/*

Copyright (C) 1996, 1997 John W. Eaton

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 2, 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, write to the Free
Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.

*/

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

#include "base-lu.h"

template <class lu_type, class lu_elt_type, class p_type, class p_elt_type>
lu_type
base_lu <lu_type, lu_elt_type, p_type, p_elt_type> :: L (void) const
{
  octave_idx_type a_nr = a_fact.rows ();
  octave_idx_type a_nc = a_fact.cols ();
  octave_idx_type mn = (a_nr < a_nc ? a_nr : a_nc);

  lu_type l (a_nr, mn, lu_elt_type (0.0));

  for (octave_idx_type i = 0; i < a_nr; i++)
    {
      if (i < a_nc)
	l.xelem (i, i) = 1.0;

      for (octave_idx_type j = 0; j < (i < a_nc ? i : a_nc); j++)
	l.xelem (i, j) = a_fact.xelem (i, j);
    }

  return l;
}

template <class lu_type, class lu_elt_type, class p_type, class p_elt_type>
lu_type
base_lu <lu_type, lu_elt_type, p_type, p_elt_type> :: U (void) const
{
  octave_idx_type a_nr = a_fact.rows ();
  octave_idx_type a_nc = a_fact.cols ();
  octave_idx_type mn = (a_nr < a_nc ? a_nr : a_nc);

  lu_type u (mn, a_nc, lu_elt_type (0.0));

  for (octave_idx_type i = 0; i < mn; i++)
    {
      for (octave_idx_type j = i; j < a_nc; j++)
	u.xelem (i, j) = a_fact.xelem (i, j);
    }

  return u;
}

template <class lu_type, class lu_elt_type, class p_type, class p_elt_type>
p_type
base_lu <lu_type, lu_elt_type, p_type, p_elt_type> :: P (void) const
{
  octave_idx_type a_nr = a_fact.rows ();

  Array<octave_idx_type> pvt (a_nr);

  for (octave_idx_type i = 0; i < a_nr; i++)
    pvt.xelem (i) = i;

  for (octave_idx_type i = 0; i < ipvt.length(); i++)
    {
      octave_idx_type k = ipvt.xelem (i);

      if (k != i)
	{
	  octave_idx_type tmp = pvt.xelem (k);
	  pvt.xelem (k) = pvt.xelem (i);
	  pvt.xelem (i) = tmp;
	}
    }

  p_type p (a_nr, a_nr, p_elt_type (0.0));

  for (octave_idx_type i = 0; i < a_nr; i++)
    p.xelem (i, pvt.xelem (i)) = 1.0;

  return p;
}

/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/
