Author: Pham Hong Nguyen
Date: 23:37:38 04/26/99
I am trying to build a simple chess program. I use hash table following the
lecture “Strategy and board game programming” of UCI. Element of hash table is
defined:
typdef struct {
long checksum;
short depth;
enum {EXACT, LOWER_BOUND, UPPER_BOUND} entry_type;
short eval;
} hashtable;
I hope that it would save time as much as some one reported about 90%. But it
has saved only 30% at 7 ply (with quiescence search). Some data as following
(without Null move):
No hash:
number of evaluation: 18.160.786
Small hash table:
hash size (element): 64471
number of evaluation: 13.389.557
collision cases: 1.030.140
successful cases: 268.593
Big hash table:
hash size (element): 1.496.480
number of evaluation: 10.921.967
collision cases: 679.605
successful cases: 273.021
When I use hash table with Null move, it saves more 5% than Null move only.
My questions are:
- Is it normal or may I do some thing wrong?
- How may I do to improve?
Any help would be much appreciated.
Pham Hong Nguyen (sorry for my English)
(From Vietnam)
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