/**
* \brief Get the other vertex in the edge.
*/
inline graph_type::vertex_type
get_other_vertex(const graph_type::edge_type& edge,
const graph_type::vertex_type& vertex) {
return vertex.id() == edge.source().id()? edge.target() : edge.source();
}
/**
* \brief Given an edge compute the error associated with that edge
*/
double extract_l2_error(const graph_type::edge_type & edge) {
const double pred =
edge.source().data().factor.dot(edge.target().data().factor);
return (edge.data().obs - pred) * (edge.data().obs - pred);
} // end of extract_l2_error
