Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Chess program crash generator

Author: Uri Blass

Date: 02:20:38 05/11/05

Go up one level in this thread


On May 11, 2005 at 02:17:57, Sune Fischer wrote:

>On May 10, 2005 at 18:11:52, F. Huber wrote:
>
>>On May 10, 2005 at 17:43:15, Sune Fischer wrote:
>>
>>>On May 10, 2005 at 14:00:25, F. Huber wrote:
>>>
>>>>IMO at least 2 conditions should always be true:
>>>>1) exactly one king for each side
>>>>2) a maximum of 16 pieces for each side
>>>
>>>Number 2 is not strictly necessary, I think many engines can
>>>play perfectly sensible "chess" with more than 32 pieces.
>>
>>That depends on the engine´s implementation details - it would certainly make
>>problems, if the engine uses some kind of piece tables.
>
>Yes it will depend on the implementation but I don't think there is
>anything in the game rules as such that prohibits it, other than the
>fact that the position is illegal because you can't reach it from the
>opening position.
>
>>>However, to be well defined at least the following must be true
>>>
>>> *) no pawns on 1st and 8th rank
>>
>>Here we would have to differentiate:
>>A white pawn on 1st rank (or a black one on 8th rank) shouldn´t really be a
>>problem (at least not for the move generator) - it could simply move like any
>>other pawn, and if reaching the 2nd rank even make a double-step.
>
>If you start to define new rules a lot of things can suddenly make sense, but
>there is currently no rule that tells us how such a pawn would move.
>
>>For a white pawn on 8th rank (or black on 1st) I would have a good idea for a
>>new chess variant:
>>Whenever a pawn reaches the 1st/8th rank, it is not necessary to promote him
>>immediately - he simply waits here until he´s needed, and must/can be promoted
>>to any usual piece only when he is moved the first time!
>
>So again we would have to redefine the game. :)
>
>>Isn´t that a good idea?
>>What must I do to patent it? ;-)
>>Any hints, Ed Trice? :-)
>>
>>>>That are e.g. the necessary requirements for Chest, and seem quite logical
>>>>to me - everything else should not really confuse a well programmed engine!
>>>
>>>Hmm.. :)
>>
>>How should I understand this? Could it be that Frenzee _gets_ confused? ;-)
>
>Frenzee can handle 15 pieces of each type for each side (only one king though).
>It's just exploiting the observation that the number 9 fits in 4 bits :)
>
>There are other observations to be made and I think writing a strong engine
>requires one to take advantage of many of those observations.
>Therefore I'm not surprised that if the stronger the engine the less
>flexible the code will be.

I think that people care too much about speed differences.

The important thing is the algorithm.
I believe that it is possible to use the same algorithm and handling every
position without being more than 2 times slower and an engine that can beat
shredder9 with 2:1 time handicap is a very strong engine that can be
commercial(I believe that most of the commercial programs cannot do it).

Movei may also crash in position when the king is threated from 2 bishops
direction but I could do it 1% slower without that problem.

Unfortunately I am too lazy to change it now.

I decided that speed is not important at this moment and I could probably do
latest movei at least 10% faster without allowing the users to change parameters
of Movei personality.

If Movei will be able to beat the best commercial program with 2:1 time handicap
I may start to think about speed optimizations.

I do not think to spend time about it before doing it.

Uri



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.