Author: Don Dailey
Date: 17:47:57 08/16/98
Go up one level in this thread
On August 16, 1998 at 16:17:51, fca wrote:
>On August 16, 1998 at 10:06:53, Don Dailey wrote:
>
>>On August 15, 1998 at 22:18:24, Jeff Anderson wrote:
>>
>>>Can someone perhaps give me a rundown of the piece values used by different
>>>chess programs? How do small changes piece values in programs affect their
>>>play?
>>>Thanks,
>>>Jeff
>
>>Here are some values Larry Kaufman recommended that he felt would make
>>most decisions reasonably correct. It is based on 1/3 pawn units,
>>which he felt was the lowest unit that can return good values. He
>>also considered finer resolution like 1/4 units but thinks the 1/3
>>unit is the best if you want the unit size to be relatively grainy:
>
>>pawn 3
>>knight 3
>>bishop 10
>>rook 15
>>queen 29
>>Bish Pair 1
>
>Try 9 for knight instead, Jeff, else expect some heavy losses for your program
>:-))
Try 10 instead, that is what I meant. Of course that makes the following
discussion moot, sorry about the typo!
- Don
>Read all of what I state with the caveat that of course values cannot be
>ascribed to pieces in general terms, it depends on the whole position, so we are
>only talking crude averages over {whole game} etc.
>
>An interesting effect of the above is assuming both sides had a bishop pair to
>start off with, the "close exchange" of B + N v R + P would cost
>
>10 + 9 + 1 (loss of B-pair) v 15 + 3
>
>i.e. 20 v 18
>
>i.e. 2/3 of a pawn down for the loser of B+N. I think this is wrong, and should
>be 1/3 pawn. If we up R to 16 it also produces a more reasonable result v Q, as
> (ignoring 2 rooks in case there is a 2-R bonus)
>
>R + B + P v Q
>
>with my amendment gives
>
>16 + 10 + 3 v 29
>
>i.e. 29 v 29
>
>i.e. fits in with my OTB observation that R+B+P v Q often holds...
>
>
>Kind regards
>
>fca
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