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https://issues.apache.org/jira/browse/MATH-502?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Luc Maisonobe resolved MATH-502.
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Resolution: Fixed
fixed in subversion repository as of r1062928 for trunk and r1062929 for branch
2.X
> FastMath scalb() does not handle large magnitude exponents correctly
> --------------------------------------------------------------------
>
> Key: MATH-502
> URL: https://issues.apache.org/jira/browse/MATH-502
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 2.2, 3.0
> Reporter: Sebb
> Fix For: 2.2, 3.0
>
>
> scalb does not handle MAX_VALUE exponents properly:
> double scalb(-1.7976931348623157E308, 2147483647) expected -Infinity actual
> -8.988465674311579E307 entries [6, 5]
> double scalb(1.7976931348623157E308, 2147483647) expected Infinity actual
> 8.988465674311579E307 entries [7, 5]
> double scalb(-1.1102230246251565E-16, 2147483647) expected -Infinity actual
> -5.551115123125783E-17 entries [8, 5]
> double scalb(1.1102230246251565E-16, 2147483647) expected Infinity actual
> 5.551115123125783E-17 entries [9, 5]
> double scalb(-2.2250738585072014E-308, 2147483647) expected -Infinity actual
> -0.0 entries [10, 5]
> double scalb(2.2250738585072014E-308, 2147483647) expected Infinity actual
> 0.0 entries [11, 5]
> float scalb(3.4028235E38, 2147483647) expected Infinity actual 1.7014117E38
> entries [7, 5]
> float scalb(-3.4028235E38, 2147483647) expected -Infinity actual
> -1.7014117E38 entries [9, 5]
> It looks as though the problem is with the calculation of the scaledExponent
> - for large values, this can wrap round, so some of the checks against its
> value may give misleading results.
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