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Re: [Bug-gnubg] Bug in makebearoff when building db w/o gammons
From: |
Øystein Johansen |
Subject: |
Re: [Bug-gnubg] Bug in makebearoff when building db w/o gammons |
Date: |
Sun, 01 Mar 2009 11:23:48 +0100 |
User-agent: |
Thunderbird 2.0.0.19 (Windows/20081209) |
Øystein Johansen (OJOHANS) wrote:
> Hi all!
>
> There's a bug in makebearoff when building one sided databases without
> gammon distributions.
> ERROR:makebearoff.c:483:BearOff: assertion failed: (iGammonBest >= 0)
>
> I think it's just a matter of removing the assert() or set iGammonBest
> when building w/o gammon distributions.
I've committed a patch which removes the assert. I've also reduced the
size of each index entry for compressed database w/o gammon
distributions. This means that if someone is using a gammonless onesided
bearoff database (which is not very likely), the database evaluations
will be broken unless they build a new.
For discussion:
For bearoff databases with gammon distributions, the db stores gammon
distributions for _all_ positions in the db. Even those positions where
a gammon is already saved. It uses only 2 bytes for such positions, but
I'm estimating that there is about > 20000 positions where there is no
gammon involved. Making a scheme to check for possible gammon and only
storing those distributions sounds trivial, but is it worth the effort?
If I commit such change, it will break compatibility with existing
bearoff databases, but the memory footprint will be 40-50Kb less. Is it
worth it?
-Øystein
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- Re: [Bug-gnubg] Bug in makebearoff when building db w/o gammons,
Øystein Johansen <=