| From: | Andrew Borodin <borodin(at)octonica(dot)com> |
|---|---|
| To: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Михаил Бахтерев <mike(dot)bakhterev(at)gmail(dot)com> |
| Subject: | Re: GiST penalty functions [PoC] |
| Date: | 2016-09-07 07:06:52 |
| Message-ID: | CAJEAwVG=Ws8rJaeG14wCj5rzBN_5L_v+xM87XzEmaO9eqbh3Lw@mail.gmail.com |
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| Lists: | pgsql-hackers |
Oh, sorry, made one more attemp and now I see your algorithm differently.
So you propose to use oE and oV as a markers of borders for what I call Realm.
But there may be very little significant bits in one of this ranges.
pg_sphere and PostGiS extensions tried to use 1 as a marker, with
alike formula. And that generated not a good tree.
Here's how they done it
https://github.com/postgis/postgis/commit/9569e898078eeac8928891e8019ede2cbf27d06f
I'll try to compose a patch for your formula later, I think we should
just try and see, it is easier than to reason about digital floating
points.
Best regards, Andrey Borodin, Octonica & Ural Federal University.
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