Author: Tony Werten
Date: 01:50:49 11/10/03
Go up one level in this thread
On November 10, 2003 at 04:30:16, Uri Blass wrote: >On November 10, 2003 at 02:27:53, Tony Werten wrote: > >>On November 09, 2003 at 07:40:38, scott farrell wrote: >> >>>On November 09, 2003 at 04:55:40, Matthias Gemuh wrote: >>> >>>>On November 09, 2003 at 03:53:24, Daniel Shawul wrote: >>>> >>>>> >>>>> >>>>>>I do not remember if Ernst's paper said that you make the move first and then >>>>>>decide if it is futile. >>>>>> >>>>>>If it did, then it's definitely killing all the interest of futility pruning at >>>>>>depth 1! >>>>>> >>>>>>The idea is to prune before you make the move. So you stay at depth==1, look at >>>>>>the move, and say "hey, this move looks completely futile, let's ignore it!". >>>>>> >>>>>> >>>>>> >>>>>> Christophe >>>>> >>>>>A futile move is futile before you make or after you make it. >>>>> before >>>>> mat_bal + move_gain + margin < alpha => futile move >>>>> after >>>>> mat_bal + margin < alpha => futile move >>>>>Anyway my question is since you go directly to quiescent search >>>>>(where stand pat cutoff of all futile moves occur) after making the move, >>>>>we only saved ourselves "making of the futile moves".I can comprehend the >>>>>extended futlity pruning but not this.For me as long as standing pat cut off >>>>>is there , futility pruning at frontier is unnecessary,and if it is,it only >>>>>saves the time to make and unmake futile moves.Where does the 60% tree shrinkage >>>>>comes from?Please try to see where my proble is. >>>>> >>>>>Daniel >>>> >>>> >>>> >>>>Your logic seems sound for me. We seem to save only >>>>MakeMove() + UnmakeMove() + Evaluate(). >>> >>>I think you are wrong, you save: >>> >>>MakeMove() + UnmakeMove() +alphaBeta()+ qSearch()+ stand-pat+ Evaluate(). >>> >>>qsearch of course can be a few plies also. >> >>No, only when you were wrong. That's the whole point with futility pruning, it >>only saves nodes when you were wrong. >> >>Normal: Make move, goto quiescence, eval>beta, cutoff. go back, unmake move. >> >>pruning: "eval" <alpha, skip. >> >>You save 1 make move, 1 function call, 1 eval and 1 unmake move but never a >>node. > >It is because you have different definition of node than me. No, you have a different definition than us :) >I have nodes++ only when I make moves. > >Makemove is for me something expensive as I explained in another post. That wasn't really my point. My point was that if you count a skipped move the same as a made move, you should get the same count. The only time it is lower is when you were wrong. So you basicly can't search 60% less nodes though it's possible to spend 60% less time. Counting the skipped move seems logical, otherwise I have some more fantastic pruning algorithms with no sideeffects. "Never count positions on the last ply" is one of them wich saves over 70% of your nodes. Tony > >Uri
This page took 0.01 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.