//                                  -*- C++ -*-
/*

Copyright (C) 1992, 1993, 1994, 1995 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, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#if !defined (octave_SVD_h)
#define octave_SVD_h 1

#if defined (__GNUG__)
#pragma interface
#endif

class ostream;

#include "dDiagMatrix.h"
#include "dMatrix.h"

class SVD
{
friend class Matrix;

public:

  enum type
    {
      std,
      economy,
    };

  SVD (void) { }


  SVD (const Matrix& a, type svd_type) { init (a, svd_type); }

  SVD (const Matrix& a, int& info, type svd_type)
    {
      info = init (a, svd_type);
    }

  SVD (const SVD& a)
    {
      sigma = a.sigma;
      left_sm = a.left_sm;
      right_sm = a.right_sm;
    }

  SVD& operator = (const SVD& a)
    {
      sigma = a.sigma;
      left_sm = a.left_sm;
      right_sm = a.right_sm;

      return *this;
    }

  DiagMatrix singular_values (void) const { return sigma; }

  Matrix left_singular_matrix (void) const { return left_sm; }

  Matrix right_singular_matrix (void) const { return right_sm; }

  friend ostream&  operator << (ostream& os, const SVD& a);

private:

  int init (const Matrix& a, type svd_type = std);

  DiagMatrix sigma;
  Matrix left_sm;
  Matrix right_sm;
};

#endif

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