/*

Copyright (C) 1994-2015 John W. Eaton
Copyright (C) 2008-2009 Jaroslav Hajek
Copyright (C) 2009 VZLU Prague

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/>.

*/

#if ! defined (octave_qr_h)
#define octave_qr_h 1

#include "octave-config.h"

#include "Array.h"

namespace octave
{
namespace math
{

template <typename T>
class
qr
{
public:

  typedef typename T::element_type ELT_T;
  typedef typename T::row_vector_type RV_T;
  typedef typename T::column_vector_type CV_T;

  enum type
  {
    std,
    raw,
    economy
  };

  qr (void) : q (), r () { }

  qr (const T& a, type qr_type = qr::std)
    : q (), r ()
  {
    init (a, qr_type);
  }

  qr (const T& q, const T& r);

  qr (const qr& a) : q (a.q), r (a.r) { }

  qr& operator = (const qr& a)
  {
    if (this != &a)
      {
        q = a.q;
        r = a.r;
      }

    return *this;
  }

  virtual ~qr (void) { }

  T Q (void) const { return q; }

  T R (void) const { return r; }

  type get_type (void) const;

  bool regular (void) const;

  void init (const T& a, type qr_type);

  void update (const CV_T& u, const CV_T& v);

  void update (const T& u, const T& v);

  void insert_col (const CV_T& u, octave_idx_type j);

  void insert_col (const T& u, const Array<octave_idx_type>& j);

  void delete_col (octave_idx_type j);

  void delete_col (const Array<octave_idx_type>& j);

  void insert_row (const RV_T& u, octave_idx_type j);

  void delete_row (octave_idx_type j);

  void shift_cols (octave_idx_type i, octave_idx_type j);

protected:

  T q;
  T r;

  void form (octave_idx_type n, T& afact, ELT_T *tau, type qr_type);
};

extern void warn_qrupdate_once (void);

}
}

#endif