Class AklToussaintHeuristic
java.lang.Object
org.apache.commons.math3.geometry.euclidean.twod.hull.AklToussaintHeuristic
A simple heuristic to improve the performance of convex hull algorithms.
The heuristic is based on the idea of a convex quadrilateral, which is formed by four points with the lowest and highest x / y coordinates. Any point that lies inside this quadrilateral can not be part of the convex hull and can thus be safely discarded before generating the convex hull itself.
The complexity of the operation is O(n), and may greatly improve the time it takes to construct the convex hull afterwards, depending on the point distribution.
- Since:
- 3.3
- See Also:
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionbuildQuadrilateral
(Vector2D... points) Build the convex quadrilateral with the found corner points (with min/max x/y coordinates).private static boolean
insideQuadrilateral
(Vector2D point, List<Vector2D> quadrilateralPoints) Checks if the given point is located within the convex quadrilateral.static Collection
<Vector2D> reducePoints
(Collection<Vector2D> points) Returns a point set that is reduced by all points for which it is safe to assume that they are not part of the convex hull.
-
Constructor Details
-
AklToussaintHeuristic
private AklToussaintHeuristic()Hide utility constructor.
-
-
Method Details
-
reducePoints
Returns a point set that is reduced by all points for which it is safe to assume that they are not part of the convex hull.- Parameters:
points
- the original point set- Returns:
- a reduced point set, useful as input for convex hull algorithms
-
buildQuadrilateral
Build the convex quadrilateral with the found corner points (with min/max x/y coordinates).- Parameters:
points
- the respective points with min/max x/y coordinate- Returns:
- the quadrilateral
-
insideQuadrilateral
Checks if the given point is located within the convex quadrilateral.- Parameters:
point
- the point to checkquadrilateralPoints
- the convex quadrilateral, represented by 4 points- Returns:
true
if the point is inside the quadrilateral,false
otherwise
-