Author: Vasik Rajlich
Date: 15:42:44 06/16/05
Go up one level in this thread
On June 16, 2005 at 13:31:39, Vincent Diepeveen wrote: >On June 16, 2005 at 05:22:26, Vasik Rajlich wrote: > >>On June 15, 2005 at 22:40:22, Tor Alexander Lattimore wrote: >> >>>Hi >>>Is it possible to use a single variable in the MTD(f) search? Something like >>>this: >>> >>>int MTD(int depth, int guess) >>>{ >>> if (depth<1) return Evaluate(); >>> MOVE move_to_search; >>> int best=-INFINITY; >>> GenMoves(); >>> while (GetNextMove(&move_to_search)) >>> { >>> PlayMove(move_to_search); >>> val = -MTD(depth - 1, -guess + 1); >>> UnPlayMove(move_to_search); >>> if (val>best) >>> { >>> best=val; >>> if (val>=guess) >> >>You missed a line here. Fail-hard is "return guess", fail-soft is "return val". >> >>Fail soft helps when you need to re-search, so it helps more in MTD (f) than >>PVS, and doesn't matter at all in pure alpha-beta. > ^^^^^^^ >I guess you meant a small typo here. doesn't ==> does > Actually I just forgot about hash effects at the next iteration. Without those, the statement would be true .. (as far as I can see) Vas >> >>Vas >> >>> } >>> } >>> return (best); >>>} >>> >>>perhaps there is something very wrong with this? or perhaps it's used already, I >>>just noticed that on Aske Plaat's site he always uses an Alpha-Beta search with >>>0 width windowed searches, but doesn't this do the same thing? Is using >>>fail-soft type algorithms used in MTD(f) since it could well help zoom into the >>>correct score sooner? >>> >>>Cheers >>>Tor
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