#ifndef DUNE_RT0TRIANGLELOCALBASIS_HH
#define DUNE_RT0TRIANGLELOCALBASIS_HH

#include <dune/common/fmatrix.hh>

#include <dune/localfunctions/common/localbasis.hh>

namespace Dune 
{
  /**@ingroup LocalBasisImplementation
	 \brief Lowest order Raviart-Thomas shape functions on the reference triangle.

	 \tparam D Type to represent the field in the domain.
	 \tparam R Type to represent the field in the range.

	 \nosubgrouping
  */
  template<class D, class R>
  class RT02DLocalBasis
  {
  public:
	typedef LocalBasisTraits<D,2,Dune::FieldVector<D,2>,R,2,Dune::FieldVector<R,2>,
							   Dune::FieldMatrix<R,2,2> > Traits;

	//! \brief Standard constructor
	RT02DLocalBasis ()
	{
	  sign0 = sign1 = sign2 = 1.0;
	}

	//! \brief Make set numer s, where 0<=s<8
	RT02DLocalBasis (unsigned int s)
	{
	  sign0 = sign1 = sign2 = 1.0;
	  if (s&1) sign0 = -1.0;
	  if (s&2) sign1 = -1.0;
	  if (s&4) sign2 = -1.0;
	}

	//! \brief number of shape functions
	unsigned int size () const
	{
	  return 3;
	}

	//! \brief Evaluate all shape functions
	inline void evaluateFunction (const typename Traits::DomainType& in,
								  std::vector<typename Traits::RangeType>& out) const
	{ 
	  out.resize(3);
	  out[0][0] = sign0*in[0];       out[0][1]=sign0*(in[1]-1.0);
	  out[1][0] = sign1*(in[0]-1.0); out[1][1]=sign1*in[1];
	  out[2][0] = sign2*in[0];       out[2][1]=sign2*in[1];
	}

	//! \brief Evaluate Jacobian of all shape functions
	inline void 
	evaluateJacobian (const typename Traits::DomainType& in,         // position
					  std::vector<typename Traits::JacobianType>& out) const      // return value
	{  
	  out.resize(3);
	  out[0][0][0] = sign0;       out[0][0][1] = 0; 
	  out[0][1][0] = 0;           out[0][1][1] = sign0;
	  out[1][0][0] = sign1;       out[1][0][1] = 0; 
	  out[1][1][0] = 0;           out[1][1][1] = sign1;
	  out[2][0][0] = sign2;       out[2][0][1] = 0; 
	  out[2][1][0] = 0;           out[2][1][1] = sign2;
	}

	//! \brief Polynomial order of the shape functions
	unsigned int order () const
	{
	  return 1;
	}

  private:
	R sign0, sign1, sign2;
  };
}
#endif
