[jira] [Created] (LUCENE-7160) LatLonPoint quantization should use same rounding mode as GeoPointField

["Robert Muir (JIRA)" <ji...@apache.org>]

Robert Muir created LUCENE-7160:
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             Summary: LatLonPoint quantization should use same rounding mode as GeoPointField
                 Key: LUCENE-7160
                 URL: https://issues.apache.org/jira/browse/LUCENE-7160
             Project: Lucene - Core
          Issue Type: Bug
            Reporter: Robert Muir


Both of these fields quantize doubles in a lossy way, but GeoPoint rounds towards negative infinity (because all values get shifted to positive space first), whereas LatLonPoint currently rounds towards zero.

At the same time they share the same basic logic for e.g. tree traversal and same basic tests: so it creates confusion that they round differently.

Especially since e.g. LatLonPoint does some operations in binary/integer space (some of these optimizations such as its box query are currently buggy for edge cases, and tests are lenient as TODO, another issue, may or may not impact GeoPoint, it at least tries harder).

I think LatLonPoint should round down to be more like GeoPoint here? By the way, doing this also gives more consistency, it reduces the difference between the two implementations in e.g. openstreetmaps searching (distance query benchmark now differs by only 4 hits...)

This quantization makes things complicated to reason about. I understand the advantages it brings but I think along with that comes the responsibility of us handling edge cases better. I don't think we do well at this today...



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