## CGAL::Filtered_kernel_adaptor<CK>

### Definition

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.

### Is Model for the Concept

Kernel

#include <CGAL/Filtered_kernel.h>

### Example

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