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Subject: Re: Fine tuning the engine's strength

Author: John Coffey

Date: 07:43:35 07/25/00

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On July 24, 2000 at 21:39:42, blass uri wrote:

>On July 24, 2000 at 19:34:02, John Coffey wrote:
>
>>On July 24, 2000 at 14:45:01, KarinsDad wrote:
>>
>>>On July 24, 2000 at 14:23:19, KarinsDad wrote:
>>>
>>>>On July 24, 2000 at 13:30:06, Jari Huikari wrote:
>>>>
>>>>>On July 24, 2000 at 13:01:36, John Coffey wrote:
>>>>>
>>>>>>Only slightly related to the GUI is having a range of abilities from beginner
>>>>>>up to the top level that can be fine tuned.
>>>>>
>>>>>>I tried it on Chessmaster 6000, all the levels 1600 and below were dropping
>>>>>>pieces, and the next level up was smashing me at speed chess (my quick rating
>>>>>>is 1978.)
>>>>>
>>>>>I have thought about how this could be done. One idea that came into my
>>>>>mind was simply to put some delay routine into search to make it slower
>>>>>and thus playing weaker.
>>>>>
>>>>>					Jari
>>>>
>>>>
>>>>I do not think those types of solutions work, i.e. less time, fewer nodes, lower
>>>>depth, etc. The program will still play relatively strong until some other
>>>>algorithm takes over (i.e. the below 1600 drop piece problem that John noted).
>>>>
>>>>What you need is a chess engine that generates multiple ply 1 PVs. Then, it
>>>>could randomly pick a different PV each move.
>>>>
>>>>So, for example, if it had 5 PVs that it could choose from, at 2600 setting it
>>>>would always pick PV 1 each time. At 2400 setting, it would occasionally pick
>>>>the PV 2 move. At 2200, it would pick PV 1 45%, PV 2 45%, PV 3 10%. At 1600, it
>>>>might pick PV 1 20%, PV 2 20%, PV 3 20%, PV 4 20%, PV 5 20%.
>>>>
>>>>Then, the computer would not be dropping pieces, even at a 1000 setting (even
>>>>though 1000 players often do drop a piece). But, it would rarely be playing the
>>>>best move in those positions at the lower settings.
>>>>
>>>>Of course, you would have to add in some logic that the scores of the PVs could
>>>>not be that drastically different. For example, NxB would normally result in PxN
>>>>as PV 1. If PV 2 did not have a similar PV score to PV 1 (i.e. there were no
>>>>waiting moves that do not lose the bishop), then the program would still make
>>>>the PV 1 move, regardless of setting.
>>>>
>>>>KarinsDad :)
>>>
>>>I forgot to mention that lowering the depth in conjunction with this type of
>>>solution would be optimal. It doesn't make sense to pick a PV 5 move that avoids
>>>a capture 14 ply down that is also avoided by PV 1 through 4. If the setting is
>>>1200 rating, then the program should not generally be seeing more than 4 to 6
>>>ply down before deciding on it's PVs.
>>>
>>>KarinsDad :)
>>
>>Interesting but ....
>>
>>Computer's today
>>run at hundreds of mhz.  It wasn't always so.  When I played computers
>>that ran at 3 and 4 mhz, it was possible to select levels from very weak
>>up to the top level (which might have been 2000.)  But today's comptuers usually
>>have a minimum setting of one second per move.  Fritz at that time setting is
>>probably
>>still a master at speed chess.  I have tried to set programs at fractions of
>>seconds per move, but they won't allow it.  :-)
>
>You can set level of x plies per move.
>1 ply per move is the same level in all computers and is relatively weak level.
>
>Uri


Although I agree, I think it is a poor solution.  At 5 or 6 ply the computers
will play a very strong middle game (especially at speed ches) but a very weak
endgame.

why is the only way to limit how much a computer thinks done in ply?  Why must
1 second a move always be the minimum?  What is wrong with the idea of being
able to control the number of nodes a computer looks at?   (Not to give  you
a hard but, but I am wondering why such a simple solution hasn't been
implemented before.)

John Coffey



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