Author: Bernhard Bauer
Date: 04:10:46 01/19/98
Go up one level in this thread
Hallo,
I want to add some numbers to the hash table discussion.
This applies only? to Crafty.
Since the Fine position No 70 heavily depends on a hash table,
I use this well known posuition. The hash table sice varies
from the min of 64 kb up to 24 Mb.
Crafty v14.4
White(1): egtb 0
White(1): time cpu
White(1): sd 31
search depth set to 31.
White(1): hashp 640k
pawn hash table memory = 640K bytes.
+---+---+---+---+---+---+---+---+
8 | | | | | | | | |
+---+---+---+---+---+---+---+---+
7 | *K| | | | | | | |
+---+---+---+---+---+---+---+---+
6 | | | | *P| | | | |
+---+---+---+---+---+---+---+---+
5 | *P| | | P | | *P| | |
+---+---+---+---+---+---+---+---+
4 | P | | | P | | P | | |
+---+---+---+---+---+---+---+---+
3 | | | | | | | | |
+---+---+---+---+---+---+---+---+
2 | | | | | | | | |
+---+---+---+---+---+---+---+---+
1 | K | | | | | | | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
White(1): setboard 8/k7/3p/p2P1p/P2P1P///K w
White(1): d
White(1): d
hash depth time score trans/ref pawn used w used b nps
64k 31-> 34.82 2.85 79% 99% 98% b96% 109889
96k 31-> 23.34 3.04 53% 99% 99% b98% 125695
192k 31-> 25.12 3.04 66% 99% 99% b98% 122916
384k 31-> 17.73 3.02 74% 99% 99% b98% 126340
768k 31-> 9.85 3.25 90% 99% 99% b98% 125667
1.5M 31-> 6.50 3.25 121% 99% 79% b92% 126525
3M 31-> 3.17 3.25 136% 99% 27% b37% 123640
6M 31-> 34.66 2.85 79% 99% 98% b96% 110491
12M 31-> 34.25 2.85 82% 99% 88% b83% 109862
24M 31-> 36.02 2.85 84% 99% 68% b62% 110227
As we might espect, the solution time decreases as the hash table size
increases. However, after reaching a min of 3.2 sec the solution time
jumps up by a factor of 10!
So it looks like there is an optimal hash size, at least for Crafty
and this problem. The solution move Kb1! is found on ply 19 for a
hash table size of 3M. For a hash table size of 24M Crafty needs 26
plies.
My be there is something unclear for Crafty?
Are there similar results available for other programs?
Kind Regards
Bernhard
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