schur.h

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//
// Copyright (C) 1994-2026 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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// Octave is free software: you can redistribute it and/or modify it
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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"
 
OCTAVE_BEGIN_NAMESPACE(octave)
OCTAVE_BEGIN_NAMESPACE(math)
 
template <typename T>
class schur
{
public:
 
  schur () : 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 () = default;
 
  T schur_matrix () const { return m_schur_mat; }
 
  T unitary_schur_matrix () 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);
 
OCTAVE_END_NAMESPACE(math)
OCTAVE_END_NAMESPACE(octave)
 
#endif