Filtered_kernel_adaptor<CK>is a kernel that uses the filtering technique [BBP01] to obtain a kernel with exact and efficient predicate functors. The geometric constructions are exactly those of the kernel CK, which means that they are not necessarily exact.
In contrast to Filtered_kernel, the global functions are those of CK.
The following example shows how to produce a kernel whose geometric objects and constructions are those of Simple_cartesian<double> The predicate functors of the kernel are exact, the global functions are not.
#include <CGAL/Simple_cartesian.h> #include <CGAL/Filtered_kernel.h> typedef CGAL::Simple_cartesian<double> CK; typedef CGAL::Filtered_kernel_adaptor<CK> K; typedef K::Point_2 p(0,0), q(1,1), r(1,5); CGAL::orientation(p,q,r); // not exact typedef K::Orientation_2 orientation; orientation(p,q,r); // exact