fem_l2_norm.m

function res = fem_l2_norm(df)
%function res = fem_l2_norm(df)
%
% function computing the l2-norm of a discrete fem function

ressqr = df.dofs(:)' * ...
         df.df_info.l2_inner_product_matrix * ...
         df.dofs(:);
if ressqr < 0
  ressqr = 0;
end;
res = sqrt(ressqr);