1 files changed, 94 insertions, 0 deletions
diff --git a/chaos/src/duffing.hpp b/chaos/src/duffing.hpp
new file mode 100644
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+++ b/chaos/src/duffing.hpp
@@ -0,0 +1,94 @@
+//
+//
+//  chaos~
+//  Copyright (C) 2005  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"
+
+//  duffing equation: dx/dt = y
+//                    dy/dt = x * (1 - x^2) + R*cos(omega * t) - gamma * y
+//
+
+
+class duffing:
+    public ode_base<2>
+{
+public:
+    duffing()
+    {
+        CHAOS_PAR_INIT(method,0);
+        CHAOS_PAR_INIT(dt,0.01);
+
+        CHAOS_SYS_INIT(x, 0.5, 0);
+        CHAOS_SYS_INIT(y, 0.5, 1);
+
+        CHAOS_PAR_INIT(R, 0.4);
+        CHAOS_PAR_INIT(omega, 1);
+        CHAOS_PAR_INIT(gamma, 0.25);
+
+        t = 0;
+    }
+
+
+    virtual void m_system(data_t* deriv, data_t* data)
+    {
+        data_t x = data[0], y = data[1];
+
+        deriv[0] = y;
+        deriv[1] = x * (1 - x*x) +
+            CHAOS_PARAMETER(R) * cos( CHAOS_PARAMETER(omega) * t) -
+            CHAOS_PARAMETER(gamma) * y;
+        t += CHAOS_PARAMETER(dt);
+        t = std::fmod(t, data_t(M_PI));
+    }
+
+    virtual void m_verify()
+    {
+        if (m_data[0] == 0 && m_data[1] == 0 && m_data[2] == 0)
+            for (int i = 0; i != 3; ++i)
+                m_data[i] = rand_range(0,3);
+    }
+
+
+    CHAOS_SYSVAR_FUNCS(x,0);
+    CHAOS_SYSVAR_FUNCS(y,1);
+
+    CHAOS_SYSPAR_FUNCS(R);
+    CHAOS_SYSPAR_FUNCS(omega);
+    CHAOS_SYSPAR_FUNCS(gamma);
+
+private:
+    data_t t;
+};
+
+#define DUFFING_CALLBACKS                       \
+ODE_CALLBACKS;                                  \
+CHAOS_SYS_CALLBACKS(x);                         \
+CHAOS_SYS_CALLBACKS(y);                         \
+CHAOS_SYS_CALLBACKS(R);                         \
+CHAOS_SYS_CALLBACKS(gamma);                     \
+CHAOS_SYS_CALLBACKS(omega);
+
+#define DUFFING_ATTRIBUTES                      \
+ODE_ATTRIBUTES;                                 \
+CHAOS_SYS_ATTRIBUTE(x);                         \
+CHAOS_SYS_ATTRIBUTE(y);                         \
+CHAOS_SYS_ATTRIBUTE(R);                         \
+CHAOS_SYS_ATTRIBUTE(gamma);                     \
+CHAOS_SYS_ATTRIBUTE(omega);
+