linfty.hh

// Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena 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, version 2 of the License.
//
// Olena 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 Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to produce
// an executable, this file does not by itself cause the resulting
// executable to be covered by the GNU General Public License.  This
// exception does not however invalidate any other reasons why the
// executable file might be covered by the GNU General Public License.

#ifndef MLN_NORM_LINFTY_HH
# define MLN_NORM_LINFTY_HH


# include <mln/math/abs.hh>
# include <mln/algebra/vec.hh>


namespace mln
{

  namespace norm
  {

    template <unsigned n, typename C>
    C linfty(const C (&vec)[n]);

    template <unsigned n, typename C>
    C linfty(const algebra::vec<n,C>& vec);


    template <unsigned n, typename C>
    C linfty_distance(const C (&vec1)[n], const C (&vec2)[n]);

    template <unsigned n, typename C>
    C linfty_distance(const algebra::vec<n,C>& vec1,
                      const algebra::vec<n,C>& vec2);


# ifndef MLN_INCLUDE_ONLY

    namespace impl
    {

      template <unsigned n, typename C, typename V>
      inline
      C linfty_(const V& vec)
      {
        C m = 0;
        for (unsigned i = 0; i < n; ++i)
          {
            // Compute the maximal component absolute value of the
            // vector.
            C mc = mln::math::abs(vec[i]);
            if (mc > m)
              m = mc;
          }
        return m;
      }

      template <unsigned n, typename C, typename V>
      inline
      C linfty_distance_(const V& vec1, const V& vec2)
      {
        C d = 0;
        for (unsigned i = 0; i < n; ++i)
          {
            // Compute the maximal absolute value of the distance
            // between components of the same index.
            C dc = mln::math::abs(vec1[i] - vec2[i]);
            if (dc > d)
              d = dc;
          }
        return d;
      }

    } // end of namespace mln::norm::impl


    /*----------.
    | Facades.  |
    `----------*/

    template <unsigned n, typename C>
    inline
    C linfty(const C (&vec)[n])
    {
      return impl::linfty_<n, C>(vec);
    }

    template <unsigned n, typename C>
    inline
    C linfty(const algebra::vec<n,C>& vec)
    {
      return impl::linfty_<n, C>(vec);
    }

    template <unsigned n, typename C>
    inline
    C linfty_distance(const C (&vec1)[n], const C (&vec2)[n])
    {
      return impl::linfty_distance_<n, C>(vec1, vec2);
    }

    template <unsigned n, typename C>
    inline
    C linfty_distance(const algebra::vec<n,C>& vec1,
                      const algebra::vec<n,C>& vec2)
    {
      return impl::linfty_distance_<n, C>(vec1, vec2);
    }

# endif // ! MLN_INCLUDE_ONLY

  } // end of namespace mln::norm

} // end of namespace mln


#endif // ! MLN_NORM_LINFTY_HH