From murdoch.duncan at gmail.com  Wed Dec 28 02:09:37 2011
From: murdoch.duncan at gmail.com (Duncan Murdoch)
Date: Tue, 27 Dec 2011 20:09:37 -0500
Subject: [Rd] Initializing a large data structure to be accessed
 strictly within a shared C library
In-Reply-To: <CAChCbnoC9PQUPAxLe-Fi6gHG8AN+csz8AVJhw5g6PsO60fg=gg@mail.gmail.com>
References: <CAChCbnoC9PQUPAxLe-Fi6gHG8AN+csz8AVJhw5g6PsO60fg=gg@mail.gmail.com>
Message-ID: <4EFA6C51.5010300@gmail.com>

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