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Subject: Re: Fine tuning the engine's strength

Author: blass uri

Date: 02:26:58 07/25/00

Go up one level in this thread


On July 25, 2000 at 01:26:15, KarinsDad wrote:

>On July 24, 2000 at 20:26:27, 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 :)
>>
>>
>>The idea has occured to me before.  Write a program that would decide randomly
>>between between the best N # of moves where N is based upon the level of
>>difficulty.  I saw the same problem that you saw which was that sometimes
>>the best move is forced.  So then you have to decide how much of an error you
>>will allow.  If you will allow a 3 point error at 1300 but only a 2 point
>>error at 1400 then you have the problem that 1300 will drop knights and 1400
>>won't.  Maybe that isn't a problem.  But maybe there would be too much
>>difference between 1300 and 1400.
>>
>>John Coffey
>
>I think the issue is one of having a program attempt to decide the average
>"power" of a move based on the setting desired. Once that is decided (does that
>mean only searching 8 ply, does that mean randomly picking between the perceived
>best three moves, etc.), the program can still play reasonably well, but it can
>also blunder if a piece hangs in 6 ply, etc.
>
>The problem comes in when the program makes a move that is SO stupid that not
>even a low rated player would make that move (in standard time controls, in
>blitz, almost everyone but extremely good players blunder). When this happens,
>the program is considered a dumb machine.

Even high rated players do sometimes blunders of not seeing one move.
It does not happen often but it happens.

I remember that it happened even to one of the world champions.

Uri



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