add grad-div residual

git-svn-id: https://svn.dealii.org/trunk@33090 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/include/deal.II/integrators/divergence.h b/deal.II/include/deal.II/integrators/divergence.h
index 79438a8fba8e21a1aceaccb2ae320eafa987ae03..4f35e8f3e14cf7c261f365cc6f24bac69b3d816e 100644 (file)
--- a/deal.II/include/deal.II/integrators/divergence.h
+++ b/deal.II/include/deal.II/integrators/divergence.h
@@ -519,6 +519,45 @@ namespace LocalIntegrators
         }
     }
 
+    /**
+     * The weak form of the grad-div residual
+     * @f[
+     *  \int_Z \nabla\!\cdot\!u \nabla\!\cdot\!v \,dx
+     * @f]
+     *
+     * @author Guido Kanschat
+     * @date 2014
+     */
+    template <int dim, typename number>
+    void grad_div_residual (
+      Vector<number> &result,
+      const FEValuesBase<dim> &fetest,
+      const VectorSlice<const std::vector<std::vector<Tensor<1,dim> > > > &input,
+      const double factor = 1.)
+    {
+      const unsigned int n_dofs = fetest.dofs_per_cell;
+
+      AssertDimension(fetest.get_fe().n_components(), dim);
+      AssertVectorVectorDimension(input, dim, fetest.n_quadrature_points);
+      
+      for (unsigned int k=0; k<fetest.n_quadrature_points; ++k)
+        {
+          const double dx = factor * fetest.JxW(k);
+          for (unsigned int i=0; i<n_dofs; ++i)
+           {
+             double dv = 0.;
+             double du = 0.;
+             for (unsigned int d=0; d<dim; ++d)
+               {
+                 dv += fetest.shape_grad_component(i,k,d)[d];
+                 du += input[d][k][d];
+               }
+             
+             result(i) += dx * du * dv;
+           }
+        }
+    }
+
     /**
      * The jump of the normal component
      * @f[