Add the Euler method.

1 files changed, 78 insertions, 0 deletions

diff --git a/src/vZ/Euler.hpp b/src/vZ/Euler.hpp
new file mode 100644
index 0000000..56c5678
--- /dev/null
+++ b/src/vZ/Euler.hpp
@@ -0,0 +1,78 @@
+/*************************************************************************
+ * Copyright (C) 2009-2010 Tavian Barnes <tavianator@gmail.com>          *
+ *                                                                       *
+ * This file is part of The vZ Library.                                  *
+ *                                                                       *
+ * The vZ Library is free software; you can redistribute it and/or       *
+ * modify it under the terms of the GNU Lesser General Public License as *
+ * published by the Free Software Foundation; either version 3 of the    *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The vZ 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     *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#ifndef VZ_EULER_HPP
+#define VZ_EULER_HPP
+
+namespace vZ
+{
+  // Euler method
+  //
+  // Simplest Runge-Kutta method
+  // First order
+  // Its tableau is:
+  //
+  //   0|
+  //   -+-
+  //    |1
+  //
+  // y[n + 1] = y[n] + dt*f(y[n])
+  template <typename Y>
+  class GenericEulerIntegrator : public GenericSimpleIntegrator<Y>
+  {
+  public:
+    typedef typename GenericSimpleIntegrator<Y>::Scalar   Scalar;
+    typedef typename GenericSimpleIntegrator<Y>::Function Function;
+
+    GenericEulerIntegrator(Function f)
+      : GenericSimpleIntegrator<Y>(f, s_a, s_b) { }
+    ~GenericEulerIntegrator() { }
+
+  private:
+    typedef typename GenericSimpleIntegrator<Y>::ACoefficients ACoefficients;
+    typedef typename GenericSimpleIntegrator<Y>::BCoefficients BCoefficients;
+
+    static ACoefficients s_a;
+    static BCoefficients s_b;
+
+    static Scalar s_bArr[1];
+  };
+
+  // Type alias
+  typedef GenericEulerIntegrator<double> EulerIntegrator;
+
+  // Implementation
+
+  template <typename Y>
+  typename GenericEulerIntegrator<Y>::Scalar
+  GenericEulerIntegrator<Y>::s_bArr[1] = {
+    Scalar(1)
+  };
+
+  template <typename Y>
+  typename GenericEulerIntegrator<Y>::ACoefficients
+  GenericEulerIntegrator<Y>::s_a;
+
+  template <typename Y>
+  typename GenericEulerIntegrator<Y>::BCoefficients
+  GenericEulerIntegrator<Y>::s_b(s_bArr, s_bArr + 1);
+}
+
+#endif // VZ_EULER_HPP