[Rd] Initializing a large data structure to be accessed strictly within a shared C library

Duncan Murdoch murdoch.duncan at gmail.com
Wed Dec 28 02:09:37 CET 2011

On 11-12-27 5:58 PM, James Muller wrote:
> Dear R-devel members,
> The question:  Is it possible to initialize and later free a large data
> structure strictly within a shared C library, to be used by a function in
> the C library that I'll call from R--without ever having to pass data to
> and from R? This is analogous to C++ object initialization/use/destruction,
> but if possible I'd like to stay in C.

Yes, if you use malloc or Calloc you'll get memory that you can manage 
yourself.  See Writing R Extensions, section 6.1.2.

Duncan Murdoch

> The context: I'm implementing a particle swarm optimization of a
> 60-dimension nonlinear transform, where the transform is defined in a
> half-gigabyte dataset. By carefully initializing a C struct I can trim a
> large amount of work from the PSO iteration stage. This is, of course,
> straight forward if I implement the whole thing in a self-contained C
> program--however, I'd like R to handle the optimization routines, and my
> shared library to implement the value function.
> So: what do folks think?
> Cheers,
> James
> 	[[alternative HTML version deleted]]
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