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Subject: Re: Mobility

Author: Pallav Nawani

Date: 16:15:58 01/06/05

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On January 06, 2005 at 18:18:40, David B Weller wrote:

>Hi Geoff,
>
>The fact that you stumble over my code is probably a credit to your
>intellegence, and if I tried to explain: attack_mask[][], I would embarass
>myself.
>
>In fact, while thinking over how to best answer your question, I too became
>somewhat puzzled as to how what I did, actually improves GES performance. It
>really is inacurate.
>
>The part I added is at the end of control.cpp and 1 line in evaluate.cpp :
>
>s += count_ctrl() * 3;
>
> the '3' is pulled from memory - I think Prof Hyatt used it for Bishop mobility,
>but since what I am counting isnt the same, it is probably way off. WAY off.
>
>The basic idea of count_ctrl() is to detirmine who 'owns' each of the 64
>squares. But it is very simple and naive. It makes assumptions which are
>probably true more often than not, but still wrong much of the time. eg., if
>white has a pawn attacking a square, but black doesnt have a pawn attacking that
>square - white owns the square. regardless of what else is attacking it. If both
>have pawns attacking [or, niether do] then the same idea is applied for knights.
>Then Bishops, then Rooks, then Queens.

So what you are evaluating is board control. I had no idea it was that useful.
Maybe I will try implementing that (after I have implemented attack tables, that
is).

Pallav



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