Author: Dann Corbit
Date: 17:11:53 09/06/02
Go up one level in this thread
On September 06, 2002 at 19:16:56, Tony Werten wrote:
>On September 06, 2002 at 17:45:15, Uri Blass wrote:
>>On September 06, 2002 at 15:46:53, Tony Werten wrote:
>>>On September 06, 2002 at 14:45:11, Dann Corbit wrote:
>>>
>>>>Did anyone notice his cutoff idea in the evaluation function?
>>>>
>>>>It seems to me to be a very good idea, and I don't know if others have tried it
>>>>out.
>>>>
>>>>Basically, it consists of three modes with two early exits...
>>>>
>>>>1. If the material + structure score alone is dominant enough, it exits right
>>>>away.
>>>>2. Otherwise, it processes the piece list. If that score is dominant, it exits.
>>>>3. Otherwise, it does a full board control scan for all 64 squares.
>>>>
>>>>It is described starting on page 62 under the section "3.3.2 Multi Staged
>>>>Design"
>>>>He gets roughly 71% evals returning in stage #1, 13% in stage #2 and 7% in stage
>>>>#3.
>>>>
>>>>It seems like it might be a big win to do it that way.
>>>
>>>It's called lazy eval and is not a good idea. The times it is wrong happen to be
>>>the important ones.
>>>
>>>Tony
>>
>>I use incremental evaluation.
>>The only cases when I can be wrong in being lazy is in my qsearch because I do
>>not make every stupid capture in my qsearch.
>
>Why not ? If you make the supid capture and call quiescence, it will jump out of
>it because eval>beta.
>
>Anyway, since you have told here everal times that Movei doesn't have a complete
>eval yet, your experiences don't really impress ( not meant unfriendly !) The
>less knowledge your eval has, the better lazy eval works.
Perhaps it is a function of the structure of the eval function itself. Many
very good programs use lazy eval successfully, including:
Arasan
Averno
Crafty
Monsoon
Pepito
Sjeng
The Crazy Bishop
Yace
{Lots of others not as strong as these too, obviously}
If these very, very strong chess programs can profit from it, then perhaps it is
a function of how the evaluation itself is structured.
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