I would like to create an R package which uses some C code, which in turn uses MPI. At the moment I'm only interested in creating this package for UNIX-like systems. The way I envisage this working is for the R package to contain an R function which uses the system call to run the C code as a separate process (passing to the C code the location of a file of data). The C code can then do what it needs to do with the data, send its output to a file, and when it has finished R can read the output from the file.
My question is, is it possible to create an R package which contains C code which can then be called by an R function in that package using the system call? The obstacles seem to be (i) compiling this C code in the right way for it to be called by system, and (ii) giving the R function responsible for calling the C code (via system) the location of the executable. >From my understanding of the R extensions manual (i) can be solved using careful configure script and Makevars file (though I don't know the details), and (ii) would require me to provide an R script `src/install.libs.R’, which would need to copy the executable to the right place, and modify my R function which uses the system call so it knows where to look for the executable. The reason I’m interested in calling the C code in this peculiar way, rather than using the .C interface, for example, is that I’m worried about using MPI from within R. At least, my knowledge of both R and MPI is insufficient to be confident that calling MPI from within R will run smoothly. Also, this way I can debug the C program entirely on its own. I realise there is an R package, Rmpi, which provides a wrapper for most of the MPI functions, but since all my code will be in C, it seems less sensible to make use of this, though I may be wrong. Thank you for taking to the time to read this, and I very much appreciate any advice, (especially) even if it is to say that my proposed approach is entirely daft and I should do things completely differently. Also, if you know of any examples of packages which do what I’ve described above, I’d be very glad to know (it seems Sjava does something like this?). Best wishes, Rajen Shah ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
