On Tue, Sep 17, 2019 at 4:16 PM Brian Sheppard via Computer-go <
> I remember a scheme (from Dave Dyer, IIRC) that indexed positions based on
> the points on which the 20th, 40th, 60th,... moves were made. IIRC it was
> nearly a unique key for pro positions.
> -----Original Message-----
> From: Erik van der Werf <erikvanderw...@gmail.com>
> To: computer-go <email@example.com>
> Sent: Tue, Sep 17, 2019 5:55 am
> Subject: Re: [Computer-go] Indexing and Searching Go Positions --
> Literature Wanted
> Hi Stephen,
> I'm not aware of recent published work. There is an ancient document by
> Antti Huima on hash schemes for easy symmetry detection/lookup.
> Unfortunately his implementation was broken, but other schemes have been
> proposed that solve the issue (I found one myself, but I think many others
> found the same or similar solutions). You may want to search the archives
> for "Zobrist hashing with easy transformation comparison". If you like math
> Nic Schrauolph has an interesting solution ;-)
> In Steenvreter I implemented a 16-segment scheme with a xor update (for
> rotation, mirroring and color symmetry). In GridMaster I have an
> experimental search feature which is somewhat similar except that I don't
> use hash keys (every possible point on the board simply gets its own bits),
> and I use 'or' instead of 'xor' (so stones that are added are never
> removed, which makes parsing game records extremely fast). This makes it
> very easy to filter positions/games that cannot match, and for the
> remainder (if needed, dealing with captures) it simply replays (which is
> fast enough because the number of remaining games is usually very small).
> I'm not sure what Kombilo does, but I wouldn't be surprised if it's
> similar. The only thing I haven't implemented yet is lookup of translated
> (shifted) local patterns. Still pondering what's most efficient for that,
> but I could simply run multiple searches with a mask.
> On Tue, Sep 17, 2019 at 10:17 AM Stephen Martindale <
> stephen.c.martind...@gmail.com> wrote:
> > Dear Go programmers,
> > I'm interested in experimenting with some new ideas for indexing and
> searching Goban positions and patterns and I want to stand on the shoulders
> of giants. Which papers, articles, blog posts or open-source code should I
> read to get concrete knowledge of the approaches used in the past?
> > I know that Kombilo is (or used to be) the state of the art in this
> field. The source is available but, beyond reading the Libkombilo sources,
> are there any other, more human friendly resources out there?
> > My new ideas are currently insubstantial and vague but I have done some
> work, in the past, with natural language embeddings and large-database
> image indexing and searching and concepts from those two domains keep
> bouncing around in my mind -- I can't help but feel that there must be
> something there that can be the "next big thing" in Go position indexing.
> > Any leads would be appreciated.
> > Stephen Martindale
> > +49 160 950 27545
> > stephen.c.martind...@gmail.com
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