Author: Tim Foden
Date: 08:02:05 05/30/03
Go up one level in this thread
On May 30, 2003 at 10:46:41, Robert Hyatt wrote: >On May 29, 2003 at 07:33:59, Omid David Tabibi wrote: > >>On May 29, 2003 at 00:17:14, Robert Hyatt wrote: >> >>>On May 28, 2003 at 14:59:57, Uri Blass wrote: >>> >>>>I am too lazy to look at the source code of crafty to try to find what >>>>formula is used by crafty for reducing the distance between the kings in >>>>endgames like KQ vs KR to help it to win without tablebases. >>>> >>>>what is the formula that is used. >>>>I decided to try something in movei and first tests suggest that it is slightly >>>>productive but I want also to know what crafty does. >>>> >>>>Uri >>> >>> >>>Distance is easy: >>>max(abs(rankwhiteking-rankblackking),abs(filewhiteking-fileblacking) >>> >>>#define FileDistance(a,b) abs(File(a) - File(b)) >>>#define RankDistance(a,b) abs(Rank(a) - Rank(b)) >>>#define Distance(a,b) Max(FileDistance(a,b),RankDistance(a,b)) >>> >>>I use the three #defines above... >> >>In Image Processing, assuming that a and b are two pixels, >>Max(FileDistance(a,b),RankDistance(a,b)) is called "chess distance" :) > > >In graph theory it is often called "taxicab distance" since taxis have to >follow streets rather than "as the crow flies". :) I thought taxi distance would be (FileDistance(a,b) + RankDistance(a,b)), not Max(FileDistance(a,b), RankDistance(a,b)). Cheers, Tim.
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