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From "Kim Haase (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-6083) Update minimum/maximum floating-point values to align with DERBY-3398 fixes
Date Wed, 20 Feb 2013 18:59:12 GMT

    [ https://issues.apache.org/jira/browse/DERBY-6083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13582414#comment-13582414
] 

Kim Haase commented on DERBY-6083:
----------------------------------

Thanks for the info about the values, Knut.

The terms "smallest" and "largest" seem to have been used in our documentation to refer to
positions on a number line, where "smallest" means "farthest to the left" and "largest" means
"farthest to the right". So we have been saying that the "Smallest DOUBLE" was -1.79769E+308,
while the "Largest DOUBLE" was the positive version of that, 1.79769E+308. Similarly, we called
-2.225E-307 the "Largest negative DOUBLE" because it's closest to zero.

This is confusing because we (I, anyway?) usually think of "smallest" and "largest" as referring
to magnitude, as defined by whether the exponent is negative or positive. So the closer a
number is to zero the smaller it is, whether negative or positive. The Java API docs for java.lang.Double
and java.lang.Float use this terminology. I think I'll try to get closer to the language used
there. This will involve using the terms "normalized" and "denormalized", but I don't think
that's a major issue. 
                
> 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
>
> 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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