Search found 223 matches

by h.g.muller
Wed Mar 27, 2024 8:43 am
Forum: Endgame Tablebases
Topic: Chess engines can soon simulate tablebases for any number of pieces?
Replies: 2
Views: 30434

Re: Chess engines can soon simulate tablebases for any number of pieces?

Determining the W/D/L of a given position with a 99.9% probability to be correct is not 'simulating a tablebase'. Or with 99.999% probability. For one, an EGT will offer 100% correctness, and thus has an infinitely smaller probability to be wrong. But the most important distinction is of course that...
by h.g.muller
Wed Mar 27, 2024 8:01 am
Forum: Endgame Tablebases
Topic: Duck Chess
Replies: 3
Views: 10631

Re: Duck Chess

I think I got it working. I had a bit of trouble extracting the best move from the EGT in the proposed format. In particular the Duck part. Normally for an EGT that contains both wtm and btm positions you just do a 1-ply search from the current position, to select the target with the best DTM. But f...
by h.g.muller
Fri Mar 15, 2024 4:56 pm
Forum: Endgame Tablebases
Topic: Duck Chess
Replies: 3
Views: 10631

Re: Duck Chess

I was distracted from this project for a long time. But it seems too interesting to abandon it entirely. In particular it would be fun to make a web applet where you could play the KRK end-game in Duck Chess. Since this is ony a 3-men EGT, efficiency is not really an issue. For propagating the DTx I...
by h.g.muller
Fri Mar 15, 2024 12:53 pm
Forum: Endgame Tablebases
Topic: Converting FairyGen to other Programming Languages
Replies: 1
Views: 27900

Re: Converting FairyGen to other Programming Languages

And, does it run properly? You might be interest in the checkmating applets I wrote in JavaScript for 2-vs-1 and 3-vs-1 checkmating: https://www.chessvariants.com/page/MScheckmating-applet There also is a version that can handle bent sliders and hoppers: https://www.chessvariants.com/membergraphics/...
by h.g.muller
Sat Jan 21, 2023 11:05 am
Forum: Endgame Tablebases
Topic: Duck Chess
Replies: 3
Views: 10631

Duck Chess

I am thinking about generating EGT for Duck Chess . The Duck can of course be treated like an extra piece. This would lead to an extremely large branching ratio, as both the Duck and another piece must be moved independently in each turn, and the Duck can be moved anywhere. It also drives up the mem...
by h.g.muller
Thu Oct 06, 2022 12:07 pm
Forum: Endgame Tablebases
Topic: How hard would it be to implement Tetris pieces into chess endgame tablebases?
Replies: 6
Views: 12891

Re: How hard would it be to implement Tetris pieces into chess endgame tablebases?

In the abstraction in which an EGT is defined, all that exists is a set of game states that can be enumerated by an index, and transformations between those states (the move rules) for each of the two players. And two sub-sets of the game states where one or the other player has won. The latter can ...
by h.g.muller
Tue May 17, 2022 4:40 pm
Forum: Endgame Tablebases
Topic: Shatranj tablebases
Replies: 6
Views: 21988

Re: Shatranj tablebases

Again sorry for the late response. This forum has so little trafic that I look at it perhaps only twice a year. For urgent questions I can be reached at talkchess.com, which I visit nearly every day. I never save the EGT I generate; I generate them only to get the WDL statistics. I might not even ha...
by h.g.muller
Mon May 13, 2019 2:41 pm
Forum: Endgame Tablebases
Topic: Identifying fortress draws
Replies: 1
Views: 40167

Identifying fortress draws

I added an easy trick to my EGT generator for getting a better impression of how many fortress draws a given end-game contains. Normally this would be masked in the statistics by the much larger number of draws due to grabbing an unprotected opponent piece (usually on the first move), changing the m...
by h.g.muller
Tue Oct 02, 2018 9:20 am
Forum: Endgame Tablebases
Topic: EGT-driven practice applet for 3-men checkmating
Replies: 0
Views: 33746

EGT-driven practice applet for 3-men checkmating

I set up a web applet where one can practice checkmating with various pieces, including custom designed pieces, by playing against a (3-men) EGT. See http://hgm.nubati.net/rules/EGT.html . The applet is powered by JavaScript, and generates the required EGT on the client machine. I had expected this ...
by h.g.muller
Wed Jun 15, 2016 9:01 pm
Forum: Endgame Tablebases
Topic: Xiangqi EGT
Replies: 0
Views: 35184

Xiangqi EGT

I have started building End-Game Tables for Xiangqi (Chinese Chess), to enhance my engine for the upcoming computer Olympiad. It turns out that Xiangqi exngines tend to require a lot of technical skill. Quite unlike Chess, where end-games with a significant material advantage tend to 'win themselves...
by h.g.muller
Wed Mar 09, 2016 12:06 pm
Forum: Endgame Tablebases
Topic: Interesting triangulation
Replies: 0
Views: 36347

Interesting triangulation

In the Makruk end-game King + Silver General (S) + Ferz (M) vs King I encuntered the following manoeuvre to triangulate. It seems of general interest, as this is a case where really everything seems to be most unfavorable: neither Silver nor Ferz can triangulate, and the Silver breaks diagonal symme...
by h.g.muller
Sat Feb 20, 2016 6:25 pm
Forum: Endgame Tablebases
Topic: Mate with Bishop and Generalized Leaper
Replies: 1
Views: 38366

Re: Mate with Bishop and Generalized Leaper

Interesting. It seems your intuition that larger boards are better is right, at least considering the Flamingo (F'). On 8x8 and 10x10 boards KBF'.K is a general draw, but on 12x12 it is a general win: $ ./4men allocate 432988480 bytes at 6fa040 mated mate King captures 66718336 mates 1800 ( 2.84 sec...
by h.g.muller
Thu Feb 12, 2015 5:06 pm
Forum: Endgame Tablebases
Topic: KBNK
Replies: 3
Views: 44727

