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Subject: Re: Free Piece/Square Tables

Author: Uri Blass

Date: 20:01:38 09/21/04

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On September 21, 2004 at 22:44:33, Robert Hyatt wrote:

>On September 21, 2004 at 21:53:47, Dann Corbit wrote:
>
>>On September 21, 2004 at 19:41:42, Stuart Cracraft wrote:
>>[snip]
>>>// white knight
>>> {
>>>  OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF,
>>>  OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF,
>>>  OFF,  64,  41,  60,  67,  67,  60,  41,  64, OFF,
>>>  OFF,  48,  79,  91,  76,  76,  91,  79,  48, OFF,
>>>  OFF,  57,  86,  95, 111, 111,  95,  86,  57, OFF,
>>>  OFF,  77, 105, 123, 129, 129, 123, 105,  77, OFF,
>>>  OFF,  99, 124, 129, 145, 145, 129, 124,  99, OFF,
>>>  OFF , 79, 114, 116, 144, 144, 116, 114,  79, OFF,
>>>  OFF,  53,  77, 108,  81,  81, 108,  77,  53, OFF,
>>>  OFF,   0,  71,  73,  73,  73,  73,  71,   0, OFF,
>>>  OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF,
>>>  OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF, OFF
>>> },
>>
>>A value of 64 for A8 and H8 seems highly suspect to me.  Similarly for A1 and H1
>>for the black knight.
>
>
>Any positive value for _any_ square on the edge of the board seems to be more
>than "a bit suspect".  They look outright _wrong_...

values are relative so I see no problem with non negative values
I have only positive values in my piece square table.

Everything that worth more than  nothing is positive for me.
I have not one value for the knight but 64 values based on the square of the
knight.

I see no reason to have special value for the knight except 64 values when 64
values already give all the picture.

If I want to evaluate black knight at c3 then
pcsq[KNIGHT][c3] give me the relevant information and if you want to evaluate
white knight at c3 then pscq[KNIGHT][flip[c3]] can give you the same
information.


>
>The problem is that it is very likely that the pc/sq values are not independent
>variables, they are closely associated with other eval terms modified during the
>tuning.  Trying to transplant them to a different program/evaluation is a
>mistake...

I agree about it.

Uri



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