Re: [Bug-gnubg] Why is odd ply equity always lower?

[Ned Cross]

----- Original Message ----- 
From: "Ian Shaw" <address@hidden>
To: "Nis" <address@hidden>; <address@hidden>
Sent: Thursday, June 19, 2003 3:59 AM
Subject: RE: [Bug-gnubg] Why is odd ply equity always lower?


> ---
>
> Only relevant for cube decisions?
>
> The wrong estimations of equity is mainly a problem of
> absolute equities.
> As Joseph has pointed out, chequerplay relies almost solely
> on the relative equities of positions.
>
> Thus a fix should only "need" to be applied for cube
> decisions (and cubeful
> chequerplay? Someone help me here)
>

A possible result of this even/odd ply equity discrepancy is GNU's cube
decisions in many situations.  I haven't been keeping a log, but I notice
numerous positions where GNU 2-ply evaluates double/take (usually somewhere
between 0.850 and 0.900) and GNU 3-ply evaluates double/pass (usually
somewhere between 1.000 and 1.100).  The difference seems to always be in
the same direction.

Ned