////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1995-2021 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.
//
// 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.
//
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// 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.
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// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
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////////////////////////////////////////////////////////////////////////

#if ! defined (octave_base_min_h)
#define octave_base_min_h 1

#include "octave-config.h"

#include "dColVector.h"

class
base_minimizer
{
public:

  base_minimizer (void) : x () { }

  base_minimizer (const ColumnVector& xx) : x (xx) { }

  base_minimizer (const base_minimizer& a) : x (a.x) { }

  virtual ~base_minimizer (void) = default;

  base_minimizer& operator = (const base_minimizer& a)
  {
    if (this != &a)
      x = a.x;

    return *this;
  }

  // Derived classes must provide a function to actually do the minimization.

  virtual ColumnVector do_minimize (double& objf, octave_idx_type& inform,
                                    ColumnVector& lambda) = 0;

  // Lots of ways to call the single function and optionally set and get
  // additional information.

  virtual ColumnVector minimize (void)
  {
    double objf;
    octave_idx_type inform;
    ColumnVector lambda;
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (double& objf)
  {
    octave_idx_type inform;
    ColumnVector lambda;
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (double& objf, octave_idx_type& inform)
  {
    ColumnVector lambda;
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (double& objf, octave_idx_type& inform,
                                 ColumnVector& lambda)
  {
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (const ColumnVector& x0)
  {
    x = x0;
    double objf;
    octave_idx_type inform;
    ColumnVector lambda;
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (const ColumnVector& x0, double& objf)
  {
    x = x0;
    octave_idx_type inform;
    ColumnVector lambda;
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (const ColumnVector& x0, double& objf,
                                 octave_idx_type& inform)
  {
    x = x0;
    ColumnVector lambda;
    return do_minimize (objf, inform, lambda);
  }

  virtual ColumnVector minimize (const ColumnVector& x0, double& objf,
                                 octave_idx_type& inform, ColumnVector& lambda)
  {
    x = x0;
    return do_minimize (objf, inform, lambda);
  }

  octave_idx_type size (void) const { return x.numel (); }

protected:

  ColumnVector x;
};

#endif
