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diff --git a/chaos/src/driven_van_der_pol.hpp b/chaos/src/driven_van_der_pol.hpp
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+++ b/chaos/src/driven_van_der_pol.hpp
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+//
+//
+//  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"
+#include <cmath>
+
+//  driven van_der_pol:
+//      d2u/dt2 + a*(u*u -1)*du/dt + u = k * cos(Omega*t)
+//  equivalent:
+//      du1/dt = u2
+//      du2/dt = -a*(u1*u1 - 1)*u2 - u1 + k*cos(u3)
+//      du3/dt = Omega
+//  taken from Willi-Hans Steeb: Chaos and Fractals
+
+class driven_van_der_pol
+    : public ode_base<3>
+{
+public:
+    driven_van_der_pol()
+    {
+        CHAOS_PAR_INIT(method,2);
+        CHAOS_PAR_INIT(dt,0.01);
+
+        CHAOS_SYS_INIT(u1,0.8, 0);
+        CHAOS_SYS_INIT(u2,0.6, 1);
+        CHAOS_SYS_INIT(u3,0.4, 2);
+
+        CHAOS_PAR_INIT(a,5);
+        CHAOS_PAR_INIT(Omega,2.466);
+        CHAOS_PAR_INIT(k,5);
+    }
+
+
+
+    void m_system(data_t* deriv, data_t* data)
+    {
+        data_t u1 = data[0], u2 = data[1], u3 = data[2];
+
+        deriv[0] = u2;
+        deriv[1] = - CHAOS_PARAMETER(a) * (u1*u1 -1) * u2 - u1 +
+            CHAOS_PARAMETER(k)*cos(u3);
+        deriv[2] = CHAOS_PARAMETER(Omega);
+    }
+
+    void m_verify()
+    {
+        /* make sure to stay in the range of 2 pi */
+        if (m_data[2] > 2*M_PI)
+            m_data[2] = std::fmod(m_data[2], data_t(2*M_PI));
+    }
+
+    CHAOS_SYSVAR_FUNCS(u1, 0);
+    CHAOS_SYSVAR_FUNCS(u2, 1);
+    CHAOS_SYSVAR_FUNCS(u3, 2);
+
+    CHAOS_SYSPAR_FUNCS(a);
+    CHAOS_SYSPAR_FUNCS(k);
+    CHAOS_SYSPAR_FUNCS(Omega);
+};
+
+
+#define DRIVEN_VAN_DER_POL_CALLBACKS            \
+ODE_CALLBACKS;                                  \
+CHAOS_SYS_CALLBACKS(u1);                        \
+CHAOS_SYS_CALLBACKS(u2);                        \
+CHAOS_SYS_CALLBACKS(u3);                        \
+CHAOS_SYS_CALLBACKS(a);                         \
+CHAOS_SYS_CALLBACKS(k);                         \
+CHAOS_SYS_CALLBACKS(Omega);
+
+#define DRIVEN_VAN_DER_POL_ATTRIBUTES           \
+ODE_ATTRIBUTES;                                 \
+CHAOS_SYS_ATTRIBUTE(u1);                        \
+CHAOS_SYS_ATTRIBUTE(u2);                        \
+CHAOS_SYS_ATTRIBUTE(u3);                        \
+CHAOS_SYS_ATTRIBUTE(a);                         \
+CHAOS_SYS_ATTRIBUTE(k);                         \
+CHAOS_SYS_ATTRIBUTE(Omega);