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https://issues.apache.org/jira/browse/NUMBERS-172?focusedWorklogId=667475&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-667475
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ASF GitHub Bot logged work on NUMBERS-172:
------------------------------------------

                Author: ASF GitHub Bot
            Created on: 20/Oct/21 07:18
            Start Date: 20/Oct/21 07:18
    Worklog Time Spent: 10m 
      Work Description: aherbert opened a new pull request #108:
URL: https://github.com/apache/commons-numbers/pull/108


   Replace the use of the regularized gamma functions P and Q to evaluate
   the error function.


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Issue Time Tracking
-------------------

            Worklog Id:     (was: 667475)
    Remaining Estimate: 0h
            Time Spent: 10m

> Update the Erf function to use the Boost rational function approximtion
> -----------------------------------------------------------------------
>
>                 Key: NUMBERS-172
>                 URL: https://issues.apache.org/jira/browse/NUMBERS-172
>             Project: Commons Numbers
>          Issue Type: Improvement
>          Components: gamma
>    Affects Versions: 1.0
>            Reporter: Alex Herbert
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> The error function (erf) and complementary error function (erfc) are 
> implemented using the continued fraction evaluation performed in the 
> regularized gamma P and Q implementation. This is a generic function called 
> with a fixed argument of 0.5:
> {noformat}
> erf(x)  = gammap(0.5, x*x)
> erfc(x) = gammaq(0.5, x*x)
> {noformat}
> These functions have an implementation in the Boost c++ library using a 
> rational function approximation.
> NUMBERS-171 ported the inverse erf functions from Boost with an improvement 
> in accuracy and speed. Investigate the use of the corresponding forward erf 
> and erfc functions from Boost as replacements for the use of the regularized 
> gamma function to evaluate the error function.



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