de.lmu.ifi.dbs.elki.math.geometry

Class SweepHullDelaunay2D.Triangle

java.lang.Object

de.lmu.ifi.dbs.elki.math.geometry.SweepHullDelaunay2D.Triangle

Enclosing class:

SweepHullDelaunay2D

public static class SweepHullDelaunay2D.Triangle
extends java.lang.Object

Class representing a triangle, by referencing points in a list.

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
int	a References to points in Delaunay2D.points
int	ab References to neighbor triangles
int	b References to points in Delaunay2D.points
int	bc References to neighbor triangles
int	c References to points in Delaunay2D.points
int	ca References to neighbor triangles
double[]	m Center double[]
double	r2 Circumcircle parameters

Constructor Summary

Constructors

Constructor and Description
Triangle(int x, int y, int z) Constructor.

Method Summary

Modifier and Type	Method and Description
(package private) void	copyFrom(SweepHullDelaunay2D.Triangle o) Copy the values from another triangle.
(package private) SweepHullDelaunay2D.Orientation	findOrientation(SweepHullDelaunay2D.Triangle oth) Find the orientation of the triangles to each other.
boolean	inCircle(double[] opp) Test whether a point is within the circumference circle.
(package private) boolean	isClockwise(java.util.List<double[]> points) Verify that the triangle is clockwise
(package private) void	makeClockwise(java.util.List<double[]> points) Make the triangle clockwise
(package private) void	replaceEdge(int a, int b, int ol, int ne) Replace an edge
(package private) void	set(int a, int ab, int b, int bc, int c, int ca) Update the triangle.
java.lang.String	toString()
private boolean	updateCircumcircle(java.util.List<double[]> points) Recompute the location and squared radius of circumcircle.

Methods inherited from class java.lang.Object

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

Field Detail

a

public int a

References to points in Delaunay2D.points

b

public int b

References to points in Delaunay2D.points

c

public int c

References to points in Delaunay2D.points

ab

public int ab

References to neighbor triangles

ca

public int ca

References to neighbor triangles

bc

public int bc

References to neighbor triangles

r2

public double r2

Circumcircle parameters

m

public double[] m

Center double[]

Constructor Detail

Triangle

public Triangle(int x,
                int y,
                int z)

Constructor.

Parameters:

x -

y -

z -

Method Detail

replaceEdge

void replaceEdge(int a,
                 int b,
                 int ol,
                 int ne)

Replace an edge

Parameters:

a - First point

b - Second point

ol - Previous value

ne - New value

set

void set(int a,
         int ab,
         int b,
         int bc,
         int c,
         int ca)

Update the triangle.

Parameters:

a - First point

ab - Edge

b - Second point

bc - Edge

c - Third point

ca - Edge

inCircle

public boolean inCircle(double[] opp)

Test whether a point is within the circumference circle.

Parameters:

opp - Test double[]

Returns:

true when contained

findOrientation

SweepHullDelaunay2D.Orientation findOrientation(SweepHullDelaunay2D.Triangle oth)

Find the orientation of the triangles to each other.

Parameters:

oth - Other triangle

Returns:

shared edge

makeClockwise

void makeClockwise(java.util.List<double[]> points)

Make the triangle clockwise

isClockwise

boolean isClockwise(java.util.List<double[]> points)

Verify that the triangle is clockwise

copyFrom

void copyFrom(SweepHullDelaunay2D.Triangle o)

Copy the values from another triangle.

Parameters:

o - object to copy from

updateCircumcircle

private boolean updateCircumcircle(java.util.List<double[]> points)

Recompute the location and squared radius of circumcircle.

Note: numerical stability is important; and this is not entirely robust to degenerate cases.

Careful: the midpoint of the circumcircle is not the average of the corners!

Returns:

success

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object