Author: Anthony Cozzie
Date: 11:33:23 04/02/04
Go up one level in this thread
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
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