Author: Alvaro Jose Povoa Cardoso
Date: 03:38:49 04/11/02
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On April 11, 2002 at 04:15:34, martin fierz wrote: >On April 10, 2002 at 15:56:54, Alvaro Jose Povoa Cardoso wrote: > >>For checkers EGTBs I store only 'black to move entries'. >>For 'white to move' I reverse the board and exchange colors. >>Using 32bit bitboards I need to reverse (mirroring) the board bitboards and the >>exchange the colors. >> >>Thank you all, >>Alvaro Cardoso > >hi alvaro, > >have you written your own program by now or did you adapt mine? if you are doing >the second, then the answer to your question is "it's irrelevant" - and probably >the answer is the same if you wrote your own program... my generator took 5 >weeks on a XP1600+ with 1GB ram to build the 4-4 database (and anything >smaller). once you have this, you will never need to compute it again... another >point is that in spanish checkers, you should be much faster building the db, >because AFAIK kings sweep, and you have lots more captures which take you in >smaller databases much faster than in english checkers, i.e. the number of >passes per db you have to do should be much smaller. > >in the meantime, i have compressed my database, and am working on the access >code. believe me: this is the part you have to do right - not the db computation >itself. > >aloha > martin Hi Martin, nice to hear from you :) Unfortunately I didn't even started. I'm anxious to read the code you sent me. I have very litle time, since I work all day and get home very tired. But I'm very interested in solving this EGTB problem. My interest in 32bit reversing is because it will be used in the program search engine for 'white to move' positions. I agree it is not a great issue but if I can do it a little faster then I'll do it. Yes you are right about Spanish/Portuguese checkers greater number of captures. Martin, I red Jonathan Schaeffer's paper and I have doubts about resolving the non-capture positions (I think I didn't understood all of the algorithm). My (surely stupid) question is: When generating the tablebases we do have to make an alphabeta search for these non-capture positions don't we? (contrary to the capture positions in that we get the results from lesser piece databases). Also, in the engine I was planning to put all the 4 piece databases in memory and the others I read from disk. Do you think it is sensible? Best regards, Alvaro Cardoso
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