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

Author: Uri Blass

Date: 22:41:55 10/28/02

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On October 29, 2002 at 01:34:00, Pham Hong Nguyen wrote:

>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,...?

No

I have incremental evaluation so I do not need to do things based on materials.

Uri



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