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Subject: Re: I don't use illegal moves EVER

Author: leonid

Date: 06:18:28 11/29/99

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On November 29, 1999 at 08:28:07, Heiner Marxen wrote:

>>And what exactly signify "adding special code for 2-mate candidates"?
>
>A "2-mate candidate" is a move of the attacker, which shall start a mate in 2.
>I.e. followed by any defender move there shall shall then follow a mate move.
>I have special code estimating the escapes around the defender king, which
>remain after a 2-mate candidate, followed by one of the defender moves,
>followed by any possibly legal further attacker move.  And if there are still
>escapes for the defender king guaranteed to be left, there is no mate in 2.
>Bingo!


Very curious way to do the logic. It is so different from mine that I can hardly
understand the basic idea. For a long time wanted to know if everybody end
somewhere on the same place when writing the same kind of logic. Until now could
see this somehow for "positional logic" but never for "mate solver".


>The success rate of this special code rarely is below 50%, typically is
>a bit above 80%, and sometimes 95%.  Overall it pays off fine.
>
>>How many moves (or plys) the mate solver looks?
>
>I'm not sure I understand your question.  When you ask for a mate in N, it
>will look 2N-1 plies deep.  N currently is limited to 30, but that can be
>changed easily.

Asked this because for only practical reason, when "mate solver" is the part of
the chess game, the most solicited mate is around 3 and 5. For solving the mate
for amateur of this kind of problems it is very open question. Often it have not
that much sense beyond 18 plys. Reason for this - verification by brute force
the smallest number of moves that lead to this mate. It can take too much time
even on the best computers when position contain many pieces. I stopped at 13
moves.


>>How big, as code, it is?
>
>150 KB code.

Very small and impressive if it is done on C or other not Assembler language.
Just as small as it must to be.


>>And what kind of variations of mate solutions are included now in the logic
>>for solving the mate, or composition of problems?
>
>mate, stalemate, selfmate, selfstalemate, helpmate and helpstalemate.


What I wanted to know is how many variation of "mate solving logic" you have in
your game. Number of variation can go endlessly. I left, for instance, only four
in my logic. Difference in version of the logic consist in the fact that each
will find at different speed solution. Some logic will find more rapidly the
response but will find the mate not all the time when it is there.

Leonid.


>Heiner Marxen   heiner@drb.insel.de     http://www.drb.insel.de/~heiner/



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