Thanks Uwe
I am not quite sure I understand.
To clarify, do you mean writing my R functions as something like:
functionRequiringGsl <- function(arg1, arg2)
{
if(require(gsl))
{
## Some functions that use GSL
## called using .C()
} else {
stop("GSL not available")
}
}
If so, I still don't understand what happens when I compile the package if GSL
is not installed on the computer, as there will still be C code in the src
directory.
Thanks again
Erika
On 17 Aug 2012, at 12:35, Uwe Ligges wrote:
>
>
> On 17.08.2012 11:11, Cule, Erika wrote:
>> I have written an R package which contains C source code (in the directory
>> pkg/src).
>>
>> Only a subset of the functions in the pkg/R directory contain a .C() call to
>> the functions in the pkg/src directory. The rest of the package will still
>> work and be useful without the functions containing a .C() call.
>>
>> To compile the code in pkg/src requires the GSL library. This is detailed in
>> the SystemRequirements line of the DESCRIPTION file and the Makevars file
>> directs the compiler to LIB_GSL.
>>
>> At what stage will installation fail for the end user if they don't have GSL
>> installed?
>>
>> I have used Autoconf and configure, following the example in 1.2 of "Writing
>> R Extensions" and the configure.ac file in the R package gsl, to detect
>> whether the GSL library is installed on the computer and disable the R
>> functions if the GSL library is not found (by using a TRUE/FALSE pattern
>> substitution, as in the example in "Writing R Extensions"). If GSL is not
>> available, will the package now install on another users machine with these
>> functions disabled? Or upon installation will the installer try to install
>> the code in pkg/src and fail because the libraries are not available?
>
> Yes, you have to work around the installation steps that compile and link
> your C sources and then the call to dynload the shared library in R.
>
> It is porbably easier to use the gsl library via the gsl package, given it
> ptovides the gsl functionality you are using. In that case, you just need to
> suggest the gsl package an load it for the one function on demand only.
>
> Best,
> Uwe ligges
>
>
>> Is there a practical way to test this? Both of the computers I have access
>> to have GSL available, and installation works whether I set HAVE_GSL=TRUE or
>> HAVE_GSL=FALSE (although in the latter case the corresponding R functions
>> are disabled).
>>
>> I hope that this is clear, and am happy to post my code if it would be
>> useful.
>>
>> Many thanks in advance.
>>
>> Erika
>>
>> ---
>>
>> Erika Cule
>> PhD student in Statistical Genetics
>> Imperial College London
>> Department of Epidemiology and Public Health
>> erika.cul...@imperial.ac.uk
>> http://occamstypewriter.org/erikacule/
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
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