boost::layout_tolerance — Determines when to terminate layout of a particular graph based on a given relative tolerance.
template<typename T = double>
struct layout_tolerance {
// construct/copy/destruct
layout_tolerance(const T & = T(0.001));
// public member functions
template<typename Graph>
bool operator()(T,
typename boost::graph_traits< Graph >::vertex_descriptor,
const Graph &, bool) ;
};