Dear Jaekwang,
The role of the additional quadrature formula is to ensure that your
function is not evaluated at "superconvergent" points, which would lead to
an underestimation in the error associated with the finite element solution.
I have little knowledge of functional analysis, so apart fro
Jarkwang,
Quadrature points and support points only coincide in special cases. In
particular, this not true for Gauss quadrature of order fe_degree+1 and FE_Q
elements.
When computing errors, you often want to avoid superconvergence effects and
hence use a quadrature rule different from the on
Hi, all.
I have a question on how 'VectorTools::integrate_difference' works
const MappingQ mapping (degree);
VectorTools::integrate_difference (mapping,
dof_handler,solution,Solution(),
difference_per_cell,QGauss(degree+2),VectorTools::L2_norm
