Re: Help linking to Octave (mathematical) functions

[Jerry <lanceboyle@qwest.net>]

On Monday, December 29, 2014 2:21:09 AM UTC-7, Stephen Leake wrote:
> Jerry writes:
> 
> >> Despite the documentation said it is like "shared library or shared 
> >> object", it is referring to Octave itself "An oct-file is a dynamical 
> >> extension of the Octave interpreter".
> >> On MacOS, even with GNAT, at the end, all object files are loaded by ld 
> >> but I haven't seen that oct files are supported by ld.
> >
> > That's not good. I wonder if the internal structure of an oct file is
> > similar to other files known by ld. I suppose this is a question for
> > the Octave developer list.
> 
> Yes. Or a Mac list; the problem seems to be with the "bundle" stuff.

Yes. I hope to get back to this soon, one way or another.
> 
> Can you try this on a Linux distribution?

Not easily. I don't have Linux installed on my Mac. But I see what you're getting at--the bundle stuff might be a Mac anomaly; I've seen MH_BUNDLE discussed on other lists but mostly it goes over my head.
> 
> 
> Since this is all open source, you could try compiling the bessel
> library from source using GNAT, and either creating a more standard
> library or just include it in your main project.

I hadn't thought of that. Seems reasonable and obvious now that you mention it. OTOH the Numerical Recipes book has a very quick solution based on Abramowitz & Stegun.
> 
> 
> Another option is to link the Octave interpreter to the Ada program, and
> then tell it to load the oct-file.
> 
> There may be an Octave library that lets you do this, hopefully with an
> Ada binding available.

Not sure how that would proceed. But for an earlier case where I needed a bit of Octave in an Ada program I did a hilariously crude thing: I had the Ada program write out the Octave source script to a text file then called Octave with pragma Import(C, system) (not sure why I didn't use GNAT.OS_Lib.Spawn), had Octave write out the answer to a new text file, and read that text file with the Ada program. A tad slow I would surmise but I then needed only one call to Octave.

Jerry
> 
> -- 
> -- Stephe