[R-sig-hpc] openmp C functions in R

[luke at stat.uiowa.edu]

You could check out how I handle this in the pnmath package at

http://www.stat.uiowa.edu/~luke/R/experimental/pnmath_0.0-3.tar.gz

luke

On Thu, 1 Apr 2010, Carl Boettiger wrote:

> Dear R-sig-hpc,
>
> I have a C function that uses openmp for parallelization on shared memory
> architecture.  I have a Makevars file in the src directory which specifies
> the the -fopenmp flag.  When I run R CMD SHLIB file.c to compile my file, it
> uses the openmp flag and doesn't give any warnings.  Yet when I call the
> function from R using the .C interface, it uses only one processor.  If I
> compile a stand-alone version of the C code, it runs in parallel on all
> available processors.  Is this the expected behavior?  What is the correct
> way to adapt already parallelized C code to be callable from R?
>
> Thanks very much for your help.
> Carl
>
>

-- 
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
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