/*

Copyright (C) 2016 John W. Eaton
Copyright (C) 2004-2015 David Bateman
Copyright (C) 1998-2004 Andy Adler

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_sparse_lu_h)
#define octave_sparse_lu_h 1

#include "MArray.h"
#include "dSparse.h"

// If the sparse matrix classes become templated on the element type
// (i.e., sparse_matrix<double>), then it might be best to make the
// template parameter of this class also be the element type instead
// of the matrix type.

template <typename lu_type>
class
sparse_lu
{
public:

  typedef typename lu_type::element_type lu_elt_type;

  sparse_lu (void)
    : Lfact (), Ufact (), Rfact (), cond (0), P (), Q () { }

  sparse_lu (const lu_type& a, const Matrix& piv_thres = Matrix (),
             bool scale = false);

  sparse_lu (const lu_type& a, const ColumnVector& Qinit,
             const Matrix& piv_thres, bool scale = false,
             bool FixedQ = false, double droptol = -1.0,
             bool milu = false, bool udiag = false);

  sparse_lu (const sparse_lu& a)
    : Lfact (a.Lfact), Ufact (a.Ufact), Rfact (), cond (a.cond),
      P (a.P), Q (a.Q)
  { }

  sparse_lu& operator = (const sparse_lu& a)
  {
    if (this != &a)
      {
        Lfact = a.Lfact;
        Ufact = a.Ufact;
        cond = a.cond;
        P = a.P;
        Q = a.Q;
      }

    return *this;
  }

  virtual ~sparse_lu (void) { }

  lu_type L (void) const { return Lfact; }

  lu_type U (void) const { return Ufact; }

  SparseMatrix R (void) const { return Rfact; }

  lu_type Y (void) const;

  SparseMatrix Pc (void) const;

  SparseMatrix Pr (void) const;

  ColumnVector Pc_vec (void) const;

  ColumnVector Pr_vec (void) const;

  PermMatrix Pc_mat (void) const;

  PermMatrix Pr_mat (void) const;

  const octave_idx_type * row_perm (void) const { return P.fortran_vec (); }

  const octave_idx_type * col_perm (void) const { return Q.fortran_vec (); }

  double rcond (void) const { return cond; }

protected:

  lu_type Lfact;
  lu_type Ufact;
  SparseMatrix Rfact;

  double cond;

  MArray<octave_idx_type> P;
  MArray<octave_idx_type> Q;
};

#endif