// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set ts=4 sw=2 et sts=2:
#ifndef DUNE_HIERARCHICAL_SIMPLEX_P2_LOCALINTERPOLATION_HH
#define DUNE_HIERARCHICAL_SIMPLEX_P2_LOCALINTERPOLATION_HH

#include <vector>

namespace Dune 
{
    /**
       \tparam LB The LocalBasis implementation
    */
  template<class LB>
  class HierarchicalSimplexP2LocalInterpolation 
  {
  public:

    template<typename F, typename C>
    void interpolate (const F& f, std::vector<C>& out) const
    {
      typename LB::Traits::DomainType x;
      typename LB::Traits::RangeType y;

      dune_static_assert(LB::Traits::dimDomain <=3, "LocalInterpolation for HierarchicalSimplexP2 finite elements"
          " is only implemented for dimDomain <=3!");

      switch ( int(LB::Traits::dimDomain))  {

        case 1:

          out.resize(3);

          // First: the two vertex dofs
          x[0] = 0.0;   f.evaluate(x, y);    out[0] = y;
          x[0] = 1.0;   f.evaluate(x, y);    out[2] = y;

          // Then: the edge dof
          x[0] = 0.5;   f.evaluate(x, y);
          out[1] = y - 0.5*(out[0] + out[2]);

          break;


        case 2:

          out.resize(6);

          // First: the three vertex dofs
          x[0] = 0.0;    x[1] = 0.0;      f.evaluate(x, y);    out[0] = y;
          x[0] = 1.0;    x[1] = 0.0;      f.evaluate(x, y);    out[2] = y;
          x[0] = 0.0;    x[1] = 1.0;      f.evaluate(x, y);    out[5] = y;

          // Then: the three edge dofs
          x[0] = 0.5;    x[1] = 0.0;      f.evaluate(x, y);
          out[1] = y - 0.5*(out[0] + out[2]);

          x[0] = 0.0;    x[1] = 0.5;      f.evaluate(x, y);
          out[3] = y - 0.5*(out[0] + out[5]);

          x[0] = 0.5;    x[1] = 0.5;      f.evaluate(x, y);
          out[4] = y - 0.5*(out[2] + out[5]);

          break;

        case 3:

          out.resize(10);

          // First: the four vertex dofs
          x[0] = 0.0;    x[1] = 0.0;     x[2] = 0.0;    f.evaluate(x, y);    out[0] = y;
          x[0] = 1.0;    x[1] = 0.0;     x[2] = 0.0;    f.evaluate(x, y);    out[2] = y;
          x[0] = 0.0;    x[1] = 1.0;     x[2] = 0.0;    f.evaluate(x, y);    out[5] = y;
          x[0] = 0.0;    x[1] = 0.0;     x[2] = 1.0;    f.evaluate(x, y);    out[9] = y;

          // Then: the six edge dofs
          x[0] = 0.5;    x[1] = 0.0;     x[2] = 0.0;    f.evaluate(x, y);
          out[1] = y - 0.5*(out[0] + out[2]);

          x[0] = 0.0;    x[1] = 0.5;     x[2] = 0.0;    f.evaluate(x, y);
          out[3] = y - 0.5*(out[0] + out[5]);

          x[0] = 0.5;    x[1] = 0.5;     x[2] = 0.0;    f.evaluate(x, y);
          out[4] = y - 0.5*(out[2] + out[5]);

          x[0] = 0.0;    x[1] = 0.0;     x[2] = 0.5;    f.evaluate(x, y);
          out[6] = y - 0.5*(out[0] + out[9]);

          x[0] = 0.5;    x[1] = 0.0;     x[2] = 0.5;    f.evaluate(x, y);
          out[7] = y - 0.5*(out[2] + out[9]);

          x[0] = 0.0;    x[1] = 0.5;     x[2] = 0.5;    f.evaluate(x, y);
          out[8] = y - 0.5*(out[5] + out[9]);

          break;

      }
    }

  };
}

#endif
