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From "Karl Wright (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-6759) Integrate lat/long BKD and spatial 3d, part 2
Date Thu, 27 Aug 2015 22:56:45 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-6759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14717707#comment-14717707
] 

Karl Wright commented on LUCENE-6759:
-------------------------------------

[~mikemccand]: So, your code:

{code}
    long y = (long) (x * (Integer.MAX_VALUE / max));
{code}

... can be rewritten:

{code}
    long y = (long) (x / max * Integer.MAX_VALUE);
{code}

So it is basically scaling so that Integer.MAX_VALUE is returned for a value of max.  So far
so good.

But in order to do that, it's rounding down for positive numbers, and rounding up for negative
ones.  So:

1.5 -> 1
1.1 -> 1
1.9 -> 1
2.1 -> 2
-1.5 -> -1
-1.9 -> -1

But:
0.9 -> 0
-0.9 -> 0

So, the cell at 0 is in fact representing a range that is twice as great as the cell at 1
or the cell at -1.  I'm not sure you really want that. ;-)






> Integrate lat/long BKD and spatial 3d, part 2
> ---------------------------------------------
>
>                 Key: LUCENE-6759
>                 URL: https://issues.apache.org/jira/browse/LUCENE-6759
>             Project: Lucene - Core
>          Issue Type: New Feature
>            Reporter: Michael McCandless
>         Attachments: LUCENE-6699.patch, LUCENE-6699.patch, LUCENE-6699.patch, LUCENE-6699.patch,
LUCENE-6699.patch, LUCENE-6699.patch, LUCENE-6699.patch
>
>
> This is just a continuation of LUCENE-6699, which became too big.



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