Author: Dann Corbit
Date: 18:15:43 04/01/04
Go up one level in this thread
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? 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.
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.