Author: John Coffey
Date: 10:51:26 01/14/99
Go up one level in this thread
On January 13, 1999 at 18:07:52, KarinsDad wrote:
>On January 13, 1999 at 17:48:18, John Coffey wrote:
>
>>
>>The trouble with control of squares is that you have to take into account
>>the values of the pieces that attack a square. i.e. a pawn could control
>>a square. I had figured out that I could use bits for each type of piece
>>that attacked a square, where pawns use high bits and kings use low bits.
>>Add the bits for each side and the side with the highest number (more or less)
>>controls the square.
>
>Thanks John,
>
>I was toying with doing something in the back of my head about control of
>squares, but it was low priority. I had gotten as far as determining that the
>side with the least valuable resources controlling the square was in fact
>actually controlling it, but didn't have the time to really think about it.
>
>This saves me a lot of thought.
>
>KarinsDad :)
I believe that determining who controls what squares - especially if weights
are given for controlling squares around the enemy king, could be a useful
addition to the evalution function.
Now this issue for me is how to determine which pieces attack a particular
square. There are two choices....
1. Derive this from bitboards. Even with the advantages of bitboards this
seems to me to involve a great many steps.
or
2. My plan all along has been to update the information each time a piece
moves only on the squares affected. My evaluation of control of squares
would be incrementally evaluated as the tree is traversed. This could be slow,
but it has some advantages since a by-product of this method is that I would
have a current move list and information about captures etc, mobility etc. This
is likely to help with move ordering.
I am posting this because I would like to get the opinion of others on this
method, especially Dr. Hyatt.
john coffey
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