pk2dlocalcoefficients.hh

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
 
#ifndef DUNE_PK2DLOCALCOEFFICIENTS_HH
#define DUNE_PK2DLOCALCOEFFICIENTS_HH
 
#include <cstddef>
#include <vector>
 
#include <dune/localfunctions/common/localkey.hh>
 
namespace Dune
{
 
  template<unsigned int k>
  class Pk2DLocalCoefficients
  {
    enum {N = (k+1)*(k+2)/2};
 
  public:
    Pk2DLocalCoefficients () : li(N)
    {
      fill_default();
    }
 
    Pk2DLocalCoefficients (int variant) : li(N)
    {
      fill_default();
      bool flip[3];
      for (int i = 0; i < 3; ++i)
        flip[i] = variant & (1<<i);
      for (int i=0; i<N; i++)
        if (li[i].codim()==1 && flip[li[i].subEntity()])
          li[i].index(k-2-li[i].index());
    }
 
    template<class VertexMap>
    explicit Pk2DLocalCoefficients(const VertexMap &vertexmap) : li(N)
    {
      fill_default();
      bool flip[3];
      flip[0] = vertexmap[0] > vertexmap[1];
      flip[1] = vertexmap[0] > vertexmap[2];
      flip[2] = vertexmap[1] > vertexmap[2];
      for (std::size_t i=0; i<N; i++)
        if (li[i].codim()==1 && flip[li[i].subEntity()])
          li[i].index(k-2-li[i].index());
    }
 
    std::size_t size () const
    {
      return N;
    }
 
    const LocalKey& localKey (std::size_t i) const
    {
      return li[i];
    }
 
  private:
    std::vector<LocalKey> li;
 
    void fill_default ()
    {
      if (k==0)
      {
        li[0] = LocalKey(0,0,0);
        return;
      }
      int n=0;
      int c=0;
      for (unsigned int j=0; j<=k; j++)
        for (unsigned int i=0; i<=k-j; i++)
        {
          if (i==0 && j==0)
          {
            li[n++] = LocalKey(0,2,0);
            continue;
          }
          if (i==k && j==0)
          {
            li[n++] = LocalKey(1,2,0);
            continue;
          }
          if (i==0 && j==k)
          {
            li[n++] = LocalKey(2,2,0);
            continue;
          }
          if (j==0)
          {
            li[n++] = LocalKey(0,1,i-1);
            continue;
          }
          if (i==0)
          {
            li[n++] = LocalKey(1,1,j-1);
            continue;
          }
          if (i+j==k)
          {
            li[n++] = LocalKey(2,1,j-1);
            continue;
          }
          li[n++] = LocalKey(0,0,c++);
        }
    }
  };
 
}
 
#endif