closest_point.hh

// Copyright (C) 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_FUN_X2P_CLOSEST_POINT_HH
# define MLN_FUN_X2P_CLOSEST_POINT_HH

# include <mln/algebra/vec.hh>
# include <mln/norm/l2.hh>
# include <mln/core/site_set/p_array.hh>
# include <mln/core/site_set/box.hh>

namespace mln
{

  namespace fun
  {

    namespace x2p
    {

      template <typename P>
      struct closest_point
      {
        typedef algebra::vec<P::dim, float> input;
        typedef P result;

        closest_point(const p_array<P>& X, const box<P>& box)
          : box_(box), X(X)
          , log_functor_call(0)

        { }

        result
        //inline
        operator () (const input& Ck) const
        {
          ++log_functor_call;

          algebra::vec<P::dim,float> Cki = Ck;
          algebra::vec<P::dim,float> best_x = convert::to< algebra::vec<P::dim,float> >(X[0]);
          float best_d = norm::l2(Cki - best_x);
          for (unsigned j = 1; j < X.nsites(); ++j)
            {
              algebra::vec<P::dim,float> Xj = convert::to< algebra::vec<P::dim,float> >(X[j]);
              float d = norm::l2(Cki - Xj);
              if (d < best_d)
                {
                  best_d = d;
                  best_x = Xj;
                }
            }
          return convert::to<P>(best_x);
        }

        const box<P>& domain() const
        {
          return box_;
        }

        const box<P> box_;
        const p_array<P>& X;

        // log call to the functor
        mutable unsigned log_functor_call;
      };

    } // end of namespace mln::fun::x2p

  } // end of namespace mln::fun

} // end of namespace mln

#endif // ! MLN_FUN_X2P_CLOSEST_POINT_HH