[Rcpp-devel] Fwd: Rcpp and rpy2

[Dirk Eddelbuettel]

On 12 August 2011 at 14:33, Jonas Rauch wrote:
| Hi Dirk and Romain,
| 
| Aparrently libR is not loaded by rpy2, at least not in a way such that Rcpp can
| access it. I have solved the problem by adding -lR to the linker flags when
| building Rcpp. Since for normal use of Rcpp from R this does not make a
| difference, would you mind adding this to the Makevars file in a future version
| of Rcpp? Or does this lead to problems in case R is build without libR.so?

I would be somewhat hesitant to do so as it may affect all users of Rcpp.

Rcpp is for getting code into R, and we can take libR as given as R is always
around when loading Rcpp.  I think the problem is really with the linker and
passing symbols through from one end to the other.

Other views, anyone?

Dirk


| Best regards,
| Jonas
| 
| ---------- Forwarded message ----------
| From: Jonas Rauch <jonas.rauch at googlemail.com>
| Date: Fri, Aug 12, 2011 at 10:36 AM
| Subject: Rcpp and rpy2
| To: rcpp-devel <rcpp-devel at r-forge.wu-wien.ac.at>
| 
| 
| Is Rcpp compatible with rpy2?
| I would like to call a very complex R function from python. My function depends
| on code implemented with Rcpp. When I try to load Rcpp from python via
| 
| import rpy2.robjects as robjects
| robjects.r('library(Rcpp)')
| 
| I get the following:
| 
| Error in dyn.load(file, DLLpath = DLLpath, ...) :
|   unable to load shared object '/home/jonas/R/x86_64-unknown-linux-gnu-library
| /2.13/Rcpp/libs/Rcpp.so':
|   /home/jonas/R/x86_64-unknown-linux-gnu-library/2.13/Rcpp/libs/Rcpp.so:
| undefined symbol: R_ClassSymbol
| Error: package/namespace load failed for 'Rcpp'
| Traceback (most recent call last):
|   File "RcppTest.py", line 2, in <module>
|     robjects.r('library(Rcpp)')
|   File "/usr/local/lib/python2.7/dist-packages/
| rpy2-2.2.2dev_20110811-py2.7-linux-x86_64.egg/rpy2/robjects/__init__.py", line
| 225, in __call__
|     res = self.eval(p)
|   File "/usr/local/lib/python2.7/dist-packages/
| rpy2-2.2.2dev_20110811-py2.7-linux-x86_64.egg/rpy2/robjects/functions.py", line
| 82, in __call__
|     return super(SignatureTranslatedFunction, self).__call__(*args,
| **kwargs)
|   File "/usr/local/lib/python2.7/dist-packages/
| rpy2-2.2.2dev_20110811-py2.7-linux-x86_64.egg/rpy2/robjects/functions.py", line
| 34, in __call__
|     res = super(Function, self).__call__(*new_args, **new_kwargs)
| rpy2.rinterface.RRuntimeError: Error: package/namespace load failed for 'Rcpp'
| 
| From what I understand R_ClassSymbol is supplied by libR.so, which should by
| loaded by rpy2 anyway in order to work at all, or am I totally wrong here?
| 
| Running python 2.7.1, rpy2-2.2.2, R 2.13.0
| I would appreciate any help.
| 
| Regards,
| Jonas
| 
| 
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