RE: Problem with a dynamically linked function

[alejandro zamora soto]

Dear Carlo,
thank you for you answer,
you are right, with your modification everything works.
I was wondering if you know where the standard function in the octave source tree used  to override this problem is.
I guess one should always do this conversion of vectors at the beginning of the programs,
Cheers
Alex



> Subject: Re: Problem with a dynamically linked function
> From: address@hidden
> Date: Thu, 5 May 2011 21:09:28 +0200
> CC: address@hidden
> To: address@hidden
>
>
> On 5 May 2011, at 16:31, alejandro zamora soto wrote:
>
> > Dear all,
> >
> > I wrote a program with Octave and now I want to rewrite my functions in C++.
> >
> > First of all, I'm trying to use C++ to write a linked extension for Octave of a toy program that permutes the indices
> > of a tensor, in Octave:
> >
> > function gamp=mi_funcion(gam,perm_index)
> > gamp=permute(gam, perm_index);
> > end
> >
> > Then if i write this:
> >
> >
> > #include <octave/oct.h>
> > #include <iostream>
> >
> > DEFUN_DLD(mi_funcion, args, ,
> > "Return b = permute(a,perm_index).")
> > {
> > const MArray<int> perm_index=args(1).array_value();
> > MArray<double> a(args(0).array_value());
> >
> > // std::cout << perm_index << std::endl;
> >
> >
> > MArray<double> b( a.permute(perm_index));
> > return octave_value(b);
> > }
> >
> > I don't have problems during the compilation with "mkoctfile",
> > But I have problems when I use this function:
> >
> > "error: mi_funcion: permute: permutation vector contains an invalid element"
> >
> > could you help me to solve this problem?
> >
> >
> > Kind regards,
> >
> > Alex Zamora
>
> How did you call the function from within Octave?
>
> If you tried to use it the same way as 'permute' I guess your problem is with indexing.
> While the interpreter uses 1-based indexing the C++ uses 0-based indexing,
> the following works for me:
>
> --------------------------------------------------------
> #include <octave/oct.h>
>
> DEFUN_DLD(mi_funcion, args, ,
> "Return b = permute(a,perm_index).")
> {
>
> Array<octave_idx_type> perm_index=args(1).array_value ();
> for (octave_idx_type ii = 0; ii < perm_index.numel (); ii++)
> perm_index (ii) = perm_index (ii) - 1;
> Array<double> a=args(0).array_value ();
>
>
> Array<double> b = a.permute (perm_index);
> return octave_value (b);
>
> }
> --------------------------------------------------------
>
> >> a = reshape (1:16, [4 2 2]);
> >> b = mi_funcion (a, [3 1 2]);
> >> c = permute (a, [3 1 2]);
> >> size (b)
> ans =
>
> 2 4 2
>
> >> size (c)
> ans =
>
> 2 4 2
>
> >> size (a)
> ans =
>
> 4 2 2
>
> >>
> --------------------------------------------------------
>
> c.
>
>
>