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Subject: Re: Movei-Junior - the saga continues

Author: José Carlos

Date: 17:33:25 12/02/04

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On December 02, 2004 at 15:56:30, Uri Blass wrote:

>On December 02, 2004 at 14:51:04, José Carlos wrote:
>
>>
>>>What is the definition of closed files?
>>>By movei's definition closed files are files that are not open and
>>>open files are files when there is no friendly pawn that prevent the rook to
>>>go forward(there may be pieces or pawns of the opponent that prevent it to go
>>>forward but if you remove all pieces except friendly pawns the rook can go to
>>>the 8th rank).
>>>
>>>By movei's definition the b file is an open file because there are no friendly
>>>pawns in that file.
>>>
>>>Movei has a bonus of 0.1 pawns for rook on open file and panelty of 0.1 for
>>>closed file and I am not sure if that bonus and panelty is productive.
>>>
>>>It was productive in the positions that I tested at the time that I implemented
>>>it but I did not play enough games and it is possible that the positions were
>>>misleading and in different positions I could get different results.
>>>
>>>Uri
>>
>>  If there is an enemy pawn in an open line, and it's defended by another pawn,
>>that's not likely to be a useful place for a rook.
>
>I agree and I also thought about it.
>I may tell it not to give bonus for open file only when there is no protected
>enemy pawn in the same file.
>
>>  The definition to open line is a line without any pawn.
>>  A closed line is a line with a friendly pawn.
>>  A semi-open line is a line with no friendly pawn but opponent's pawn.
>>  Those three should have IMO different bonus/malus.
>
>I thought that sometimes is it better to attack opponent weak pawn and not to
>attack nothing so I decided to give semi close file and open file the same
>bonus.


  Yes, this is true in many cases. However, if a rook can enter enemy's
position, it'll probably attack weak pawns too.


>>  It is also important to check if a rook in a line can eventually move into
>>enemy's position.
>
>Movei today does not check in it's mobility evaluation if a move is to square
>that is controlled by the enemy bishops and I will probably improve other things
>before trying it.


  I don't do it in Averno either, because it's expensive. I do it when I play
chess myself though, and it's really important. In my other program Anubis,
where I have attack bitmaps in every internal node, this is almost free to
check, and I have seen it has a clear positive effect in playing strength.


>checking if an enemy pawn in the same file is protected by a pawn is more easy
>to do and I may do it.


  Yes, that's what I do in Averno.


>Uri


  José C.



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