Author: James Robertson
Date: 18:44:44 09/24/98
Go up one level in this thread
On September 24, 1998 at 21:36:30, John Coffey wrote: >On September 24, 1998 at 21:12:46, Robert Hyatt wrote: > > >>You are overlooking a serious issue... the tree search grows *exponentially* >>with depth. Which means that any effort expended to order the best move >>first at any ply will greatly pay off in reduced tree search space. No >>matter how deep in the tree it is, capture or regular search. With alpha/ >>beta, move ordering is not just an issue, it is *the* issue. You can >>*easily* make your tree 10X larger with sloppy move ordering, and you will >>be faster than everyone in terms of NPS, but you will be searching 2-3 >>plies less deeply than everyone else. It is the *depth* and not the *NPS* >>that is important... > > >No I understood this issue. I am just asking if there is a dimished return, >say in an N ply search the last 2 to 3 ply (N-1, N-2 or even N-3) then the move >ordering would not seem to me to be worth the cost. > >john My experience with three completely different programs I have written (in Basic and C++)is that move ordering is critical right up to N-1. However, this is if you don't have a Q-Search; in my latest program (which does have a Q-search) move ordering is the single most important factor (with alpha-beta), and I use it right up to the last ply of the Q-search... James
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.