/**
 * * Ported from [Shewchuk](http://docs.ros.org/kinetic/api/asr_approx_mvbb/html/Predicates_8cpp_source.html)
 * * see also https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf
 *
 * * Adaptive exact 2d orientation test.
 *
 * * Robust.
 *
 * Return a positive value if the points pa, pb, and pc occur in
 * counterclockwise order; a negative value if they occur in clockwise order;
 * and zero if they are collinear.  The result is also a rough approximation of
 * twice the signed area of the triangle defined by the three points.
 *
 * The result returned is the determinant of a matrix. This determinant is
 * computed adaptively, in the sense that exact arithmetic is used only to the
 * degree it is needed to ensure that the returned value has the correct sign.
 * Hence, orient2d() is usually quite fast, but will run more slowly when the
 * input points are collinear or nearly so.
 */
declare function orient2d(A: number[], B: number[], C: number[]): number;
export { orient2d };