Class RobustDeterminant

java.lang.Object

org.locationtech.jts.algorithm.RobustDeterminant

public class RobustDeterminant
extends Object

Implements an algorithm to compute the sign of a 2x2 determinant for double precision values robustly. It is a direct translation of code developed by Olivier Devillers.

The original code carries the following copyright notice:

Author : Olivier Devillers
Olivier.Devillers@sophia.inria.fr
http:/www.inria.fr:/prisme/personnel/devillers/anglais/determinant.html

Relicensed under EDL and EPL with Permission from Olivier Devillers




             Copyright (c) 1995  by  INRIA Prisme Project
                 BP 93 06902 Sophia Antipolis Cedex, France.
                          All rights reserved

Version:

1.7

Constructor Summary

Constructors

Constructor	Description
RobustDeterminant()

Method Summary

Modifier and Type	Method	Description
static int	orientationIndex(Coordinate p1, Coordinate p2, Coordinate q)	Returns the index of the direction of the point q relative to a vector specified by p1-p2.
static int	signOfDet2x2(double x1, double y1, double x2, double y2)	Computes the sign of the determinant of the 2x2 matrix with the given entries, in a robust way.

Methods inherited from class Object

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

Constructor Details

RobustDeterminant

public RobustDeterminant()

Method Details

signOfDet2x2

public static int signOfDet2x2(double x1,
 double y1,
 double x2,
 double y2)

Computes the sign of the determinant of the 2x2 matrix with the given entries, in a robust way.

Returns:

-1 if the determinant is negative,

orientationIndex

public static int orientationIndex(Coordinate p1,
 Coordinate p2,
 Coordinate q)

Returns the index of the direction of the point q relative to a vector specified by p1-p2.

Parameters:

p1 - the origin point of the vector

p2 - the final point of the vector

q - the point to compute the direction to

Returns:

1 if q is counter-clockwise (left) from p1-p2