[Rcpp-devel] basic usage help

[Romain Francois]

Le 27/05/10 05:07, Vinh Nguyen a écrit :
> On Wed, May 26, 2010 at 6:31 PM, Davor Cubranic<cubranic at stat.ubc.ca>  wrote:
>> On 2010-05-26, at 4:08 PM, Vinh Nguyen wrote:
>>> Also, I didn't include BLAS or LAPACK linking -- still don't know how
>>> to get the compilation flags easily.   I read the skeleton stuff but I
>>> don't understand (sorry).
>>
>> Just put in your package's 'src' directory the Makevars file that's generated by RcppArmadillo's package.skeleton function. This is what it looks like on my machine:
>>
>> PKG_LIBS = $(shell $(R_HOME)/bin/Rscript -e "Rcpp:::LdFlags()" ) $(LAPACK_LIBS) $(BLAS_LIBS) $(FLIBS)
>>
>> How do you compile the code, by the way? It sounds like you do it by hand. Why not let R do it? With the above Makevars and the correct 'Depends' line in your package description (again, see the skeleton), you won't have to muck about with compiler switches and lookup paths, and everything should 'just work'.
>>
>> Davor
>
> Yes, I'm doing it by hand since I'm still coding.  I compile after
> some progress to make sure everything is OK.

It is not much longer to compile a package is it ?

> Let's say I place the my code in in /src.  Do I HAVE to turn this into
> a package in order to compile?  Or is there a way to compile from
> here.  Sorry I'm new at this approach.

You don't have to, but it makes your life easier. Now that we use 
LinkingTo: Rcpp, RcppArmadillo it makes our Makevars smaller and more 
robust. R figures out on its own where to find Rcpp and RcppArmadillo 
include paths.

If you don't want to use what R and Rcpp provides for you, you can 
emulate this by using this Makevars :

PKG_LIBS = $(shell $(R_HOME)/bin/Rscript -e "Rcpp:::LdFlags()" ) 
$(LAPACK_LIBS) $(BLAS_LIBS) $(FLIBS)
PKG_CXXFLAGS = $(shell $(R_HOME)/bin/Rscript -e "Rcpp:::CxxFlags()" ) 
$(shell Rscript -e "cat( '-I', system.file('include', package = 
'RcppArmadillo'), sep = '' )" )


The PKG_LIBS line is the same that the one that gets generated  by 
RcppArmadillo.package.skeleton.

The PKG_CXXFLAGS line pulls in the include path of Rcpp and RcppArmadillo.

Just save this as a "Makevars" in the directory where your cpp files 
are, and run:

R CMD SHLIB *cpp -o mylib.so


I will add a RcppArmadillo:::CxxFlags() for consistency between Rcpp and 
RcppArmadillo.

Romain

> Thanks.
>
> Vinh


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Romain Francois
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