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From "Dag H. Wanvik (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-6083) Update minimum/maximum floating-point values to align with DERBY-3398 fixes
Date Fri, 22 Feb 2013 07:36:12 GMT

    [ https://issues.apache.org/jira/browse/DERBY-6083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13584058#comment-13584058
] 

Dag H. Wanvik commented on DERBY-6083:
--------------------------------------

Yes, we do, cf. test below:

  ij> values -0.0;
  1   
  ----
  0.0 

  1 row selected
  ij> values asin(-0.0);
  1                       
  ------------------------
  0.0 

It can also be seen in the code in NumberDataType#normalize{Real,Double}:

  // Normalize negative floats to be "positive" (can't detect easily
  // without using Float object because -0.0f = 0.0f)
  // DERBY-2447: It shouldn't matter whether we compare to 0.0d or -0.0d,
  // both should match negative zero, but comparing to 0.0d triggered
  // this JVM bug: http://bugs.sun.com/view_bug.do?bug_id=6833879
  if (fv == -0.0f) {
      fv = 0.0f;
  }

So it would seem the docs are wrong here.
                
> Update minimum/maximum floating-point values to align with DERBY-3398 fixes
> ---------------------------------------------------------------------------
>
>                 Key: DERBY-6083
>                 URL: https://issues.apache.org/jira/browse/DERBY-6083
>             Project: Derby
>          Issue Type: Task
>          Components: Documentation
>    Affects Versions: 10.10.0.0
>            Reporter: Kim Haase
>            Assignee: Kim Haase
>            Priority: Minor
>         Attachments: DERBY-6083.diff, DERBY-6083.stat, DERBY-6083.zip
>
>
> The limits for floating-point values have changed as a result of DERBY-3398 and should
be documented:
> Smallest DOUBLE: 4.9e-324 (aka Double.MIN_VALUE)
> Largest DOUBLE: 1.7976931348623157e+308 (aka Double.MAX_VALUE)
> Smallest positive DOUBLE: 2.2250738585072014E-308 (aka Double.MIN_NORMAL)
> Largest negative DOUBLE: -2.2250738585072014E-308
> Smallest REAL: 1.4e-45 (aka Float.MIN_VALUE)
> Largest REAL: 3.4028235e+38 (aka Float.MAX_VALUE)
> Smallest positive REAL: 1.17549435E-38 (aka Float.MIN_NORMAL)
> Largest negative REAL: -1.17549435E-38 

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