org.apache.commons.math3.geometry.enclosing

Class WelzlEncloser<S extends Space,P extends Point<S>>

java.lang.Object

org.apache.commons.math3.geometry.enclosing.WelzlEncloser<S,P>

Type Parameters:

S - Space type.

P - Point type.

All Implemented Interfaces:

Encloser<S,P>

public class WelzlEncloser<S extends Space,P extends Point<S>>
extends Object
implements Encloser<S,P>

Class implementing Emo Welzl algorithm to find the smallest enclosing ball in linear time.

The class implements the algorithm described in paper Smallest Enclosing Disks (Balls and Ellipsoids) by Emo Welzl, Lecture Notes in Computer Science 555 (1991) 359-370. The pivoting improvement published in the paper Fast and Robust Smallest Enclosing Balls, by Bernd Gärtner and further modified in paper Efficient Computation of Smallest Enclosing Balls in Three Dimensions by Linus Källberg to avoid performing local copies of data have been included.

Since:

3.3

Constructor Summary

Constructors

Constructor and Description
WelzlEncloser(double tolerance, SupportBallGenerator<S,P> generator) Simple constructor.

Method Summary

Modifier and Type	Method and Description
EnclosingBall<S,P>	enclose(Iterable<P> points) Find a ball enclosing a list of points.
P	selectFarthest(Iterable<P> points, EnclosingBall<S,P> ball) Select the point farthest to the current ball.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WelzlEncloser

public WelzlEncloser(double tolerance,
                     SupportBallGenerator<S,P> generator)

Simple constructor.

Parameters:

tolerance - below which points are consider to be identical

generator - generator for balls on support

Method Detail

enclose

public EnclosingBall<S,P> enclose(Iterable<P> points)

Find a ball enclosing a list of points.

Specified by:

enclose in interface Encloser<S extends Space,P extends Point<S>>

Parameters:

points - points to enclose

Returns:

enclosing ball

selectFarthest

public P selectFarthest(Iterable<P> points,
                        EnclosingBall<S,P> ball)

Select the point farthest to the current ball.

Parameters:

points - points to be enclosed

ball - current ball

Returns:

farthest point