Author: Uri Blass
Date: 01:30:16 11/10/03
Go up one level in this thread
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. I have nodes++ only when I make moves. Makemove is for me something expensive as I explained in another post. Uri
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