[R] Using functions in LAPACK in a C program

[Prof Brian Ripley]

I think all these points are answered in the README.packages for R 2.5.0 
alpha (and probably for 2.4.1 too).

You can use pexports to create Rlapack.exp, for example.

On Fri, 30 Mar 2007, pengp at queensu.ca wrote:

> Many thanks to Brian for his very useful information and help. A quick 
> look at mgcv package already gives me some directions to try. I remember 
> that I tried to use Rlapack.dll instead of R.dll without success, 
> perhaps because I don't know how to build an import library for 
> Rlapack.dll and link against it (README.packages shows how to do this 
> for R.dll using R.exp, but I could not find Rlapack.exp). I will try to 
> see if I can figure out this part using VC++6.0.
>
> Yes, I am still using R-2.2.1. I did try to upgrade it to R-2.4.1. 
> However, the newer versions cause some troubles for my C programs. They 
> produce error messages when my DLL are loaded into R. The problem 
> relates to function calls such as isfinite. I haven't figured out why my 
> C programs have this problem with newer versions of R but not with 
> version 2.2.1. I remember there was a post on this issue in this list, 
> but I did not see any solution. I hope to find a clue about it too so 
> that I can keep the pace of R development.
>
>
>
>
>
> Paul.
>
>
>
>
>
>
>
>
> ----- Original Message -----
>
>
> From: Prof Brian Ripley <ripley at stats.ox.ac.uk>
>
>
> Date: Friday, March 30, 2007 1:56 am
>
>
> Subject: Re: [R] Using functions in LAPACK in a C program
>
>
> To: Paul August <paulaugust2003 at yahoo.com>
>
>
> Cc: r-help at stat.math.ethz.ch
>
>
>
>
>
>> On Thu, 29 Mar 2007, Paul August wrote:
>
>
>>
>
>
>>> Hi,
>
>
>>>
>
>
>>> I wonder where I can find an example of using a function in
>
>
>> LAPACK
>
>
>>> library in a user's own C code.
>
>
>>
>
>
>> In about 20 R packages, e.g. the recommended package mgcv.
>
>
>>
>
>
>>> I wrote a C program which will be
>
>
>>> compiled and linked to produce a DLL file and then loaded into
>
>
>> R. I hope
>
>
>>> to use a function from LAPACK library, for example, dgesdd, in
>
>
>> the
>
>
>>> program. Following R manual, I call the function by
>
>
>> F77_CALL(dgesdd) in
>
>
>>> the program. The program can be compiled without problems.
>
>
>> However, when
>
>
>>> it is linked to produce a DLL file, I get an error message
>
>
>>>
>
>
>>>   Test.obj : error LNK2001: unresolved external symbol _dgesdd_
>
>
>>>   Test.dll : fatal error LNK1120: 1 unresolved externals
>
>
>>>
>
>
>>> I use VC++6.0 and the command of linking is something like this
>
>
>>>
>
>
>>>   link.exe Rdll.lib /nologo /dll /out:Test.dll
>
>
>> /libpath:C:\R\R-2.2.1\src\gnuwin32 Test.obj
>
>
>>>
>
>
>>> Apparently, the linker cannot resolve dgesdd from Rdll.lib. If
>
>
>> anyone
>
>
>>> knows what I missed here or any example that shows how this
>
>
>> can be done
>
>
>>> properly, please let me know. Thanks a lot.
>
>
>>
>
>
>> It is in Rlapack.dll not R.dll.
>
>
>>
>
>
>> The linking information is in 'Writing R Extensions' for those
>
>
>> using the
>
>
>> recommended compilation system (search for LAPACK_LIBS).
>
>
>>
>
>
>> You will need to build an import library for Rlapack.dll and
>
>
>> link against
>
>
>> that.
>
>
>>
>
>
>> And BTW you seem to be using R 2.2.1: please update as we can
>
>
>> only offer
>
>
>> accurate advice on recent systems.
>
>
>>
>
>
>> --
>
>
>> Brian D.
>
>
>> Ripley,                  ripley at stats.ox.ac.uk
>
>
>> Professor of Applied Statistics, 
>
>
>> http://www.stats.ox.ac.uk/~ripley/University of
>
>
>> Oxford,             Tel:  +44 1865 272861 (self)
>
>
>> 1 South Parks
>
>
>> Road,                     +44 1865 272866 (PA)
>
>
>> Oxford OX1 3TG,
>
>
>> UK                Fax:  +44 1865 272595
>
>
>>
>
>
>> ______________________________________________
>
>
>> R-help at stat.math.ethz.ch mailing list
>
>
>> https://stat.ethz.ch/mailman/listinfo/r-help
>
>
>> PLEASE do read the posting guide http://www.R-
>
>
>> project.org/posting-guide.html
>
>
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>>
>
> -----------------------------------------------
> Dr. Paul Y. Peng
> Associate Professor of Biostatistics
> Department of Community Health and Epidemiology
>   and Department of Mathematics and Statistics
> Queen's University, Kingston, ON, K7L 3N6
>
> Phone: 613-533-6000 Ext 78525
> Email: pengp at queensu.ca
> Fax: 613-533-6794
> -----------------------------------------------
>
> 	[[alternative HTML version deleted]]
>
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595