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Subject: Re: What is your margin between eval and material?

Author: Pham Hong Nguyen

Date: 22:34:00 10/28/02

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On October 29, 2002 at 00:34:41, Uri Blass wrote:

>On October 28, 2002 at 20:28:43, Pham Hong Nguyen wrote:
>
>>Hi all,
>>
>>I read that someone suggests the margin between the evaluations and materials
>>should not excess 1.5 of pawn. However, my margin is 1.5 of ... queen and I
>>think that causes many problems for my program: difficult to apply razoring,
>>lazy eval, cut off in qsearch...
>>
>>So my questions here are:
>>- What is the margin of Crafty?
>>- Could you share some experiences about your margin and its
>>advances/disadvances?
>>
>>Many thanks for any answers.
>
>My margin is not defined because I did not define my values for material.
>It is possible to do a linear regression in order to guess the evaluation based
>on material but I did not do it.
>
>Pieces gwt different value on different squares that and I have not one value
>for the pieces.
>6 pawns in the 7th rank are usually  evaluated as better than 8 pawns.
>
>If people tell you that the difference between evaluation and material should
>not excess 1.5 pawns then they tell you that you cannot give the right score for
>pawns in the 7th.
>It also means that you cannot evaluate unstoppable passed pawn in pawn endgames.
>
>Uri

Uri, I understand your way to evaluate because my margin is also much larger
than 1.5 pawns.

Just want to get some experiences about use of materials in some functions with
which I have problems. For example, I cannot use the values of 1.5-2 pawns for
razoring based on materials like many programs, I have to use value of rook, it
turns out I gain very little.

Do you do any thing based on materials? such as lazy eval, razoring,...?




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