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https://issues.apache.org/jira/browse/NUMBERS-219?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alex Herbert updated NUMBERS-219:
---------------------------------
Description:
The Digamma and Trigamma functions currently return the input argument if it is
not finite. NaN is returned as NaN and infinity is returned as the same
infinity. These infinite limits are not correct.
||Function||Argument||Limit||Return||
|Digamma|-infinity|Has infinite poles at integer values.
As x moves toward negative infinity along the real axis,
it repeatedly crosses these infinite poles and oscillates between + and -
infinity.
The value diverges and has no limit.|NaN|
|Digamma|infinity|The function grows (logarithmically) without bound to
infinity|infinity|
|Trigamma|-infinity|As for the digamma function, the real-valued trigamma
function
features infinite poles at all non-positive integers.
Between these poles it oscillates and does not have a simple limit.|NaN|
|Trigamma|infinity|The function decays asymptotically like 1 / x towards
zero.|0|
was:
The Digamma and Trigamma functions currently return the input argument if it is
not finite. NaN is returned as NaN and infinity is returned as the same
infinity. These infinite limits are not correct.
||Function||Argument||Limit||Return||
|Digamma|-infinity|Has infinite poles at integer values. As x moves toward
negative infinity along the real axis, it repeatedly crosses these infinite
poles and oscillates between + and - infinity. The value diverges and has no
limit.|NaN|
|Digamma|infinity|The function grows (logarithmically) without bound to
infinity|infinity|
|Trigamma|-infinity|As for the digamma function, the real-valued trigamma
function features infinite poles at all non-positive integers. Between these
poles it oscillates and does not have a simple limit.|NaN|
|Trigamma|infinity|The function decays asymptotically like 1 / x towards
zero.|0|
> Digamma and Trigamma limits at -infinity are unspecified; at +infinity are
> defined
> ----------------------------------------------------------------------------------
>
> Key: NUMBERS-219
> URL: https://issues.apache.org/jira/browse/NUMBERS-219
> Project: Commons Numbers
> Issue Type: Improvement
> Components: gamma
> Affects Versions: 1.0
> Reporter: Alex Herbert
> Priority: Trivial
>
> The Digamma and Trigamma functions currently return the input argument if it
> is not finite. NaN is returned as NaN and infinity is returned as the same
> infinity. These infinite limits are not correct.
> ||Function||Argument||Limit||Return||
> |Digamma|-infinity|Has infinite poles at integer values.
> As x moves toward negative infinity along the real axis,
> it repeatedly crosses these infinite poles and oscillates between + and -
> infinity.
> The value diverges and has no limit.|NaN|
> |Digamma|infinity|The function grows (logarithmically) without bound to
> infinity|infinity|
> |Trigamma|-infinity|As for the digamma function, the real-valued trigamma
> function
> features infinite poles at all non-positive integers.
> Between these poles it oscillates and does not have a simple limit.|NaN|
> |Trigamma|infinity|The function decays asymptotically like 1 / x towards
> zero.|0|
>
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