[jira] [Commented] (LUCENE-7594) Float/DoublePoint should not recommend using Math.nextUp/nextDown for exclusive ranges

["Dawid Weiss (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LUCENE-7594?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15751994#comment-15751994 ] 

Dawid Weiss commented on LUCENE-7594:
-------------------------------------

Ah, that is trappy... In a way it makes sense as -0.0f is 8000_0000 and min value is 0000_0001, so if you disregard the sign bit there's some logic there. 

Patch looks good. I don't know if the compiler will be smart enough to avoid recomputing the static {{Float.floatToIntBits(-0f)}}. An alternative would be to:
{code}
if (Float.compare(f, -0.0) == 0)
{code}
or simply compare the int representation (Float.toIntBits(f) == 0x8000_0000). Either way, looks good to me.


> Float/DoublePoint should not recommend using Math.nextUp/nextDown for exclusive ranges
> --------------------------------------------------------------------------------------
>
>                 Key: LUCENE-7594
>                 URL: https://issues.apache.org/jira/browse/LUCENE-7594
>             Project: Lucene - Core
>          Issue Type: Bug
>            Reporter: Adrien Grand
>            Priority: Minor
>         Attachments: LUCENE-7594.patch
>
>
> Float/Double points are supposed to be consistent with Double/Float.compare, so +0 is supposed to compare greater than -0. However Math.nextUp/nextDown is not consistent with Double/Float.compare and returns MIN_VALUE for nextUp(-0).



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