Author: Vincent Diepeveen
Date: 10:04:58 01/09/02
Go up one level in this thread
On January 09, 2002 at 12:50:12, David Hanley wrote: >I have seen it claimed somewhere that with perfect move ordering, an eight ply >search would only consume a thousand nodes or so, even only alphabeta ( no >hashing or forward pruning ). > >Is this so? > >dave all chessprograms use nowadays nullmove. this means that you can do with very little nodes, depending upon evaluation. Suppose your evaluation is always returning 0, which makes ordering near perfect of course. suppose we order such that not a single extension gets triggered: h3 h6 g3 g6 f3 f6 e3 now we have to look at all nodes behind here. but for example R=3 at depth 2 how many nodes do we need to get a cutoff for other moves than h6? Let's give one example: h3 g6 nullmove <all moves> qsearch 1 2 3 4+R So for all moves at the second move we only need to search number of semi legal moves there for each possibility at 2 ply. that's like 20 posibilities x 30 = 600 nodes. In short real little to refute all moves at root+1 ply. This where without nullmove total number of nodes needed is gigantic compared to what nullmove needs.
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.