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From "Nicholas Knize (JIRA)" <>
Subject [jira] [Commented] (LUCENE-7179) GeoPoint and LatLonPoint test data should quantize once
Date Tue, 05 Apr 2016 14:26:25 GMT


Nicholas Knize commented on LUCENE-7179:

This is not an issue for existing LatLonPoint or GeoPointField because:

1. LatLonPoint uses {{0x1L << 32 / 360.0}} and handles overflow for {{90.0}} {{180.0}}
by calling {{Math.nextDown}}.
2. GeoPointField uses 31 bits and tolerance 1e-6. So overflow is not a problem.

When switching to a morton encoding which maps {{-90.0, -180.0}} to {{0L}} and {{90.0, 180.0}}
to {{0xFFFFF...}} round off error becomes a problem when points are quantized more than once.
 I will add the LUCENE-7165 patch along with a test to show this.  

> GeoPoint and LatLonPoint test data should quantize once
> -------------------------------------------------------
>                 Key: LUCENE-7179
>                 URL:
>             Project: Lucene - Core
>          Issue Type: Bug
>            Reporter: Nicholas Knize
> {{LatLonPoint}} and {{GeoPointField}} tests pre quantizes test data to ensure consistency
with indexed (encoded) data. The pre quantized data then becomes indexed, undergoing another
quantization. To guarantee numerical stability this should be changed such that the test data
is quantized after indexing.

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