Author: José Carlos
Date: 05:42:52 05/28/02
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On May 28, 2002 at 06:19:22, Sune Fischer wrote: >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. Just out of curiosity, how much slower is your program with the "wasted if"? Did you measure it? José C. >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
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