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Subject: Re: Detecting backward pawns

Author: James Robertson

Date: 07:43:01 06/17/99

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On June 17, 1999 at 10:10:43, KarinsDad wrote:

>On June 17, 1999 at 00:16:56, James Robertson wrote:
>
>>On June 17, 1999 at 00:10:11, James Robertson wrote:
>>
>>>I am trying to find the most efficient way to detect backward pawns, either with
>>>bitboards or the more conventional piece array. Any help is greatly
>>>appreciated!!
>>>
>>>James
>>
>>I suppose I could add to this. I decided that a backward pawn must be:
>>
>>On an open file,
>>Unable to be defended by another pawn,
>>unable to advance without capture by an enemy pawn (it may be able to advance,
>>but that wouldn't take it off the open file or defend it with another pawn).
>>
>>I cannot figure how to make this all work without tons of arrays and all sorts
>>of other nasty stuff.
>>
>>Help!
>>James
>
>Recommendation #1: Calculate square control for each square. This will also help
>you in other portions of your evaluation such as king safety.

I might, although this will be expensive....

>
>Recommendation #2: With square control, you do not need to calculate whether
>there is a protecting pawn on the adjacent file. Either the one (or two) squares
>in front of the pawn you are checking are controlled by white or by black.
>
>Recommendation #3: Set up a pawn structure hash table. Since pawns rarely move
>in the game (and in the search <40% on average), it is probably better to
>calculate pawn advantages and deficiencies once per given pawn structure as
>opposed to calculating it every time in your evaluation.

I already have pawn hashing, but it just seems creepy to have so many arrays to
find out one simple little thing like backward pawns.

James

>
>Hope this helps,
>
>KarinsDad :)-



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