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Subject: Re: Free Piece/Square Tables

Author: Uri Blass

Date: 21:06:24 09/21/04

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On September 21, 2004 at 23:04:22, Robert Hyatt wrote:

>On September 21, 2004 at 23:01:38, Uri Blass wrote:
>
>>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.
>>
>A knight on two of the corner squares is worth 0.  On the other two 64.  That
>doesn't make any sense to me...

I did not claim that his numbers are good but only that non negative numbers do
not have to be bad.

Uri
>
>
>>
>>>
>>>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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