Author: Robert Hyatt
Date: 19:42:27 10/28/99
Go up one level in this thread
On October 28, 1999 at 05:53:47, Andrew Williams wrote:
>On October 27, 1999 at 17:08:40, Scott Gasch wrote:
>
>>[...]
>>>int simplePP[8] = { 999, 55, 33, 23, 16, 12, 0, 0 };
>>[...]
>>
>>This is interesting... a pawn on the seventh for cyclone is 255 (+2.55) while on
>>the 6th rank is 128. It also gets a passed pawn bonus of 30 unless it is
>>blocked in which case it is 15. King support is 20. Connected passed pawns get
>>+3 each additional.
>>
>>The reason that I used 255 as the 7th rank static bonus is because the engine
>>was so cavalier about playing passed pawns until I upped this drastically. A
>>good percentage of its losses were due to ignoring a passer and doing other
>>stuff until it got to the 6th or 7th rank. It was not until then that the
>>program realized it was in trouble.
>>
>>I justify the 255 score because even an unpromotable but sustainable passed on
>>the seventh is tying up at least one minor piece. This is often a winning
>>advantage for the side with the pawn threat.
>>
>>Comments?
>>Scott
>
>I've found that with very high scores for passed pawns on 6th/7th, my program
>manages to force a PP up there during the middlegame, but with most pieces
>still on the board it gets surrounded and captured, leaving my program with
>whatever positional weaknesses it had to concede to get the Pawn there in the
>first place. I prefer to rely on my other features to tell me if the Pawn
>deserves a mega-bonus or not.
>
>Passed pawn evaluation is tough. Apart from King Safety, this is the part of my
>evaluation that has had most work.
>
>Andrew
simple answer: scale the score to be proportional to the inverse of the
remaining material. less material... passer is worth more. This is how
my outside/candidate/majority scores are all handled. A majority is not
important with queens rooks and some minors on the board.
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