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From "Heinrich Bohne (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (NUMBERS-119) BigFraction(double) constructor does not treat subnormal numbers correctly
Date Mon, 01 Jul 2019 00:02:00 GMT

    [ https://issues.apache.org/jira/browse/NUMBERS-119?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16875888#comment-16875888
] 

Heinrich Bohne commented on NUMBERS-119:
----------------------------------------

Excellent, thanks! Regarding NUMBERS-123 and 124: I found one missed Javadoc update, for which
I'll create a pull request. Or is a patch preferable for such trivial changes? I'll create
a patch too, if I manage to upload it in NUMBERS-123.

> BigFraction(double) constructor does not treat subnormal numbers correctly
> --------------------------------------------------------------------------
>
>                 Key: NUMBERS-119
>                 URL: https://issues.apache.org/jira/browse/NUMBERS-119
>             Project: Commons Numbers
>          Issue Type: Bug
>          Components: fraction
>    Affects Versions: 1.0
>            Reporter: Heinrich Bohne
>            Priority: Minor
>             Fix For: 1.0
>
>          Time Spent: 1h 20m
>  Remaining Estimate: 0h
>
> The constructor {{BigFraction(double)}} does not take into account the fact that, when
the biased exponent of a {{double}} value is {{0}} and the mantissa is not {{0}} (i.e. when
the value represents a subnormal number), the actual exponent in effect is not {{-1023}} but
{{-1022}} (or, in other words, the effective exponent bias is not {{1023}} but {{1022}}).
> The value of the created {{BigFraction}} is therefore not equal to the value of the passed
{{double}} argument.
> Also, since the constructor does not handle the case of zero separately, it creates a
fraction with a numerator of 0 and a denominator of 2^1075^, which is not very memory-efficient.



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