Re: KBNK

This chess on infinite edgeless boards is really something... It seems an active topic of math research, raising some very deep problems. In the mean time I found this thread about KBNK: http://chess.stackexchange.com/questions/1432/kbn-vs-k-checkmate-on-nonstandard-boards It contains an optimal mat...
by h.g.muller
Thu Dec 18, 2014 7:09 pm
Forum: Endgame Tablebases
Topic: CCRL Games on Scid
Replies: 2
Views: 44737

Re: CCRL Games on Scid

I understood that due to abuse of the PGN Round tag the CCRL database is not compatible with SCID. If you have access to a Linux system or Cygwin you could use 'sed' to delete all Round tags.
by h.g.muller
Wed Nov 19, 2014 6:23 pm
Forum: Endgame Tablebases
Topic: KBNK
Replies: 3
Views: 44727

KBNK

I was wondering, is KBNK a won end-game on any (even) size board, and perhaps even on an infinite board? There doesn't seem to be a faster-than-linear increase in the length of the longest mate, as one usually sees in end-games that at some point cease to be won (e.g. K+K vs K). For KBNK I find 6x6:...
by h.g.muller
Mon Oct 20, 2014 5:42 pm
Forum: Endgame Tablebases
Topic: The wonderful end-games of Team-Mate Chess
Replies: 3
Views: 42749

Re: The wonderful end-games of Team-Mate Chess

The funny thing is that 'any size board' is not the same as 'infinite board (with 1 corner)'. I am not sure what exactly the extra condition is that you would have to impose on the piece constellation on an infinite board to make it equivalent to 'any size'. I would expect something like "when ...
by h.g.muller
Tue Oct 14, 2014 10:06 am
Forum: Endgame Tablebases
Topic: The wonderful end-games of Team-Mate Chess
Replies: 3
Views: 42749

The wonderful end-games of Team-Mate Chess

I created a novel Chess variant, which distinguishes itself by the peculiarity that no single piece occurring in it has mating potential. So Checkmates will also have to be performed by pairs of pieces. Hence the name 'Team-Mate Chess'. For people that like KBNK this would be the ultimate Chess vari...
by h.g.muller
Thu Apr 03, 2014 9:30 am
Forum: Endgame Tablebases
Topic: Some DTM50 work.
Replies: 23
Views: 177822

Re: Some DTM50 work.

My argument would be that in the end, to do the biggest thing that can be done, you would need that code complexity anyway. And once you have it, you might as well use it for the cases that did not really need it, rather than writing specialized code for that. I don't see why slicing would slow thin...
by h.g.muller
Wed Apr 02, 2014 9:31 pm
Forum: Endgame Tablebases
Topic: Some DTM50 work.
Replies: 23
Views: 177822

Re: Some DTM50 work.

I would always slice by square. Why not use the extra reduction if you can?
by h.g.muller
Wed Apr 02, 2014 5:33 pm
Forum: Endgame Tablebases
Topic: Some DTM50 work.
Replies: 23
Views: 177822

Re: Some DTM50 work.

Maybe the solution to this problem is to write down the results of each iteration on disk, and to keep on RAM only the information needed for next iterations. Indeed, this seems the way to go. If the working set consists of 2 bytes per board position (one byte for each side to move), the bytes coul...
by h.g.muller
Wed Apr 02, 2014 4:57 pm
Forum: Endgame Tablebases
Topic: DTM50 5-men tablebases : generation has started
Replies: 18
Views: 101963

Re: DTM50 5-men tablebases : generation has started

OK, I'll join the discussion in that thread, then. But please note I have added something to my previous post, which probably crossed yours (as you don't quote it).
by h.g.muller
Wed Apr 02, 2014 11:26 am
Forum: Endgame Tablebases
Topic: DTM50 5-men tablebases : generation has started
Replies: 18
Views: 101963

Re: DTM50 5-men tablebases : generation has started

So do I understand correctly that you treat every (position, plycount) combination as a separate element of the EGT, multiplying its size by 100? What I had in mind was to let the EGT (or at least the working space for generating it) only contain one element per position, but keep both the DTZ and t...
by h.g.muller
Wed Apr 02, 2014 9:28 am
Forum: Endgame Tablebases
Topic: Newbie question about building single 6-men
Replies: 1
Views: 28658

Re: Newbie question about building single 6-men

I see no one has reacted to your posting for months. I can't help you with the Nalimovs; I never used those. You raise an interesting point about end-game tables: the information they contain is not very helpful to humans. There is little logic in the shortest lines of play they imply, and if there ...
by h.g.muller
Wed Apr 02, 2014 8:44 am
Forum: Endgame Tablebases
Topic: DTM50 5-men tablebases : generation has started
Replies: 18
Views: 101963

Re: DTM50 5-men tablebases : generation has started

What algorithm is used to generate DTM50? Is it sufficient to start from DTM50 successors, and start generating like you would for DTZ, except that you propagate DTM together with DTZ? And then, when a retro-move reaches a position that already was a DTZ win/loss (so you would normally ignore it), o...
by h.g.muller
Sun Jun 24, 2012 8:09 pm
Forum: Endgame Tablebases
Topic: Number of positions in chess endgames
Replies: 20
Views: 145692

Re: Number of positions in chess endgames

I always make the effort to count symmetry-reduced positions twice when I take the statistics. This because I am interested in answering the question: "when you set up a random position, how large is the probability it is won (lost)?". When two different positions are symmetry equivalent, ...