Release 0.61.08

[synfig.git] / ETL / tags / 0.61.06 / ETL / _calculus.h

diff --git a/ETL/tags/0.61.06/ETL/_calculus.h b/ETL/tags/0.61.06/ETL/_calculus.h
new file mode 100644 (file)
index 0000000..a9c95ed
--- /dev/null
+++ b/ETL/tags/0.61.06/ETL/_calculus.h
@@ -0,0 +1,89 @@
+/*! ========================================================================
+** Extended Template and Library
+** Calculus Functional Classes Implementation
+** $Id$
+**
+** Copyright (c) 2002 Robert B. Quattlebaum Jr.
+**
+** This package is free software; you can redistribute it and/or
+** modify it under the terms of the GNU General Public License as
+** published by the Free Software Foundation; either version 2 of
+** the License, or (at your option) any later version.
+**
+** This package 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
+** General Public License for more details.
+**
+** === N O T E S ===========================================================
+**
+** ========================================================================= */
+
+/* === S T A R T =========================================================== */
+
+#ifndef __ETL__CALCULUS_H
+#define __ETL__CALCULUS_H
+
+/* === H E A D E R S ======================================================= */
+
+#include <functional>
+
+/* === M A C R O S ========================================================= */
+
+//#ifndef _EPSILON
+//#define _EPSILON             0.0000001
+//#endif
+
+#define ETL_FIXED_DERIVATIVE 1
+
+/* === T Y P E D E F S ===================================================== */
+
+/* === C L A S S E S & S T R U C T S ======================================= */
+
+_ETL_BEGIN_NAMESPACE
+
+template <typename T>
+class derivative : public std::unary_function<typename T::argument_type,typename T::result_type>
+{
+       T func;
+       typename T::argument_type epsilon;
+public:
+       explicit derivative(const T &x, const typename T::argument_type &epsilon=0.000001):func(x),epsilon(epsilon) { }
+
+       typename T::result_type
+       operator()(const typename T::argument_type &x)const
+       {
+#ifdef ETL_FIXED_DERIVATIVE
+               return (func(x+epsilon)-func(x))/epsilon;
+#else
+               return (func(x)-func(x+epsilon))/epsilon;
+#endif
+       }
+};
+
+template <typename T>
+class integral : public std::binary_function<typename T::argument_type,typename T::argument_type,typename T::result_type>
+{
+       T func;
+       int samples;
+public:
+       explicit integral(const T &x, const int &samples=500):func(x),samples(samples) { }
+
+       typename T::result_type
+       operator()(typename T::argument_type x,typename T::argument_type y)const
+       {
+               typename T::result_type ret=0;
+               int i=samples;
+               const typename T::argument_type increment=(y-x)/i;
+
+               for(;i;i--,x+=increment)
+                       ret+=(func(x)+func(x+increment))*increment/2;
+               return ret;
+       }
+};
+
+_ETL_END_NAMESPACE
+
+/* === E N D =============================================================== */
+
+#endif