Author: Robert Hyatt
Date: 17:56:19 04/13/00
Go up one level in this thread
On April 13, 2000 at 11:21:11, blass uri wrote: >On April 13, 2000 at 09:22:44, Robert Hyatt wrote: > >>On April 13, 2000 at 00:43:02, Dave Gomboc wrote: >> >>>On April 12, 2000 at 23:18:38, Robert Hyatt wrote: >>> >>>>On April 12, 2000 at 22:27:22, Dave Gomboc wrote: >>>> >>>>>On April 11, 2000 at 16:44:59, Robert Hyatt wrote: >>>>> >>>>>>On April 11, 2000 at 12:18:46, Jason Williamson wrote: >>>>>> >>>>>>>On April 11, 2000 at 09:31:51, Robert Hyatt wrote: >>>>>>> >>>>>>>>On April 11, 2000 at 03:07:48, Jouni Uski wrote: >>>>>>>> >>>>>>>>>On April 10, 2000 at 17:22:09, Arndra L. Sharp wrote: >>>>>>>>> >>>>>>>>>>On April 10, 2000 at 15:52:18, Robert Hyatt wrote: >>>>>>>>>> >>>>>>>>>>>On April 10, 2000 at 11:20:51, Arndra L. Sharp wrote: >>>>>>>>>>> >>>>>>>>>>>>First of all let me state that I am not a programmer, just someone who enjoys >>>>>>>>>>>>computer chess immensely. I have seen a lot of posts that put down the Endgame >>>>>>>>>>>>Turbo disks because they do not contain all of the TBs, in particular those TBs >>>>>>>>>>>>after the pawn queens. I think it a good idea to reduce the hard drive space >>>>>>>>>>>>required for TBs by pruning those TBs that any good chess program can figure out >>>>>>>>>>>>if its brain was not disabled. It seems the real problem is that those programs >>>>>>>>>>>>that use TBs turn off the permanent brain once the program is in a TB position >>>>>>>>>>>>and then the program gets confused if after a pawn queens and the now simple win >>>>>>>>>>>>(for good chess programs) is not in the TB folder. This is something that the >>>>>>>>>>>>programmers probably did not anticipate originally everyone has seen games where >>>>>>>>>>>>this impacts the result. Now that this has been identified, why can't the >>>>>>>>>>>>programmers tell their programs to follow the TB tree to pawn promotion and >>>>>>>>>>>>reset the permanent brain at that point. Many people have reported that the >>>>>>>>>>>>programs that blunder with missing 5 man TBs play the same ending fine with 3 >>>>>>>>>>>>and 4 man TBs. It just seems that the programs don't know how to think again >>>>>>>>>>>>after they start down a tree and the tree ends before checkmate. A bug fix by >>>>>>>>>>>>the programmers would be more preferable than taking up another 5 gigs of hard >>>>>>>>>>>>drive space. >>>>>>>>>>>> >>>>>>>>>>>>Arndra >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>>Crafty does this correctly. But with the price of disk drives, holding all the >>>>>>>>>>>3-4-5 piece files is now trivial... 40 gigs for 250 bucks is typical now. You >>>>>>>>>>>only need 8 gigs for _all_ the 3-4-5 piece files (compressed). >>>>>>>>>> >>>>>>>>>>Does anyone sell all the TBs on CDs? >>>>>>>>> >>>>>>>>>Try http://mitglied.tripod.de/ChessBits/index.html! They sell 10 CDs or one >>>>>>>>>harddisk for 3-5 piece. >>>>>>>>> >>>>>>>>>Jouni >>>>>>>> >>>>>>>> >>>>>>>>Unfortunately it isn't all the 3-4-5 piece files. They add up to almost 8 >>>>>>>>gigs compressed, which won't come close to fitting on 10 CDs... >>>>>>> >>>>>>>All the TB - the 6 piece ones from your site come to 7.05 gigs (7,580,368,539 >>>>>>>bytes). This is all the 5 piece ones correct? Or perhaps I missed a few... >>>>>> >>>>>> >>>>>>the 7.5 gigs is right... >>>>>> >>>>>>which won't fit on 10 cd rom disks... >>>>> >>>>>But it will fit on 3 or 4 DVD disks. Maybe Chessbase will use DVD if they print >>>>>another run of these in the future. All of the 3-4-5 piece databases would fit >>>>>on a single DVD. >>>>> >>>>>Dave >>>> >>>> >>>>I don't follow. I wasn't aware that a single DVD could hold almost 8 gigs, >>>>which is the total size of the 3-4-5 piece files (compressed). >>> >>>My mistake. I thought the 7.5 gigs included the six-piecers that had been >>>constructed. I obviously didn't read all of the quoted text carefully! :( >>> >>>DVDs hold 2.something gigs each, I think. So I guess it would take 3 or 4 DVD >>>disks just for the 3-4-5-piece databases. That seems reasonably doable. >>> >>>Dave >> >> >>The problem is that Eugene slipped in another 2 gigs of 5 piece files on my >>ftp site. We now have _all_ 5 piece files, including the 4 vs 1 configurations. >>Almost 8 gigs just for 5's now. I had not even noticed these until I copied >>the things over to one of the 8 quad xeons I have been playing with, and I >>wondered "why is this now 7.5 gigs when it was under 6?" I found out. :) > >4 vs 1 are the less important tablebases because I believe that programs can >always find the right moves by search without tablebases in 4 vs 1 endgames. > >It can save some space to use only win/draw tablebases without distance to mate >in 4 vs 1 endgames. > >Uri You will mis-evaluate lots of positions, if you start in a 5 piece file but trade into a position you have no database for. IE KNN vs KP has lots of wins, and lots of draws. Ditto for endings like KRP vs KR... without the 3/4 piece files you don't see that your opponent is trading into a drawn position or lost position when he was winning before, because you don't know how to evaluate the 4 piece files. If you are given a 4 piece ending to start with, you probably will win most of the winnable cases, even without the 4 piece files. But the transition from 5 to 4 becomes clumsy...
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