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Subject: Re:i Want To Know More About Dedicated Chess computers..

Author: Thomas McBurney

Date: 07:25:58 04/23/04

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>
>i did not notice that!
>i just tried this out and you are right!
>:))
>
>can i ask you ,what made you try this out??
> to see if it would make illegal moves,or did you just press the play button by
>accident after the game and you noticed this??
>great observation!

I guess the thing that caught my attention was the way the computer missed
checkmate moves.  In one example, the computer only had a choice of about 30
possible moves and one of those moves lead to checkmate.  It only requires a 1
ply search (+ qsearch) to find the checkmate move.  After it thought about its
move for about 10 seconds it made a move that wasn't the checkmate move.  So I
thought there was something odd with the way it performs its search.  I think
you hit on it below, it doesn't appear to perform a iterative deepening search.
It must perform a 2 or 3 ply search without searching at the lower depths first,
then it simply runs out of time before it has finished searching all the
possible legal moves. I thought that because of the way it did its search I
thought that it might behave funny in a stalemate position (notice no stalemate
LEDs) or checkmate position.  And to my surprise after fiddling with it, I was
able to play a move and remove the king off the board and continue playing.

The Hanimex Computachess II also does not appear to use interative deepening.
Unlike the Fidelity, it will continue to think until it has considered all
moves.  That probably explains why the levels are strange with this unit.  On
level 3 it takes an average of 15 seconds to make a move, then one level up,
level 4, it takes an average of 3 minutes to make a move!  Quite a jump from
level 3 to level 4!  Also, another interesting thing with the Hanimex is in its
instruction manual it has a little note that says "On those very rare occasions
when you are easily winning but accidentally make a move that Stalemates the
computer, it will show its surprise by indicating an illegal or impossible
move".  I think this is actually a bug which they are pretending is a feature.
When you are working with a psuedo legal move generator dectecting the
difference between Stalemate and Checkmate is a little bit tricky, then throw in
non iterative deepening search algorithm then I can see a potential for a silly
bug to creep in.  Well, thats my guess anyway! :)


>probably just the way the program allocates time
>it probably spent alot of time on the earlier moves and had little allocated
>time left..so it made a move with a small 1 or 2 ply look ahead..resulting in
>diaster
>i would call this a nice "chess ego building feature "
>:))
>
>BTW... Fidelity released 3 plug-in modules for the Mini
>if you open up the back of the unit you will see an empty slot for the modules
>one of the modules was the CAC(Advanced chess module) which increased the number
>of levels to 8 and made the program slightly stronger
>
>keep an eye out for these modules on Ebay
>every now and again one of them pops up

Yes, I noticed that, it has a sticker that says "use Z8 series plug in module
only".  I will have to keep an eye out on ebay for one!  BTW, do you have the
manual for this unit?  I don't, but I would like to know what specs are for the
external power supply because I would like to buy one for it so I don't have to
use batteries.

Cheers,
Tom.



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