[Gambas-user] Gambas3 and Gnu scientific library

[wally]

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-prog
> 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
> 
> On Mon, May 16, 2011 at 09:32, wally <wally at ...2037...> wrote:
> > Hello,
> > 
> > i need to process an integerarray using GSL (Gnu Scientific Library)
> > but i do not know how to do it. Does anybody have a code example
> > how to provide the array data to gsl and get back interpolation,
> > derivative and integral  data ?
> > 
> > wally
> > 
> > 
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