Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Counting attacked squares: how?

Author: Antonio Dieguez

Date: 12:13:23 01/24/02

Go up one level in this thread


what is entombed? like trapped or obstructed i suposse?

also, I guess that, you didn't understand what i tried to explain at all or what
you say is very deep...

in the first case, i is not the position of the piece but all the squares it can
reach.
in the second case, please elaborate more.

>That's potential mobility, and it's not very useful since it would give the same
>mobility value to entombed pieces as it would to a piece with it's full
>potential mobility. Potential mobility can be used as an estimate for material
>piece values in the endgame when most pieces are near full mobility on an open
>board, but other than that, this isn't very useful.
>
>>
>>look at what you wrote:
>>
>>a. counting...
>>b. counting...
>>c. counting...
>>
>>most chess programmers assess mobility counting a numbers of squares, and then
>>multipling or doing an array look up?
>>
>>since when I wrote mobility from the first time i use
>>(with the only difference that they are in spanish of course :))
>>
>>mobilityBishop[]
>>mobilityRookNS[]
>>mobilityRookWE[]
>>
>>so instead of a ++ or something while looping I do, for example for bishops:
>>mobility+=mobilityBishop[i];
>>
>>of course mobilityBishop[i] is bigger when i is closer the center.
>>
>>By the way I have anothers:
>>
>>atacabilityBishop[][]
>>etc.
>>
>>and in the second entry i put also the enemy king. Very cool.
>>
>>
>>
>>>In an evaluation function, it makes sense to count
>>>and reward attacks to occupied and free squares.
>>>However, this can be done in several ways.
>>>Currently, I have the following data available
>>>and I assign bonus points for all these three
>>>count results:
>>>
>>>a. counting each square that I attack
>>>   at most once, regardless of the number of
>>>   attackers and defenders for that square.
>>>
>>>b. counting all my attacks to squares, so this
>>>   count is 2 for a square if both my knight and
>>>   my bishop (and no other pieces of mine) attack it.
>>>
>>>c. counting all squares that I control in the
>>>   sense that I attack it with a given piece
>>>   and the opponent defends it only with
>>>   more expensive pieces. For example, I regard
>>>   a square in my control if I attack it with a pawn
>>>   (and possibly other pieces as well), while the
>>>   opponent may defend it with as many
>>>   non-pawn pieces as he likes.
>>>
>>>If you have a opinion (preferably based on experience
>>>and chess knowledge) about the relative merits of
>>>these counts in an eval function, please indicate
>>>this by giving weight factors.
>>>For example:
>>>c 3, a 1, b 0 (if you regard b as useless).
>>>(I hope your answer will not be a 0, b 0, c 0 -;)
>>>
>>>Leen



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.