File indexing completed on 2024-05-12 16:30:46

 /* This file is part of the KDE project
    Copyright (C) 2002 Lennart Kudling <kudling@kde.org>
    Copyright (C) 2004 Laurent Montel <montel@kde.org>
    Copyright (C) 2005-2006 Thomas Zander <zander@kde.org>
    Copyright (C) 2006 Tim Beaulen <tbscope@gmail.com>
    Copyright (C) 2008 Jan Hambrecht <jaham@gmx.net>
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
 */
 
 #include "KarbonGlobal.h"
 #include <math.h>
 
 int KarbonGlobal::binomialCoeff(unsigned n, unsigned k)
 {
     return
         static_cast<int>(
             0.5 +
             exp(
                 factorialLn(n) -
                 factorialLn(k) -
                 factorialLn(n - k)));
 }
 
 qreal KarbonGlobal::factorialLn(unsigned n)
 {
     const unsigned cacheSize = 100;
 
     // A static array is initialized to zero.
     static qreal cache[ cacheSize ];
 
 
     if (n <= 1)
         return 0.0;
 
     if (n <= cacheSize - 1) {
         return cache[ n ]
                ? cache[ n ]
                : (cache[ n ] = gammaLn(n + 1.0));
     } else {
         return gammaLn(n + 1.0);
     }
 }
 
 qreal KarbonGlobal::gammaLn(qreal x)
 {
     static const qreal coeff[ 6 ] = {
         76.18009172947146,
         -86.50532032941677,
         24.01409824083091,
         -1.231739572450155,
         0.1208650973866179e-2,
         -0.5395239384953e-5
     };
 
     qreal y = x;
 
     qreal tmp = x + 5.5;
     tmp -= (x + 0.5) * log(tmp);
 
     qreal ser = 1.000000000190015;
 
     for (int i = 0; i < 5; ++i) {
         ser += coeff[ i ] / ++y;
     }
 
     return -tmp + log(2.5066282746310005 * ser / x);
 }
 
 qreal KarbonGlobal::scalarProduct(const QPointF &p1, const QPointF &p2)
 {
     return p1.x() * p2.x() + p1.y() * p2.y();
 }
 
 bool KarbonGlobal::pointsAreNear(const QPointF &p1, const QPointF &p2, qreal range)
 {
     return (p2.x() >= p1.x() - range && p2.x() <= p1.x() + range && p2.y() >= p1.y() - range && p2.y() <= p1.y() + range);
 }
 
 QPointF KarbonGlobal::crossProduct(const QPointF &v1, const QPointF &v2)
 {
     return QPointF(v1.x() * v2.y(), -v1.y()*v2.x());
 }