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Subject: Re: Smarter programs not bigger TBs

Author: blass uri

Date: 00:19:05 04/14/00

Go up one level in this thread


On April 13, 2000 at 20:56:19, Robert Hyatt wrote:

>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.

I did not suggest to change things about 3 vs 2 endgames but only about 4 vs 1
endgames.

I do not know about cases when program cannot find the right move by search in
positions like KPPP vs K

Uri



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