com.vividsolutions.jts.algorithm

Class 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
 
 Olivier Devillers has allowed the code to be distributed under
 the LGPL (2012-02-16) saying "It is ok for LGPL distribution."
 



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

    • Constructor Detail

      • RobustDeterminant

        public RobustDeterminant()

    • Method Detail

      • 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