Computer Chess Club Archives




Subject: Re: MTD(f)

Author: Uri Blass

Date: 03:54:37 01/15/04

Go up one level in this thread

On January 15, 2004 at 06:26:47, Tord Romstad wrote:

>On January 14, 2004 at 20:11:53, Dann Corbit wrote:
>>On January 14, 2004 at 16:49:29, Tord Romstad wrote:
>>>Another simple trick is to reduce the resolution of your evaluation
>>>function.  In my pre-MTD(f) days, I used pawn=128.  I still use pawn=128
>>>as the internal unit in my evaluation function, but before returning
>>>the final score I divide the score by 2.  This simple change made my
>>>search noticably more efficient.
>>Did you try other divisors besides 2?
>No, not yet.  When I have cleaned up my source code a bit, I plan to make
>it possible to choose the divisor in my init file.  I don't think bigger
>divisors would result in stronger play, though.  It would make the engine
>faster, but I am afraid a lower resolution would hurt the already poor
>positional knowledge of Gothmog.

I do not know why do you think that it's positional knowledge is poor.

I guess that with half of the poor positional knowledge of Gothmog movei can
become 50 elo better.

I am interested in what bonus you give for passed pawns that can safely advance
and if you use the side to move to decide about the bonus.

After implementing SEE similiar to Crafty one of the next steps may be to use it
for the evaluation.

Calculating one SEE per node make me less than 10% slower so I guess that it can
be clearly productive.


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