Author: Ed Schröder
Date: 11:09:44 12/30/02
Go up one level in this thread
On December 30, 2002 at 13:53:29, Martin Giepmans wrote:
>On December 30, 2002 at 13:23:29, Ed Schröder wrote:
>
>>On December 30, 2002 at 11:27:46, Martin Giepmans wrote:
>>
>>>>For free-style pseudo code it is defendable, maybe in more c-code style would
>>>>make it more clear?
>>>>
>>>> { if (ALPHA > SCORE + THREAT &&
>>>> ALPHA < SCORE + THREAT + MARGIN) -> reduce depth with one ply. }
>>>
>>>Yes, this makes it more clear.
>>
>>Okay, then I will make it that way.
>>
>>
>>>However, I wonder if the second part of the condition (the margin part)
>>>is useful. Maybe it is if the current window is smaller than margin, but
>>>otherwise?
>>
>>The idea is based on experience, not on logic, you know how it goes. It just
>>works for me.
>>
>Yes, I know :)
>>
>>>Of course, the extra condition makes the tric safer, but I think it could
>>>also cause more search instability.
>>
>>In my concept it hardly gave any trouble, but then the whole REBEL concept is
>>totally different. You will notice when I arrive on the issue null-move and how
>>I use it :)
>>
>>
>>>BTW, this probably doesn't work in an engine that uses PVS.
>>>Am I right?
>>
>>Please give the definition of PVS, I sometimes have the feeling there are more
>>than one definitions.
>>
>>Ed
>The version of PVS that I had in mind searches all moves except the first
>with a minimal window (alpha, alpha+1).
I use something close to PVS, see:
http://members.home.nl/matador/chess840.htm#SEARCH
I have experimented with PVS and it gave me nothing, but PVS did not harm the
reductions. What certainly will harm the reductions as I use them is (standard)
null-move, see the warning I gave in the introduction.
But you know, this stuff demands a whole different way of thinking, that's
always good, it might pay off later.
Ed
>Martin
>>
>>>Cheers,
>>>Martin
>>>
>>>>
>>>>ALPHA=100
>>>>SCORE=90
>>>>THREAT=0
>>>>MARGIN=20
>>>>
>>>>-> reduction
>>>>
>>>>ALPHA=100
>>>>SCORE=60
>>>>THREAT=0
>>>>MARGIN=20
>>>>
>>>>-> no reduction
>>>>
>>>>Ed
>>>>
>>>>
>>>>>Martin
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