Author: Stuart Cracraft
Date: 09:52:55 10/23/04
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On October 23, 2004 at 00:19:00, Robert Hyatt wrote: >On October 21, 2004 at 23:47:40, Stuart Cracraft wrote: > >>On October 21, 2004 at 22:49:28, Mathieu Pagé wrote: >> >>>I just read this paper by Robert Hyatt on rotated bitmap: >>> >>>http://www.cis.uab.edu/info/faculty/hyatt/bitmaps.html >>> >>>It describe how to generate attack_to[] and attack_from[] bitmaps. I think those >>>tables are not updated incrementaly and are computed from scratch at each node. >>>Am I right, or is there a efficient way to do it incrementaly ? >>> >>>Moreover, it seem to me that attack_to should be computed "on demand" only, >>>since we will probably not use every square of it. So it could be a function : >>>attack_to(int sq). Does this make sense ? >>> >>>Mathieu Pagé >>>mathieu.page at gmail dot com >> >>I don't know anything about Bob's URL but incremental updates should >>only require work on some of the pieces. >> >>Bob has made homage to Slate/Atkin of Chess 3.x/4.x at inception of his Crafty >>effort as I recall from another writing. >> >>I sure hope it is incrementally updated since having taken only the >>64-bit part of Slate/Atkin wouldn't be the whole enchilada. If he decided >>not to do incremental updates, I'd be curious what he calculated the cost >>factor of doing so vs. not doing so to be. > >The non-incremental version was 4x faster. That was what led me to the concept >of "rotated bitmaps". The incremental cost was way too high. > >version 6.0 of crafty threw out the incremental stuff and was the first rotated >bitmap program around... > Thanks for the history and statistic. > >> >>A quick search of Crafty's main.c reveals minimal mention >>of the word "incremental"... >> >>Too bad and I liked Chess 0.5 in Byte too. Never got it working though. >>Regrettable that those giant monster's Chess 4.x and NuChess aren't around even >>in their grotesque Fortran. Where did Slate and Atkin disappear to anyway? >> >>Stuart
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