Author: Eugene Nalimov
Date: 11:44:19 04/02/04
Go up one level in this thread
On April 02, 2004 at 14:33:23, Anthony Cozzie wrote: >On April 02, 2004 at 14:09:33, Eugene Nalimov wrote: > >>On April 02, 2004 at 13:43:31, Anthony Cozzie wrote: >> >>>On April 02, 2004 at 13:16:24, Vincent Diepeveen wrote: >>> >>>>On April 01, 2004 at 21:15:43, Dann Corbit wrote: >>>> >>>>>On April 01, 2004 at 20:40:58, Eugene Nalimov wrote: >>>>> >>>>>>On April 01, 2004 at 19:05:09, Dann Corbit wrote: >>>>>> >>>>>>>On April 01, 2004 at 18:38:59, Sune Fischer wrote: >>>>>>> >>>>>>>>On April 01, 2004 at 18:29:27, Dann Corbit wrote: >>>>>>>> >>>>>>>>>On April 01, 2004 at 17:59:38, Eugene Nalimov wrote: >>>>>>>>> >>>>>>>>>>On April 01, 2004 at 15:16:34, Marc Bourzutschky wrote: >>>>>>>>>> >>>>>>>>>>>The Chessmaster format is indeed better >>>>>>>>>> >>>>>>>>>>What does it mean "better"? :-) >>>>>>>>>> >>>>>>>>>>It stores less information, thus compresses better. >>>>>>>>> >>>>>>>>>I have an idea that I think would be helpful if you should be so kind as to >>>>>>>>>perform it. >>>>>>>>> >>>>>>>>>Write a scanner that reads your wonderful EGTB files and spits out a two bit >>>>>>>>>state only for each position (won/lost/drawn/broke) to create bitbase files. >>>>>>>>> >>>>>>>>>The reason I suggest it is that a bazillion programmers won't have to reinvent >>>>>>>>>the wheel. >>>>>>>>> >>>>>>>>>I suggest the use of the bitbase files early in the search (completely pulled >>>>>>>>>into ram) and then EGTB at the leaves if the bitbase indicates it is worthwhile. >>>>>>>> >>>>>>>>You must mean it the opposite way, bitbases at the leaves and EGTBs a near root? >>>>>>>> >>>>>>>>I think it would be better to use bitbases in the entire search and only use >>>>>>>>full EGTBs when the position is at the root. >>>>>>>> >>>>>>>>Or, if you want the search to eventually return mate scores, probe EGTBs when >>>>>>>>bitbases say it is won and beta>=mate_bound or bitbases says it lost and >>>>>>>>alpha<=-mate_bound. >>>>>>>>Perhaps probing directly into EGTBs when window allows it would be faster, >>>>>>>>matter of tuning of course. >>>>>>> >>>>>>>I guess I had not thought about it carefully enough. I imagined using bitbases >>>>>>>to get a won/lost/drawn opinion (at all nodes). But unless you know the exact >>>>>>>value of the leaves, I don't see how you can choose the best move. >>>>>>> >>>>>>>I imagined something like this: >>>>>>>If the best evaluation is drawn or lost, who cares. Do whatever move is among >>>>>>>the suggested list. >>>>>>>If the best evaluation is won, then: >>>>>>>Examine the bottom leaves that are won and perk the correct values back up. >>>>>>> >>>>>>>How will we otherwise find the true value? I am afraid I don't understand how >>>>>>>it can work. >>>>>> >>>>>>In my "TODO" list. But let me finish 6-men TBs first... >>>>>> >>>>>>Simple way is to keep both w/d/l and full tables. You need to probe full table >>>>>>only when position is OTB. Otherwise you probe w/d/l table. W/d/l tables are >>>>>>smaller, and relevan ones can be always loaded to RAM, so you can probe them >>>>>>everywhere in the search, including Q-search. >>>>>> >>>>>>Probing of the full TBs can be much slower than it is now, probably ~1 sec >>>>>>should be fine. In theory that allows to use better decompression algorithm. >>>>>> >>>>>>And you don't need 2 bits per position. 1.6 bits are enough (5 positions per >>>>>>byte). >>>>> >>>>>How about an interface to your EGTB system that takes a standard EPD string as >>>>>input? >>>> >>>>The problem is that everyone must first post onto CCC to get permission to use >>>>his code. Email he never answers until there is a posting onto CCC. Only from 1 >>>>american author i know he got directly permission at his first email. The others >>>>after half a year or so post onto CCC and only then get an answer. >>>> >>>>So your only problem is not the EPD, but the legal permission for each user to >>>>use that program, even if it is put at a commercial cdrom. >>>> >>>>As shipping an email will not get answerred. I have not heard a single european >>>>programmer so far who got permission by email within 6 months. >>>> >>>>>That way, it would be really simple for people to interface to it that have not >>>>>already done so. Just about every chess program has a "convert board position >>>>>to EPD" function of some kind. >>> >>> >>>Hmm, actually that is true. I've emailed Nalimov 2-3 times asking for >>>permission to use the EGTB code with no answers so far. >>> >>>anthony >> >>According to my archive I replied on 7/11/2003. >> >>Thanks, >>Eugene > >Which address did you reply to? (@andrew, @earthlink, @sparta, @verizon) ? And >what was the date of the email you replied to? > >I gave up on my andrew account this summer. For amusement I checked it today. >4,400 messages, all spam :) Maybe that would explain the mystery . . > >anthony acozzie-at-andrew-dot-cmu-dot-edu Thanks, Eugene
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