Author: Sune Fischer
Date: 03:19:22 05/28/02
Go up one level in this thread
On May 28, 2002 at 05:22:12, Georg v. Zimmermann wrote: > >>Oh, remembered what the problem was - the extensions! >>I also need to put a limit on the number of extended plies. >>So the margin should be: 1 ply per piece (for the qsearch) > >-2 for kings of course :) >and added to that the >>maximum extension depth. Last one is a limit many programs has, not a bad idea >>either, for searching 60 plies there could be many checks (which is also why I >>saw one case of depth 71, no way qsearch could go 11 plies with just two pawns). > >The problem here is that you set the memory for your arrays at startup. And >there you have to expect say highest search depth 40+ 30 pieces quiesce + 40 >extensions. I am no low level expert. But loads of arrays[110] must make it >slower because these are memory regions in between that are almost never used. This a problem everyone has (AFAIK), there are two way to solving it that I can think of. 1) put a check into the loops and return if maxply exceeded 2) stop the search at some point and leave a good safety buffer Neither method is good coding style IMHO. But I prefer using abit of extra memory (~150 kB) to get that speedup (1 less "if" per node). Frankly I'm not worried about being cache inefficient, because I only have 1 global pv array "PV pv[MAXPLIES]", about 150 kB in the end of that array is just the safety buffer, there is no data I need to access inbetween. These dayes 150 kB is nothing, I feel I can afford it better than an "if" that's wasted 99.99% of the time. Some may dislike it because there is a theoretic posibility of a crash (we all know Murphy's:), but it's really plague or colera. Maybe I'll change it later, you never know...:) >> >>If the number of estimated pieces is not sat too low, then this should be >>foolprof, right? > >Chess program and foolproof ? oh my :) Well I can't speak for others ;) -S. >Georg
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.