Author: martin fierz
Date: 01:35:42 03/26/03
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On March 25, 2003 at 17:58:33, Eugene Nalimov wrote: >On March 25, 2003 at 17:30:52, martin fierz wrote: > >>i computed some checkers endgame databases with retrograde analysis based on the >>paper by the chinook team. for larger databases, i have a memory size problem; >>specially as win32 only allows a process to use 2GB. >>i once heard that it was possible to compute a win/loss/draw endgame database >>using only 1 bit per position as opposed to 2 bits as i was using up to now (and >>like in the chinook paper). >> >>does someone here know more about this? i'm looking either for an explanation >>for dummies, or for a reference to a paper. >> >>thanks in advance >> martin > >Actually, you can force Windows NT/2k/XP to give your application 3Gb, not 2Gb. >Search for /3Gb switch at Microsoft web site. Application should be "clean", >i.e. it should not assume that high pointer bit is always zero. For such >applications you should specify linker flag /LARGEADDRESSAWARE. i know - but 2 or 3GB; it doesn't really matter. it's just a limitation that makes more memory-efficient algorithms necessary. >One more note: you probably will not be able to allocate 3Gb in one chunk, but >you'll be able to allocate 30 100Mb chunks. > >Of course you can use Win64 where you don't need those tricks :-) i'd like to but i don't have the $$$$ necessary for that. a win32 machine with 2GB ram is MUCH cheaper than a win64 machine with 2GB ram :-( >And now returning to the original question: with easily "reversable" index >function you need *random* access not to two bitmaps, but only to one. This way >you can generate first bitmap in memory, flush it to disk, generate second >bitmap, and then sequently walk through first bitmap using small (several >megabytes) buffer. umm, i asked for an explanation for dummies. this one is beyond me :-) do you have a reference to a paper where this is explained in more detail? cheers martin
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