Author: Andrew Dados
Date: 10:52:54 11/14/00
Go up one level in this thread
On November 14, 2000 at 13:19:17, paul bedrey wrote: >What happens when ponder is disabled? Does hash table still get created? Are >there limitations to hash size? Does primary and secondary cache size influence >hash? What happens when the program exceeds the aloted hash size? Are there any >formulas for determining the optimal size of hash? How significantly does hash >influence program strength? I know I ask too many questions but you should hear >my kids! > >Thanks > >Paul 1. Hash table is huge table in memory when all visited positions are stored to avoid recomputing transposed positions and keep found moves for future computing. Pondering is thinking on opponents time and has nothing to do with hashtable (or very little). So hash table is still created/used with pondering disabled. 2. The limit for hashtable size is ram (computer memory) size. If hash table is too big that it does not fit in physical memory, then it gets swapped to 'virtual memory', which is hard drive, and then program slows down to crawl. 3. Optimal hash table size cam dependent on many things like ram size, time control of the game, operating system and program itself. Roughly it can be set to 1/2 of computers RAM if only one chess program is running on the computer; if you match 2 programs you may try giving 1/4 of RAM to each program. 4. In middle game hash table gives speedup of about 50% which can be translated to something like 50-60 elo in strength. In endgame hash table is far more important and can give tremendous speedup (like 5-10x). All of the above depends highly on a position, ways program uses hash table and other factors... -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.