL MOVE: attempts: 51235 cutoffs: 51229 (99%)
CUTOFFS: first move: 73681 later: 14 (99%)
PAWN TT: probes: 544739 hits: 523140 (96%)
EXTENSIONS: checks: 59228 srtc: 22608 recaptures: 684 pushes: 4
promotes: 0 mate: 0 null: 0
DEPTHS: main: 39 qsearch: 39
EGTB: probes: 0 hits: 0 (hit-rate: 0%)
Andrew
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.