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From "Kim Haase (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-3874) Document numeric function ATAN2(float1,float2)
Date Mon, 22 Sep 2008 21:40:44 GMT

    [ https://issues.apache.org/jira/browse/DERBY-3874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12633515#action_12633515
] 

Kim Haase commented on DERBY-3874:
----------------------------------

Thanks, Kristian -- the Java API docs are useful as long as I remember that infinities and
positive and negative zero aren't really applicable -- I think. Not in SQL; I need to try
some Java programs. I can't think how you would specify infinity as an argument. You can't
get it as a result.

ij> values(log(0));
ERROR 22003: The resulting value is outside the range for the data type DOUBLE.

This means that a couple of the quadrants in potential atan2 results aren't available. 

I notice I can specify +0 and -0 as arguments with no error, but plain old 0.0 is always returned
even if the value should be -0:

ij> values(asin(-0));
1                     
----------------------
0.0            

We probably should correct what is currently in the Ref Manual for asin and atan, since they
say "the result of this function is zero with the same sign as the specified number" and this
doesn't seem to be the case.

Anyway, the large number of possibilities in the Java API doc is reduced considerably when
you eliminate the arguments that aren't applicable, I think.

> Document numeric function ATAN2(float1,float2)
> ----------------------------------------------
>
>                 Key: DERBY-3874
>                 URL: https://issues.apache.org/jira/browse/DERBY-3874
>             Project: Derby
>          Issue Type: Sub-task
>          Components: Documentation
>    Affects Versions: 10.5.0.0
>            Reporter: Kristian Waagan
>            Assignee: Kim Haase
>
> Document the numeric function ATAN2(float1,float2).
> Mentioned in the JDBC specification, appendix C.1.
> Implementation documented by the JavaDoc for StrictMath.atan2.
> According to the JDBC specification, table B-1, a JDBC float maps to a Java double.

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