CCRL Discussion Board

Yes, I think it is perfectly fine. I'm not sure what if anything I will actually download. I have here the chessbase "DVD Endgame Turbo 2" which has some 6 men tablebases on it. Presumably they are the most important ones - although this product is quite old now. Oh good, I've been wonder...

OK, thanks. It seems that a fully unsymmetric one (w.r.t. piece exchange) like KRBNKQ takes about 3GB after compression. That is only about a factor 3 compared to the 8GB an uncompressed 6-men would need. So your 20MB/sec is a bit optimistic at any rate. This is not a big issue, but KRBNKQ is 12.37...

Arpad - Thank you for the examples! That helps greatly to fix the idea.

john

Here is the link to my new site: http://kirill-kryukov.com/chess/egtb/files.html I'm doing a test right now, downloading kbbkn.nbb and kbbkn.nbw simultaneously. The typical rate is 95-105 KB/s. I've watched it drop to 60 and go as high as 150. It'll be a couple hours before I have an average downlo...

Well, like I said, HD speeds of 50MB/s are more or less standard now, so if building an EGTB takes 50 cycles, and each cycle a read and a write of the complete EGTB, that makes the generation 100 times slower. So if I will not reach a generation speed of 500KB/sec, I will have done a bad job. A gen...

Here is the link to my new site: http://kirill-kryukov.com/chess/egtb/files.html I'm doing a test right now, downloading kbbkn.nbb and kbbkn.nbw simultaneously. The typical rate is 95-105 KB/s. I've watched it drop to 60 and go as high as 150. It'll be a couple hours before I have an average downlo...

If you refer to "http://" peers in eMule, then those are just ordinary users who just didn't care to pick a name. Also there are no central distribution nodes in eMule. You mean that when I see a user name of http://emule-project.net it's actually an anonymous user too chicken to put down...

It is universally accepted that in this case there is no "dual" in the study. So that's why the Effective Unique Move Sequences (EUMS) are important. I'm unfamiliar with that term. What is meant by a "dual"? Also, do you have an example of an EUMS with a cycle to be avoided? Per...

By the way, what kind of download speeds can someone expect from emule when starting Nalimov collection for the first time? The peak rates I saw were 120-150 KB/s -- a number limited by the supply of donors, not my DSL link. But that was nearly two years ago. What is it like today? I'd like to imagi...

Computation versus communication: this is a classic systems question. There are (experimental) network systems that factor in both the speed of the communication links and the local CPU. What it decides to do depends. With a fast CPU at hand you compress before sending. If it's slow you just send as...

So I was wondering if the win/draw/lose and unique/not unique move information can be stored in 2 bits. It seems that - with a little trick - it can be stored: 00 - unique move draws 01 - unique move wins 10 - lost 11 - draw or win (and there is no unique move) This is an interesting alternative th...

There's another way to optimise compression vis-a-vis the 'broken' positions. Since they are never going to be accessed, they can be set to W, D or L depending on what maximises the compression - after you have noted the correct stats. I don't think anyone has done any experiments on this. g You ma...

Or: some recent experiments in EGTB compression. Earlier this year codeman raised the idea of squeezing Nalimov's already-compact indexing scheme even further. I expressed doubt, warning not to underestimate the difficulty of said undertaking - and that compression picks up the slop anyway. So I dr...

In addition, it is satisfying to finally make good use of the 4th bit pattern. A forgot to describe a practical detail. To create these things my plan is not to configure a generator to make wldr bitbases, but to down-convert existing DTM tablebases. And then apply a second pass with a DTZ50 tableb...

In the past months I have been writing a bitbase generator. ... The code is written in a very general way, so that it would even generate n-men bitbases. The main feature of this format is the space advantage. The final file only takes 1 bit per position and during generation it takes 2 bits. Congr...

A timely subject, for as it happens I have a new bitbase format to propose. I call it a "wldr bitbase", short for win/loss/draw/rule. The idea is that both regular draws and drawn-by-the-50-move-rule draws are represented. It sprang from two sources, a) all the recent discussion about DTZ ...

Now for the computational challenges. Given an endgame 'E', what set of positions 'P' maximises the Pass Factor |DP|/|P|, and what endgame 'E' has the greatest Pass Factor? Oh yes, to your question then. While I am not a CS theoretician, this sounds like a variant of the minimal set coverage questi...

Let 'DP' be the set of positions that are currently wins for White but would be draws if all the positions in 'P' were defined as draws [in a Chess Variant called Chess(P)]. How about: let 'SC' be the set of positions that are currently draws for White but would be wins if all the positions in 'P' ...

Codeman wrote:I am working on a very general bitbase generator that works with n-men.

Since you are thinking very general, can you make the position generator work for arbitrary WxH rectangular chess boards, with and without castling and en passant?

john

step 4. Extensions to support complete 7-man tables. That will get short one day too. Why not program it to do n -men tables? I suppose it is because I don't know how to do that. At least not easily. The only solution I know of is meta-programming. The writing of one program (tbgen) with another pr...

Is your tbgen2 code public? Getting closer. My intention to release it as open source. Before releasing it I'd like to conscript a beta tester, and before conscripting a beta tester I want to shake out all problems known to me. By "it" I mean: the data, example access code, some utilities...

Martin - thank you for the upload. It's been indispensable. Would you be interested in devoting your computer to FEG for another year? For, say, 42 and 42p. It is a little-known fact that FEG can generate 7-man tablebases, except for the 6-1 variety. 4-2 is necessary prep for 5-2, and it would be re...

Updated. More precise dates are appreciated. Strohlein (1970) - ? Komissarchik, Arlazarov, Futer (1973) - ? Clarke (1977) - DTC Arlazarov, Futer (1978) - ? Thompson (1975-96) - DTC (some DTM, DTZ) van den Herik, Herschbert (1985) - DTM Nefkens (1985) - DTM Zellner (1989) - DTC Stiller (1989-95) - DT...

Does someone think that some of my .tbs files are wrong - or are you referring to some other 'Guy'. Guy I don't believe the veracity of your files was being called into question. Just the completeness of the .tbs zip files on EGTB Online needed attending to. john P.S. Your inbox should have a messa...

An updated list, adding Muller's other forms and going back in history. Again: additions are welcome; possible mistakes to be corrected. Strohlein (1970) - ? Komissarchik, Arlazarov, Futer (1973) - ? Clarke (1977) - DTC Arlazarov, Futer (1978) - ? Thompson (1975-96) - DTC van den Herik, Herschbert (...