vector<size_t> FEM::computeBoundaryNodes(Triangulation& Omega, Boundary& bndry, Predicate validAt) {
vector<size_t> res;
for (auto const & edge : bndry)
if (validAt(Omega.getNode(edge[0]))) res.push_back(edge[0]);
return res;
}
vector<double> FEM::constructVector(Function u, Triangulation& Omega) {
vector<double> uVec(Omega.numbOfNodes());
for (size_t i = 0; i < uVec.size(); ++i)
uVec[i] = u(Omega.getNode(i));
return uVec;
}