From 5233c01a26329306c9f1d08c1a39733aee2cc518 Mon Sep 17 00:00:00 2001
From: Tim Blechmann <timblech@users.sourceforge.net>
Date: Tue, 21 Dec 2004 09:22:10 +0000
Subject: This commit was generated by cvs2svn to compensate for changes in
 r2423, which included commits to RCS files with non-trunk default branches.

svn path=/trunk/externals/tb/; revision=2424
---
 chaos/src/ode_base.cpp | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 chaos/src/ode_base.cpp

(limited to 'chaos/src/ode_base.cpp')

diff --git a/chaos/src/ode_base.cpp b/chaos/src/ode_base.cpp
new file mode 100644
index 0000000..cfedeee
--- /dev/null
+++ b/chaos/src/ode_base.cpp
@@ -0,0 +1,90 @@
+// 
+//  
+//  chaos~
+//  Copyright (C) 2004  Tim Blechmann
+//  
+//  This program 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 program 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.
+//  
+//  You should have received a copy of the GNU General Public License
+//  along with this program; see the file COPYING.  If not, write to
+//  the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+//  Boston, MA 02111-1307, USA.
+
+#include "ode_base.hpp"
+
+void ode_base::rk1()
+{
+	m_system (m_k[0], m_data);
+	for (int i = 0; i != m_num_eq; ++i)
+		m_data[i] += m_dt * m_k[0][i];
+}
+
+
+void ode_base::rk2()
+{
+	m_system (m_k[0], m_data);
+	for (int i = 0; i != m_num_eq; ++i)
+		m_k[0][i] = m_k[0][i] * 0.5 * m_dt + m_data[i];
+	
+	m_system (m_k[1], m_k[0]);
+	for (int i = 0; i != m_num_eq; ++i)
+		m_data[i] += m_dt * m_k[1][i];
+}
+
+
+void ode_base::rk4()
+{
+	m_system (m_k[0], m_data);
+	for (int i = 0; i != m_num_eq; ++i)
+	{
+		m_k[0][i] *= m_dt;
+		m_tmp[i] = m_data[i] + 0.5 * m_k[0][i];
+	}
+
+	m_system (m_k[1], m_tmp);
+	for (int i = 0; i != m_num_eq; ++i)
+	{
+		m_k[1][i] *= m_dt;
+		m_tmp[i] = m_data[i] + 0.5 * m_k[1][i];
+	}
+	
+	m_system (m_k[2], m_tmp);
+	for (int i = 0; i != m_num_eq; ++i)
+	{
+		m_k[2][i] *= m_dt;
+		m_tmp[i] = m_data[i] + m_k[2][i];
+	}
+
+	m_system (m_k[3], m_tmp);
+	for (int i = 0; i != m_num_eq; ++i)
+		m_k[3][i] *= m_dt;
+
+	for (int i = 0; i != m_num_eq; ++i)
+		m_data[i] += (m_k[0][i] + 2. * (m_k[1][i] + m_k[2][i]) + m_k[3][i]) 
+			/ 6.;
+}
+
+void ode_base::m_step()
+{
+	switch (m_method)
+	{
+	case 0:
+		rk1();
+		break;
+	case 1:
+		rk2();
+		break;
+	case 2:
+		rk3();
+		break;
+	}
+	
+}
-- 
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