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//
// Copyright (C) 1994-2022 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
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// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
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////////////////////////////////////////////////////////////////////////

#if ! defined (octave_schur_h)
#define octave_schur_h 1

#include "octave-config.h"

#include <string>

// FIXME: Don't really need these for compiling schur.h, but it messes
// up compilation in liboctave/array if these are not present.
#include "CMatrix.h"
#include "dMatrix.h"
#include "fCMatrix.h"
#include "fMatrix.h"

namespace octave
{
  namespace math
  {
    template <typename T>
    class
    schur
    {
    public:

      schur (void) : m_schur_mat (), m_unitary_schur_mat () { }

      schur (const T& a, const std::string& ord, bool calc_unitary = true)
        : m_schur_mat (), m_unitary_schur_mat ()
      {
        init (a, ord, calc_unitary);
      }

      schur (const T& a, const std::string& ord, octave_f77_int_type& info,
             bool calc_unitary = true)
        : m_schur_mat (), m_unitary_schur_mat ()
      {
        info = init (a, ord, calc_unitary);
      }

      // This one should really be protected or private but we need it in
      // rsf2csf and I don't see how to make that function a friend of
      // this class.
      schur (const T& s, const T& u) : m_schur_mat (s), m_unitary_schur_mat (u)
      { }

      schur (const schur& a)
        : m_schur_mat (a.m_schur_mat),
          m_unitary_schur_mat (a.m_unitary_schur_mat)
      { }

      schur& operator = (const schur& a)
      {
        if (this != &a)
          {
            m_schur_mat = a.m_schur_mat;
            m_unitary_schur_mat = a.m_unitary_schur_mat;
          }

        return *this;
      }

      ~schur (void) = default;

      T schur_matrix (void) const { return m_schur_mat; }

      T unitary_schur_matrix (void) const { return m_unitary_schur_mat; }

    protected:

    private:

      T m_schur_mat;
      T m_unitary_schur_mat;

      OCTAVE_API octave_f77_int_type
      init (const T& a, const std::string& ord, bool calc_unitary);
    };

    template <typename RT, typename AT>
    extern OCTAVE_API schur<RT>
    rsf2csf (const AT& s, const AT& u);
  }
}

#endif