67 lines
2.1 KiB
C
67 lines
2.1 KiB
C
|
/**********************************************************************
|
||
|
|
*
|
||
|
|
* GEOS - Geometry Engine Open Source
|
||
|
|
* http://geos.osgeo.org
|
||
|
|
*
|
||
|
|
* Copyright (C) 2005-2006 Refractions Research Inc.
|
||
|
|
* Copyright (C) 2001-2002 Vivid Solutions Inc.
|
||
|
|
*
|
||
|
|
* This is free software; you can redistribute and/or modify it under
|
||
|
|
* the terms of the GNU Lesser General Public Licence as published
|
||
|
|
* by the Free Software Foundation.
|
||
|
|
* See the COPYING file for more information.
|
||
|
|
*
|
||
|
|
**********************************************************************
|
||
|
|
*
|
||
|
|
* Last port: algorithm/RobustDeterminant.java 1.15 (JTS-1.10)
|
||
|
|
*
|
||
|
|
**********************************************************************/
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
|
||
|
|
#include <geos/export.h>
|
||
|
|
|
||
|
|
namespace geos {
|
||
|
|
namespace algorithm { // geos::algorithm
|
||
|
|
|
||
|
|
/** \brief
|
||
|
|
* 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:
|
||
|
|
*
|
||
|
|
* <pre>
|
||
|
|
*************************************************************************
|
||
|
|
* 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
|
||
|
|
*
|
||
|
|
**************************************************************************
|
||
|
|
* Copyright (c) 1995 by INRIA Prisme Project
|
||
|
|
* BP 93 06902 Sophia Antipolis Cedex, France.
|
||
|
|
* All rights reserved
|
||
|
|
**********************************************************************
|
||
|
|
* </pre>
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
class GEOS_DLL RobustDeterminant {
|
||
|
|
public:
|
||
|
|
|
||
|
|
/** \brief
|
||
|
|
* Computes the sign of the determinant of the 2x2 matrix
|
||
|
|
* with the given entries, in a robust way.
|
||
|
|
*
|
||
|
|
* @return -1 if the determinant is negative,
|
||
|
|
* @return 1 if the determinant is positive,
|
||
|
|
* @return 0 if the determinant is 0.
|
||
|
|
*/
|
||
|
|
static int signOfDet2x2(double x1, double y1, double x2, double y2);
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace geos::algorithm
|
||
|
|
} // namespace geos
|
||
|
|
|