[Rcpp-devel] trying installing RcppCNPy with -std=c++11 (or c++0x) and failed due to incompatible number of arguments

[Dirk Eddelbuettel]

On 19 February 2013 at 12:26, Gong-Yi Liao wrote:
| 
| I read the 'Limitation' part of RppCNPy package's document 
| (RcppCNPy-intro) and found:
| 
| "So until R switches to allowing -std=c++0x on CRAN packages, users will 
| need to rebuild both Rcpp and RcppCNPy with the switch enabled."
| 
| Does that means putting  '-std=c++11' in CXXFLAGS  while building 
| RcppCNPy will not work ? ( I have build Rcpp with -std=c++11 without any 
| problem)

Ouch. Forget about that one. You are quite right.  The full context is:

   \subsection{Integer support}

   Support for integer data types is conditional on use of the \code{-std=c++0x}
   compiler extension. Only the newer standard supports the \code{long long int}
   type needed to represent \code{int64} data on a 32-bit OS.  So until \R
   switches to allowing \code{-std=c++0x} on CRAN packages, users will need to
   rebuild both \pkg{Rcpp} and \pkg{RcppCNPy} with the switch enabled. As shown
   in the previous examples, integers also transparently convert to float types.

So you are caught between a rock and a hard place.  If the build currently
fails with -std=c++0x (or -std=c++11) you will need to debug it.  I believe
this worked at some point --- I did a few quick releases last summer but
removed integer support relatively early on.

As the paragraph states, NumPy uses 64bit ints, and we only get those
(portably) in R via long long int, which in turn requires the currently
unsupported (at CRAN) C++11 switch.
 
| The reason I need to have '-std=c++0x' (or c++11) is loading the integer 
| data in np.array, I have done some simple experiment:
| 
| === In Python ==
| In [1]: x = pylab.randn(100, 3)
| In [2]: y = pylab.poisson(lam=3.5, size=200]
| In [3]: numpy.save('test.npy', [x, y])
| 
| 
| == In R (RcppCNPy is build without '-std=c++0x' )====
|  > library(RcppCNPy)
|  > z <- load('test.npy')
| Error in npyLoad("test.npy") : littleEndian error
| 
| So, I thought that rebuilding RcppCNPy with '-std=c++0x' can help me to 
| read the integer data restored in a .npy file.
| 
| Is there any way to process the integer data restored in .npy file other 
| than
| ==== In Python =====
| In [1]: y = pylab.double(poission(lam=3.5, size=200)
| In [2]: numpy.save('test.npy', [x, y])
| 
| ?

I don't think so / I don't know.  I really needed float / double support, so
I made that work.  For the rest you are on your own.  If I get some time I
will take a look, but I can't promise anything.

If you are on a 64-bit OS you may get by with long int but this will not, I
fear, extend to 32-bit and is hence not something I can put into a CRAN
release.

Sorry!

Dirk

| 
| Gong.
| 
| 
| On 02/19/2013 11:57 AM, Dirk Eddelbuettel wrote:
| > On 19 February 2013 at 11:47, Gong-Yi Liao wrote:
| > | * installing *source* package ‘RcppCNPy’ ...
| > | ** package ‘RcppCNPy’ successfully unpacked and MD5 sums checked
| > | ** libs
| > | g++ -I/usr/share/R/include -DNDEBUG
| > | -I"/usr/local/lib/R/site-library/Rcpp/include" -fpic -std=c++11 -O2
| > | -pipe -g -c cnpy.cpp -o cnpy.o
| >
| > Please remove the -std=c++11 from your CXXFLAGS (or however it crept in).
| >
| > CRAN does not accept it, the package is maintained and supported as a CRAN
| > package.  If you need extensions (such as the C++11 support) you are
| > currently on your own.
| >
| > | It seems that this problem is caused by some function defined
| > | in"codecvt.h".
| > | Does anyone have encountered similar problem ?
| >
| > It may be a simple matter of include file order. I don't know.
| >
| > Dirk
| >
| 
| 
| -- 
| Gong-Yi Liao
| Department of Statistics
| University of Connecticut
| 

-- 
Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com