CCRL Discussion Board

For 3 pieces and more it would depend on the kind of piece, right? The more powerful the piece, the more positions there are where it would check the King, and these would all be illegal with that side to move (in your definition). I never bother calculating legal positions; I always express everyth...

To Joshua: WinBoard of course supports this (just set it to variant normal and 3 ranks, 3 files). I don't know any engines that play it, though. (And I could imagine an engine could play perfectly, being able to analyze to end-of-game from a given position.) To Kirill: Now you did 3x3 Chess, can you...

Well, that interface already exists, and is called WinBoard. I use it all the time to run fairygen. It makes it like playing any other Chess program, except that it is mandatory to first set up a position with the right number and type of man. You can even use 'retract move' if you played a move tha...

That is a hard question. The problem is that a quite large fraction of all possible positions with a certain material combination is not tactically quiet. And after the tactics has been played out, you are in a different end-game, which can easily have the opposite outcome from the one you are inter...

The DTC of this end-game also has a very unusual multi-peaked distribution:



99.6% of all wtm positions is won, 66% of all btm positions lost. But 64% of all lost btm positions has a DTC of more than 50 moves.

I recently encountered a 4-men end-game that was generally won, but so close to the edge that it could take upto 75 moves to force conversion. This was for King + Rook vs King + Waffle, where Waffle is a piece (occurring in the Clobberers army of Chess with Different Armies as the Knight substitute)...

Nothing wrong with exploiting luck when it comes your way! And yes, in the case of KQKP a2 is the interesting and relevant case. I only gave it as an example to show that imperfection of the knowledge does not always back-propagate through the EGT hiearchy. And this actually happens quite often. 100...

I'm not entirely sure what you mean, but generating a correct set of 7-men tables will involve generating all subtables and all successor P-slices. I doubt many will be interested in not entirely correct knowledge, even though that will be good enough for practical play. I am not talking about &quo...

If any effort is going to be made at all, I think it would be best to go for a novel 'distance to progress' metric. Capturing a piece of the losing sides, or pushing your own pawn is progress, but (forced) sacrificing your own pieces, or allowing the opponent to advance his pawns, in general is not....

For some reason I cannot even run the 12x12 board with 4 men on my bigger machine, although it would only take 410MB. With 11x11 all corners are the same color, so of course nearly half the positions have the Bishop on the wrong color in KBNK, so that the number of lost positions drops from over 80%...

I guess fairygen could be easily adapted to do true 4x4 generation, saving a factor 4 on memory usage (and run time) per chess man. Even with 7 men it would then only use 1/4 of the memory it uses now for a 5-men, and 8-men (octo-symmetric) would only take 512MB. But of course 4x4 boards are not ver...

Well, there is zero probability that two independently chosen real numbers (or even rational numbers) would be equal. This game has a problem anyway if you assume exactly simultaneous moves by opposite sides are possible (e.g. white would play Qa1-a8 and black Qa8-a1 at the same time). So I assume t...

I have the piecedef file editted so that 5 of the piece slots will always generate the correct piece, so I can just change these specifically when needed. Itis very strange that this would be needed. But aslong as you don't show me the command you use to start up the generator it cannot be solved.....

OK, I will take a look at it. Since I implemeted WinBoard protocol I have only be using the EGTgen as WinBoard engine. This works perfectly, but does not use the octal input. (In stead it accepts the position through commands like Ke4, and the move in long algebraic format, e4e5.) So I cannot exclud...

Does anyone have experience with generating tablebases for international draughts (on 10x10 board)? It seems to me that it should be possible to build 9-men. Because exchange symmetry is typically very high (all pieces of same type), and the board is effectively smaller (50 squares in stead of 64).

It generates now without errors, but it will always generate a different endgame than specified, and will always show a different position than I entered. Hmm, that sounds bad. Let me make sure I correctly understand the problem. You are using it in stand-alone mode from the command line, right? Ca...

A screenshot:

Did you add the line #include <string.h> somewhere in the beginning, like koistinen mentions? The error message suggests that the compiler misjudges the type of strchr (which finds a character in a string), which should be defined in this header file. Onething I wondered when I saw turnless chess wa...

I released yet another version of the EGT generator (see the other thread I started). This one supports one more thing you proposed, namely the possibility to declare selected positions ('sub-goals') a win. Like having the black King in a corner (even if it is the safe corner). You can list the coll...

for(tb=p;4095&(long)tb;) ++tb; /* align with cash line */ Ah, that is probably a 64-bit issue. I will fix it in my next release. I see the output is a it verbose, because it prints what it reads from the piecedef.ini file (after expansion of omni-directionality). This originally served only for...

I released a new version of my WinBoard compatible EGT generator. (Source + Windows binary downloadable from http://hgm.nubati.net/fairygen.zip .) Like the previous version it can generate 3, 4 or 5-men EGT with arbitrary octo-symmetric pieces, and can work under rules where black can null-move (-0 ...

I have uploaded a new version of the generator (same link). It fixes a probing bug I discovered for when the King was on the diagonal, and a bug in the determination of color-binding of pieces in the piecedef.ini file (affecting the number of columns in the rep2.txt stats file). But the most importa...

Eventually I want to get around to studying these concepts for every piece type, like if Knights moved as Camels when not capturing, they would lose a lot of their straightforward cornering abilities, but would be able to maintain control of the same square when moving. I have done some measurement...

A pair of mFcW (here indicated by W), despite them having only 4 non-capture and 4 capture targets is actually a very strong force. It is a bit like a self-protecting Commoner. Look at the following mating sequence. (My counter-play by hand was not completely optimal, but close.) [Event "Comput...

OK, that would explain it. Thanks!