[R-pkg-devel] [External] Re: incomplete gamma function Fortran subroutine

[Wang, Zhu]

Indeed, that is the piece I missed completely! Glad that I didn't try to invent wheels.
Thanks,
Zhu

-----Original Message-----
From: Ben Bolker <bbolker using gmail.com> 
Sent: Tuesday, July 21, 2020 3:58 PM
To: luke-tierney using uiowa.edu; Wang, Zhu <wangz1 using uthscsa.edu>
Cc: John P. Nolan <jpnolan using american.edu>; r-package-devel using r-project.org
Subject: Re: [External] Re: [R-pkg-devel] incomplete gamma function Fortran subroutine

   Interesting.  It looks like the way to make use of this is to combine the information in section 6.7.1 ("Distribution functions", including pgamma ...) with section 6.6 "Calling C from Fortran and vice versa" ?

On 7/21/20 4:33 PM, luke-tierney using uiowa.edu wrote:
> Looking at this section of WRE may help:
>
> https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Numerical
> -analysis-subroutines
>
>
> Best,
>
> luke
>
> On Tue, 21 Jul 2020, Wang, Zhu wrote:
>
>> Thanks to Ben and John. Perhaps the program should call pgamma in R 
>> and pass the number to Fortran. Calling some Fortran subroutines 
>> older than R can trigger concerns when submitting the package to the 
>> CRAN.
>>
>> Best,
>> Zhu
>>
>> -----Original Message-----
>> From: John P. Nolan <jpnolan using american.edu>
>> Sent: Tuesday, July 21, 2020 1:43 PM
>> To: Wang, Zhu <wangz1 using uthscsa.edu>; Ben Bolker <bbolker using gmail.com>; 
>> r-package-devel using r-project.org
>> Subject: RE: [R-pkg-devel] incomplete gamma function Fortran 
>> subroutine
>>
>> As others have said, built-in function pgamma is a (normalized) 
>> version of the incomplete gamma function!   John
>>
>> -----Original Message-----
>> From: R-package-devel <r-package-devel-bounces using r-project.org> On 
>> Behalf Of Wang, Zhu
>> Sent: Tuesday, July 21, 2020 2:16 PM
>> To: Ben Bolker <bbolker using gmail.com>; r-package-devel using r-project.org
>> Subject: Re: [R-pkg-devel] incomplete gamma function Fortran 
>> subroutine
>>
>> External Email: Use caution with links and attachments.
>>
>> Sorry for not making myself clear: The Fortran subroutine in an R 
>> package needs to call incomplete gamma function.
>>
>> -----Original Message-----
>> From: R-package-devel <r-package-devel-bounces using r-project.org> On 
>> Behalf Of Ben Bolker
>> Sent: Tuesday, July 21, 2020 12:54 PM
>> To: r-package-devel using r-project.org
>> Subject: Re: [R-pkg-devel] incomplete gamma function Fortran 
>> subroutine
>>
>>     Is there a reason not to use pgamma(), possibly adjusted by a 
>> (de-)normalizing constant?   (See detailed notes in ?pgamma)
>>
>> On 7/21/20 1:44 PM, Wang, Zhu wrote:
>>> Hello,
>>>
>>> In an R function within a package, I would like to call a Fortran 
>>> subroutine to compute lower gamma function. Any advice will be 
>>> appreciated.
>>>
>>> Thanks!
>>>
>>> Zhu Wang
>>>
>>>       [[alternative HTML version deleted]]
>>>
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