Author: Eugene Nalimov
Date: 11:09:33 04/02/04
Go up one level in this thread
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
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.