Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Positional scores in Eval()

Author: Tony Werten

Date: 03:58:26 04/10/01

Go up one level in this thread


On April 09, 2001 at 22:25:14, Robert Hyatt wrote:

>On April 09, 2001 at 21:17:59, Normand M. Blais wrote:
>
>>On April 09, 2001 at 18:20:07, Robert Hyatt wrote:
>>
>>>On April 09, 2001 at 16:49:21, Normand M. Blais wrote:
>>>
>>>>On April 09, 2001 at 16:21:56, Andrei Fortuna wrote:
>>>>
>>>>
>>>>>positional score > 2 PAWN_VALUE. And that will hurt my quiescence and my
>>>>>futility pruning if I assume that 2*PAWN_VALUE is max positional score. It all
>>>>>boils down to the magnitude of the positional scores versus pawn value, I think
>>>>>I have to choose either to keep big bonuses and turn futility off (or set a
>>>>>bigger margin for futility but in that case it would make futility more
>>>>>inefficient) or keep small bonuses and enjoy the reductions I get from futility
>>>>>and quiescence.
>>>>
>>>>What if you multiply the value of the material by 10 (i.e. pawn = 1000 Knight =
>>>>3000 Bishop = 3000 Rook = 5000 Queen = 10000 ) and keep the positional score as
>>>>it is.
>>>>
>>>>N.M.B.
>>>
>>>
>>>Then you become _very_ materialistic.  You will grab pawns whenever
>>>possible, even if it wrecks your king position.  You will grab a pawn but
>>>leave your opponent with an outside passer that wins.  Etc...
>>
>>I understand that the positional score is related to the material score (the
>>pawn or tempi being the unit of measurement). I made a mistake by suggesting
>>that the material value can be magnified without adjusting both the positional
>>bonuses and penalties. But would it be a good idea to have one more digit to
>>work with? A value of 1000, for instance, could represent 100.0.  And scores
>>like 112.4 and 112.8 could be set apart? Not a sophisticated idea but anyhow.
>>
>>Regards,
>>
>>N.M.B.
>
>I don't personally think the idea of "millipawns" makes a lot of sense.  That
>is _very_ fine resolution.  I used it in Cray Blitz, and in early versions of
>Crafty, but it adds to the hash entry size for one thing...

XiniX is using it. Not because it makes any sence but I like the idea that I can
give small bonusses for some stupid positional thing that I like, without
messing up the eval and still having the idea that if two positions score almost
the same, it will prefer the one I like.

Gives me a sort of personal tough feeling. ( As I said, it's not because it
makes any sence )

cheers,

Tony




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.