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Subject: CM8k (& Rebel) Personality (Selectivity) Question

Author: Tina Long

Date: 20:59:55 04/06/01


Hi guys,
I've done all this before with Rebel Century, I worked for weeks, never formed a
 conclusion, so I went to Japan for some months to forget it all.
What I say below about CM8k can also be roughly translated to Rebel Century.
Century has the added benefits (complications) of ONite search syle & the like.


Following brief discussion of CM8k personalities in
http://www.icdchess.com/forums/1/message.shtml?161873
I tried a little research.

I'm interested in CM8k playing at 1 hour and 12 hours per move (from the old
Komputer Korner days) on a P3 1ghz computer.

I was using my Personality "CM128" default CM8k with 128m hash.(selectivity = 6)

I then tried the same with selectivity = 12
I then tried the same with selectivity = 2

At 12:  Depths reached were 1/11, 2/14 & the like.
At  2:  Depths reached were 7/9  10/12 & the like.

2: for the same positions, looked MUCH deeper at "brute force" and only SLIGHTLY
shallower at selective depth than 12:.

While most moves chosen were the same, when they differed I considered the 2:
were more sound (but then I'm just a dumb human) and more likely to agree with
Hiarcs732 & Tigger14.

What is the opinion of CCC people on the strength of the decisions made, in very
long time period games or analysis:

Is it better to have low selectivity and have a MUCH larger safer brute force
search?
Is it better to have high selectivity to have a SLIGHTLY deeper selective depth
search?
What's the benefit of that 1 or 2 extra ply compared to the risk of not checking
the full width beyond 1 or 2 plys?

I feel the results will differ depending on the particular positions, & I'd be
inclined to have high selectivity in the Early & Middle Game & lower selectivity
in the Endgame.

BUT I can quite easily see why just the opposite might be best.

Your Opinions will be appreciated,

See Ya
Tina Long






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