Author: Inmann Werner
Date: 06:24:00 06/30/98
Selective deepening and Hashtables Problem: In alpha.beta , there is a variable distance (distance to the horizon) , which is decreased each call of Alpha-beta. If you have, lets say for example, a check, you want to deepen the search. I do this by increasing The variable distance. If you insert the position in the hashtable, you write the variable distance in the hash table. (I do so). I only take hashtable entrys, where the distance in it is more than the actual distance. (why not?) If a search the move one ply deeper the next time (iterative deepening) and look at the hash table, the Position has a very good value of the variable distance because of the selective deepenings made in the Last search. Because the program knows nothing about the actual selective deepenings, which will come In the search it is satisfied and takes the hash entry. And thats the problem. The search nearly never looks really deeper in this move, because it takes it always fFrom the hash table until my search is deeper then all previous extensions. Is my problem-analysis ok? Have I forgot something important or stupid? If not, what can I do? Should I write the "distance - number of extensions" when I write to the Hash table? What follows then out of this!? Werner
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.