/*

Copyright (C) 2007 David Bateman

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#include <iostream>
#include <fstream>
#include <cmath>
#include <string>

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "oct.h"

DEFUN_DLD (__dsearchn__, args, ,
	"-*- texinfo -*-\n\
@deftypefn {Loadable Function} {[@var{idx}, @var{d}] =} dsearch (@var{x}, @var{xi})\n\
Undocumented internal function.\n\
@end deftypefn")
{
  int nargin = args.length();
  octave_value_list retval;

  if (nargin != 2)
    {
      print_usage ();
      return retval;
    }

  Matrix x = args(0).matrix_value().transpose ();
  Matrix xi = args(1).matrix_value().transpose ();

  if (! error_state)
    {
      if (x.rows() != xi.rows() || x.columns() < 1)
	error ("__dsearch__: dimensional mismatch");
      else
	{
	  octave_idx_type n = x.rows();
	  octave_idx_type nx = x.columns();
	  octave_idx_type nxi = xi.columns();

	  ColumnVector idx (nxi);
	  double *pidx = idx.fortran_vec ();
	  ColumnVector dist (nxi);
	  double *pdist = dist.fortran_vec ();

#define DIST(dd, y, yi, m) \
  dd = 0.; \
  for (octave_idx_type k = 0; k < m; k++) \
   { \
     double yd = y[k] - yi[k]; \
     dd += yd * yd; \
   } \
  dd = sqrt (dd);

	  const double *pxi = xi.fortran_vec ();
	  for (octave_idx_type i = 0; i < nxi; i++)
	    {
	      double d0;
	      const double *px = x.fortran_vec ();
	      DIST(d0, px, pxi, n);
	      *pidx = 1.;
	      for (octave_idx_type j = 1; j < nx; j++)
		{
		  px += n;
		  double d;
		  DIST (d, px, pxi, n);
		  if (d < d0)
		    {
		      d0 = d;
		      *pidx = static_cast<double>(j + 1);
		    }
		  OCTAVE_QUIT;
 		}

	      *pdist++ = d0; 
	      pidx++;
	      pxi += n;
	    }

	  retval(1) = dist;
	  retval(0) = idx;
	}
    }

  return retval;
}
