[Rcpp-devel] Fwd: Rcpp and rpy2

[Dirk Eddelbuettel]

On 15 August 2011 at 10:00, Jonas Rauch wrote:
| Just to close this up:
| I found out that my Rcpp installation must have occured when my R was not built
| with shared lib. Thus Rcpp was not linked to libR. Just reinstalling Rcpp from
| source solved the problem.

That makes sense, and thank you for closing the loop by reporting back.  If
you have a small self-contained example of rpy2 and Rcpp, can you send it my
way?  It may make sense to add this to the Rcpp_FAQ vignette.

Dirk
 
| Regards,
| Jonas
| 
| On Fri, Aug 12, 2011 at 3:16 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
| 
| 
|     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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| 
|     --
|     Two new Rcpp master classes for R and C++ integration scheduled for
|     New York (Sep 24) and San Francisco (Oct 8), more details are at
|     http://dirk.eddelbuettel.com/blog/2011/08/04#
|     rcpp_classes_2011-09_and_2011-10
|     http://www.revolutionanalytics.com/products/training/public/
|     rcpp-master-class.php
| 
| 

-- 
Two new Rcpp master classes for R and C++ integration scheduled for 
New York (Sep 24) and San Francisco (Oct 8), more details are at
http://dirk.eddelbuettel.com/blog/2011/08/04#rcpp_classes_2011-09_and_2011-10
http://www.revolutionanalytics.com/products/training/public/rcpp-master-class.php