6-men (64 bit) Nalimov EGTB generator

[Gian-Carlo Pascutto]

Hi GCP,

Great work!! Question, will this generator generate the stat files that were customary with Eugenes generator?

Thanks

Yes, but see the remarks above, there still seem to be some issues with it.

[vb4]

Hi GCP,

Yes I read them but have faith in you <S>.

BTW when all is working well will the generator be able to do the 5-1 EGTB's??

Thanks

[rjgibert]

You could be reading and writing to disk at least 3 times faster using an SSD. They are cheap enough to be affordable now and are well worth every penny given the performance improvement they have to offer.

[frankp]

Did anyone find a corrected version of this code. I was enjoying stressing my machine, but (as GCP noted) it producing bad data for some files.

Did Eugene ever release the six man code?

[Juan P. Naar]

Sorry for bumping such an old thread, but I would like to revive this topic because of the following reasons:

1) The 1 vs 5 sets were never generated
2) The main 6 piece TB distributors:
https://kirill-kryukov.com/chess/tablebases-online/
http://tablebase.sesse.net/

are missing the following .nbb files:

kbbkbb.nbb.emd
kbnkbn.nbb.emd
knnknn.nbb.emd
kppkpp.nbb.emd
kqbkqb.nbb.emd
kqnkqn.nbb.emd
kqqkqq.nbb.emd
kqrkqr.nbb.emd
krbkrb.nbb.emd
krnkrn.nbb.emd
krrkrr.nbb.emd

(only the .nbw files are uploaded)

A working 6 men Nalimov generator would be great to have.

[Ajedrecista]

Hello Juan Pablo:

Sorry for bumping such an old thread, but I would like to revive this topic because of the following reasons:

1) The 1 vs 5 sets were never generated
2) The main 6 piece TB distributors:
https://kirill-kryukov.com/chess/tablebases-online/
http://tablebase.sesse.net/

are missing the following .nbb files:

kbbkbb.nbb.emd
kbnkbn.nbb.emd
knnknn.nbb.emd
kppkpp.nbb.emd
kqbkqb.nbb.emd
kqnkqn.nbb.emd
kqqkqq.nbb.emd
kqrkqr.nbb.emd
krbkrb.nbb.emd
krnkrn.nbb.emd
krrkrr.nbb.emd

(only the .nbw files are uploaded)

A working 6 men Nalimov generator would be great to have.

I also do not see kbpkbp.nbb.emd, knpknp.nbb.emd, krpkrp.nbb.emd and kqpkqp.nbb.emd at tablebase.sesse.net. Could be that sides with identical pieces (KXYkxy) have not got NBB files by design?

------------

A good exercise would be looking what NBW and NBB are. I found this guide:

https://chessdb.sourceforge.net/tutoria ... l_egtb.php

[...]

Nalimov tablebase format files have the extension ".emd". Actually they will end with the suffix "nbw.emd" for White-to-move tablebases, and "nbb.emd" for Black-to-move tablebases. It pays to have both the White to move and Black to move tablebase for a particular material constellation (e.g. "krpkr.nbw.emd" and "krpkr.nbb.emd") for complete information whichever side is to move.

You may find a Nalimov tablebase file with the suffix ".nbw" or ".nbb" with no ".emd". This is an uncompressed tablebase, which is usually huge compared to its compressed (.emd) equivalent. It is far better to get the compressed tablebases, since they are much smaller and just as fast to access.

------------

It is true that I find both NBB and NBW files for kqkq, krkr, kbkb, knkn and kpkp at tablebase.sesse.net, apparently busting my hypothesis. Then, I found this:

http://www.horizonchess.com/FAQ/Winboard/egtb.html

[...] Earlier versions of Nalimov's code need the .nbw and .nbb of symmetrical endgames.

Which reinforces my opinion because those 4-man symmetric EGTB are from 2005, while the 6-man symmetric EGTB are from 2008.

------------

Additional info:

https://en.chessbase.com/post/fritz-end ... 3-part-1/7

[...]

Let's look at an example, which will also allow us a look at the file naming convention of the tablebases. Tablebase files always end in .emd, but you'll also see a string of letters before the .emd extension. You'll see something which looks like this:

kqbkn.nbb.emd

or

kqbkn.nbw.emd

There are two parts of these file names you need to be concerned about. The first string of letters (to the left of the first dot) tell you the material balance covered by the contents of the file. In both of the above cases the material balance is King + Queen + Bishop vs. King + Knight. So why are there two of these files? There needs to be one for each player (White and Black), and that's what the second string of characters (between the dots) tells you. The letter immediately to the left of the second dot tells you which side has the material advantage. So in the case of the file kqbkn.nbb.emd, Black is the player with the Queen and Bishop, while kqbkn.nbw.emd indicates that the White player has the Queen and Bishop.

This distinction becomes important when you're manually copying files (due to limited disk space available) instead of using the installation program. If you're copying a file like kqbkr.nbb.emd, you don't need to worry about copying any other five-piece files since no pawns are involved. But you do need to make sure to copy all of the sub-endgames which Queen + Bishop vs. Rook can simplify to due to material captures. If you don't, the five-piece file won't be able to automatically switch to the proper four-piece file and you'll end up with bum information. So you also need to copy:

Queen vs. Rook
Bishop vs. Rook
Queen + Bishop vs. King
Queen vs. King
Bishop vs. King
King vs. Rook (in the unlikely event that the Queen and Bishop get blundered away)

in order to be sure that the original five-piece file will have access to simplified material and will provide correct information.

[...]

Regards from Spain.

Ajedrecista.