Computer Chess Club Archives




Subject: Re: Very easy mate to solve.

Author: leonid

Date: 12:09:45 12/24/01

Go up one level in this thread

On December 24, 2001 at 13:30:10, Heiner Marxen wrote:

>On December 24, 2001 at 06:47:47, leonid wrote:
>>On December 23, 2001 at 11:51:53, Heiner Marxen wrote:
>>>On December 23, 2001 at 08:18:16, leonid wrote:
>>>>Probably our chess solving part is very close in response, even if your initial
>>>>speed is much better. How we ever come to this closeness is a mystery for me.
>>>>Few times I tryed to find some visible explanation for this but each time I
>>>>could see later that my explanation was wrong. Fact is that our two solvers
>>>>stays completely aside from main part of mate solvers in "heavy positions".
>>>That is not so much of a mystery to me:  our two programs are the only
>>>non-trivial, brute-force, full-width mate solvers I know of.  I.e. these two
>>>programs share a certain approach/algorithm which others don't do.
>>>[Alybadix may be an exception (I just don't know)]
>>I am not that sure about this since I used special mate solver inside of Hiarcs
>>package. I presume that this specialized engin use brute force and full-width
>>search. It have nothing like selective search. Its work also give impression
>>that it make its hunt for mate in the same way like your program do. It look for
>>it at constantly growing depth. In the same time, I found no visible difference
>>between this engin branching factor for heavy positions and some other good
>>chess programs, like Genius, when those programs explicitly look for mate.
>(I do not have Hiarcs and have never used its mate solver, so I'm guessing)

I bought my Hiarcs around 2 years ago and it went with many engins inside. One
of those engins is Mate 2.0. It cold be that you will be able to find this
program on Web.

It is after seeing mate solving engin that I was puzzled why your is not there.
Your is already compatible in many ways and you can ajuste even farther if this
will be needed.

>So the Hiarcs mate solver is "brute-force" and "full-width".  I suspect it is
>not non-trivial, i.e. not many hours of programming/testing/development
>have been spent to speed it up.
>Whether this is correct or not should be possible to decide by the "basic speed"
>(time needed for say a mate in 4) and the EBF, as compared to your and my
>values.  If the basic speed of off by a factor of 10 or more... there surely
>is something to improve easily.  And if the EBF is consistently say twice as
>large, dito.

Today I looked into one position where I could see that our programs do quit
differently its inner work. In it your program went almost instantly where mine
was slow in responding.

[D]RqqkqqqR/QPqbbqPQ/rNPBBPNr/PnpQKpnP/8/8/8/8 w - -

8 moves deep mine took already 11 min and 28, when you only 8.62 seconds.
Conditions and computer are identical.


>Merry Christmas!

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