Finite Element Assembly Using an Embedded Domain Specific Language

Listing 16

Pressure Poisson problem for Chorin’s method.

(  // The pressure field, using the default first order shape function

()  FieldVariable<1, ScalarField> p("Pressure", pressure_lss->solution_tag());

()  // The linear system manager

()  Handle<LSSActionUnsteady> pressure_lss = create_component<LSSActionUnsteady>("PressureLSS");

()  // The assembly action

()  Handle<ProtoAction> pressure_mat_assembly =

()  pressure_lss->create_component<ProtoAction>("MatrixAssembly");

()  pressure_mat_assembly->set_expression(elements_expression(LagrangeP1(),

()  group

() (

() _A(p) = _0,

() element_quadrature(_A(p) += transpose(nabla(p))*nabla(p)),

() pressure_lss->system_matrix += _A

() )));

()  

() Handle<ProtoAction> pressure_rhs_assembly =

() pressure_lss->create_component<ProtoAction>("RHSAssembly");

() pressure_rhs_assembly->set_expression(elements_expression(LagrangeP1P2(),

() group

() (

() _a[p] = _0,

() element_quadrature(_a[p] += transpose(N(p))*divergence(u)),

() pressure_lss->system_rhs += −lit(pressure_lss->invdt())*_a

() )));