public static edge make_edge(point u, point v)
{
edge e;
e = GlobalMembersMemory.get_edge();
e.onext = e.oprev = e.dnext = e.dprev = e;
e.org = u;
e.dest = v;
if (u.entry_pt == null)
{
u.entry_pt = e;
}
if (v.entry_pt == null)
{
v.entry_pt = e;
}
return e;
}