[Gambas-user] Gambas3 and Gnu scientific library

[wally]

Yes, few surprises in direction science are highly appreciated :)

I have compile problems with the new "extern"
At revision 3850.    OpenSuse 11.3


gambas3_svn/trunk/main/gbx/gbx_c_application.c:401: undefined reference to 
`EXTERN_get_symbol'
collect2: ld returned 1 exit status

wally

On Wednesday, May 18, 2011 17:33:31 Jussi Lahtinen wrote:
> Benoit keeps on amazing us!
> 
> Jussi
> P.S. I haven't test it yet...
> 
> On Wed, May 18, 2011 at 18:21, wally <wally at ...2037...> wrote:
> > Thanks a lot ! :)
> > wally
> > 
> > On Wednesday, May 18, 2011 17:07:09 Benoît Minisini wrote:
> > > > Hello  Jussi,
> > > > 
> > > > in C the stuff works pretty nice, so i agree to your suggestion 2.
> > > > 
> > > > Do all math stuff directly in Gambas is an option i should check.
> > > > 
> > > > I think i mentioned that i use Gambas3 and want to make
> > > > interpolations, derivatives and integrals from an integrarray.
> > > > The array contains ADC outputs from a CCD linear array sensor
> > 
> > measurment
> > 
> > > > wally
> > > > 
> > > > On Monday, May 16, 2011 17:46:51 Jussi Lahtinen wrote:
> > > > > Not very easy task...
> > > > > Here is interpolation example in C.
> > 
> > http://www.gnu.org/software/gsl/manual/html_node/Interpolation-Example-
> > 
> > > > > pr og rams.html
> > > > > 
> > > > > As you can see, you need to call several functions to get what you
> > > > > want. Declaring those in Gambas is OK, except determining
> > > > > interpolation type!
> > > > > 
> > > > > You can find definition of interpolation type from "gsl_interp.h",
> > > > > and unfortunately it is not anything simple;
> > > > > 
> > > > > typedef struct {
> > > > > 
> > > > >   const char * name;
> > > > >   unsigned int min_size;
> > > > >   void *  (*alloc) (size_t size);
> > > > >   int     (*init)    (void *, const double xa[], const double ya[],
> > > > >   size_t
> > > > > 
> > > > > size);
> > > > > 
> > > > >   int     (*eval)    (const void *, const double xa[], const double
> > > > >   ya[],
> > > > > 
> > > > > size_t size, double x, gsl_interp_accel *, double * y);
> > > > > 
> > > > >   int     (*eval_deriv)  (const void *, const double xa[], const
> > 
> > double
> > 
> > > > > ya[], size_t size, double x, gsl_interp_accel *, double * y_p);
> > > > > 
> > > > >   int     (*eval_deriv2) (const void *, const double xa[], const
> > 
> > double
> > 
> > > > > ya[], size_t size, double x, gsl_interp_accel *, double * y_pp);
> > > > > 
> > > > >   int     (*eval_integ)  (const void *, const double xa[], const
> > 
> > double
> > 
> > > > > ya[], size_t size, gsl_interp_accel *, double a, double b, double *
> > > > > result); void    (*free)         (void *);
> > > > > 
> > > > > } gsl_interp_type;
> > > > > 
> > > > > GSL_VAR const gsl_interp_type * gsl_interp_cspline; * <-- this is
> > 
> > used
> > 
> > > > > in example*
> > > > > 
> > > > > 
> > > > > Right now I don't know how to implement that reasonably in Gambas.
> > > > > There are at least three possibilities to overcome this problem:
> > > > > 
> > > > > 1. Hope that Benoit will implement new feature to use external
> > > > > structures. 2. Use C to write your own interface between GSL and
> > > > > Gambas. Perhaps easiest option.
> > > > > 3. Do not use GSL at all, and write what you need purely with
> > > > > Gambas.
> > > > > 
> > > > > That's all I can say...
> > > > > Also because you didn't specify what you need exactly, nor are you
> > > > > using Gambas 2 or 3.
> > > > > 
> > > > > Jussi
> > > 
> > > Hi,
> > > 
> > > I added a System.GetExternSymbol() method in the last revision so that
> > 
> > you
> > 
> > > can get the address of the interpolation type structure.
> > > 
> > > You have to do something like that:
> > >       Dim gsl_interp_cspline As Pointer
> > >       
> > >       gsl_interp_cspline = Pointer@(System.GetExternSymbol("libgsl",
> > >       
> > >               "gsl_interp_cspline"))
> > > 
> > > Maybe the Pointer@() is not needed, I don't know. The symbol can be
> > > directly the address of the structure (no Pointer@ needed), or a
> > > pointer to the address of the structure.
> > > 
> > > Try and tell me.
> > > 
> > > Regards,
> > 
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