Finite Element Assembly Using an Embedded Domain Specific Language

Listing 11

Definition of the Coofluid 3 gradient operation, using a user-defined terminal.

(  // Operator definition

()  struct DivOp

()  {

()   // The result is a scalar

()   typedef Real result_type;

()  

()   // Return the divergence of unknown var, computed at mapped_coords

()   template<typename VarT>

()   Real operator()(const VarT& var, const typename VarT::MappedCoordsT& mapped_coords)

() {

()  // Get the gradient matrix

()  const typename VarT::GradientT& nabla = var.nabla(mapped_coords);

()  Real result = 0.;

()  // Apply each component and return the result

()  for(int i = 0; i != VarT::EtypeT::dimensionality; ++i)

()  {

()   result += nabla.row(i) * var.value().col(i);

()  }

()  return result;

() }

()  

() // Divergence at the current quadrature point

() template<typename VarT>

() Real operator()(const VarT& var);

() };

()  

() // The terminal to use in the language

() // divergence(v, xi): compute the divergence at any mapped coordinate xi

() // divergence(v): compute the divergence at current quadrature point

() static MakeSFOp<DivOp>::type const divergence = ;