From octave-maintainers-request at bevo dot che dot wisc dot edu  Fri Oct 22 14:22:13 1999
Subject: Contributing a kron function 
From: etienne grossmann <etienne at anonimo dot isr dot ist dot utl dot pt>
To: octave-maintainers at bevo dot che dot wisc dot edu, heberf@calvin.wustl.edu
CC: etienne at isr dot ist dot utl dot pt
Date: Fri, 22 Oct 1999 20:21:26 +0100 (WEST)



  Hello,

  let's say I were to contribute a builtin kron function, based on
Heber's code :

======================================================================
#include <octave/oct.h>
#include "config.h"
#include "oct-obj.h"
#include "oct-map.h"
#include "defun-dld.h"
#include "toplev.h"

DEFUN_DLD (newkron, args, ,"Faster Kronecker Product")
{

  octave_value_list retval;

  Matrix A = args(0).matrix_value();
  Matrix B = args(1).matrix_value();
  
  int ra = A.rows();
  int ca = A.columns();
  int rb = B.rows();
  int cb = B.columns();
  int r = ra*rb;
  int c = ca*cb;
  Matrix tmpmat(rb,cb,0);
  Matrix C(r,c,0);
  for (int i=0; i<ra; i++)
    {
      for (int j=0; j<ca; j++)
        {
          tmpmat = A(i,j)*B;
          C = C.insert(tmpmat,i*rb,j*cb);
        }
    }
  retval(0) = octave_value(C);
return retval;

}
======================================================================

  I guess I would have to add another function for 2 ComplexMatrix
arguments. Right? 

  And put it in a "src/DLD-FUNCTIONS/kron.cc"

  And add kron.cc to the definition of  DLD_XSRC in src/Makefile.in

  Does that sound correct? Is there a better place (e.g. in data.cc)
to define such a function?

  Other things that could be useful would include a little test suite,
I guess (any preferred format for that?).

  Heber, have you already done a all/some of the above?

  Cheers,

  Etienne