1 files changed, 90 insertions, 0 deletions
diff --git a/karbon/core/vglobal.cc b/karbon/core/vglobal.cc
new file mode 100644
index 00000000..b118e5e2
--- /dev/null
+++ b/karbon/core/vglobal.cc
@@ -0,0 +1,90 @@
+/* This file is part of the KDE project
+   Copyright (C) 2001, The Karbon Developers
+   Copyright (C) 2002, The Karbon Developers
+
+   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 <math.h>
+
+#include "vglobal.h"
+
+
+int
+VGlobal::binomialCoeff( unsigned n, unsigned k )
+{
+	return
+		static_cast<int>(
+			0.5 +
+			exp(
+				factorialLn( n ) -
+				factorialLn( k ) -
+				factorialLn( n - k ) ) );
+}
+
+double
+VGlobal::factorialLn( unsigned n )
+{
+	const unsigned cacheSize = 100;
+
+	// A static array is initalized to zero.
+	static double 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 );
+	}
+}
+
+double
+VGlobal::gammaLn( double x )
+{
+	static double coeff[ 6 ] =
+	{
+		76.18009172947146,
+		-86.50532032941677,
+		24.01409824083091,
+		-1.231739572450155,
+		0.1208650973866179e-2,
+		-0.5395239384953e-5
+	};
+
+	double y = x;
+
+	double tmp = x + 5.5;
+	tmp -= ( x + 0.5 ) * log( tmp );
+
+	double ser = 1.000000000190015;
+
+	for( int i = 0; i < 5; ++i )
+	{
+		ser += coeff[ i ] / ++y;
+	}
+
+	return -tmp + log( 2.5066282746310005 * ser / x );
+}
+