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-rw-r--r--src/vZ/integrator.hpp83
-rw-r--r--src/vZ/simple.hpp56
2 files changed, 139 insertions, 0 deletions
diff --git a/src/vZ/integrator.hpp b/src/vZ/integrator.hpp
new file mode 100644
index 0000000..394f40f
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+++ b/src/vZ/integrator.hpp
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+/*************************************************************************
+ * 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_INTEGRATOR_HPP
+#define VZ_INTEGRATOR_HPP
+
+#include <tr1/functional>
+#include <algorithm>
+
+namespace vZ
+{
+ // Base Integrator class
+ //
+ // All integration methods derrive from this class
+ // If the initial value problem is specified as
+ // y' = f(t, y); y(t0) = y0
+ // then an Integrator could be constructed as Integrator(f, dt).y(y0).t(t0)
+ template <typename Real>
+ class GenericIntegrator
+ {
+ public:
+ typedef std::tr1::function<Real (Real, Real)> Function;
+
+ // By default, y and t start at zero
+ GenericIntegrator(Function f, Real dt)
+ : m_f(f), m_y(0), m_t(0), m_dt(dt) { }
+ virtual ~GenericIntegrator() { }
+
+ GenericIntegrator& y(Real y) { m_y = y; return *this; }
+ GenericIntegrator& t(Real t) { m_t = t; return *this; }
+ GenericIntegrator& dt(Real dt) { m_dt = dt; return *this; }
+
+ Real y() const { return m_y; }
+ Real t() const { return m_t; }
+ Real dt() const { return m_dt; }
+
+ // Integrate until time t
+ void integrate(Real t_final);
+
+ protected:
+ virtual void step(Real& t, Real& dt) = 0;
+ Function m_f;
+
+ private:
+ Real m_y;
+ Real m_t, m_dt;
+ };
+
+ // Type alias
+ typedef GenericIntegrator<double> Integrator;
+
+ // Definitions
+
+ template <typename Real>
+ void
+ GenericIntegrator<Real>::integrate(Real t_final)
+ {
+ while (m_t < t_final) {
+ m_dt = std::min(m_dt, t_final - m_t);
+ step(m_t, m_dt);
+ }
+ }
+}
+
+
+#endif // VZ_INTEGRATOR_HPP
diff --git a/src/vZ/simple.hpp b/src/vZ/simple.hpp
new file mode 100644
index 0000000..65b7560
--- /dev/null
+++ b/src/vZ/simple.hpp
@@ -0,0 +1,56 @@
+/*************************************************************************
+ * 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_SIMPLE_HPP
+#define VZ_SIMPLE_HPP
+
+#include <vector>
+
+namespace vZ
+{
+ // Base class for non-adaptive RK-style algorithms
+ template <typename Real>
+ class GenericSimpleIntegrator : public GenericIntegrator<Real>
+ {
+ public:
+ typedef typename GenericIntegrator<Real>::Function Function;
+
+ // Coefficients in the tableau representation of the RK algorithm
+ typedef std::vector<std::vector<Real> > ACoefficients;
+ typedef std::vector<Real> BCoefficients;
+
+ GenericSimpleIntegrator(Function f, Real dt,
+ ACoefficients a, BCoefficients b)
+ : GenericIntegrator<Real>(f, dt), m_a(a), m_b(b) { }
+ virtual ~GenericSimpleIntegrator() { }
+
+ protected:
+ virtual void step(Real& t, Real& dt);
+
+ private:
+ ACoefficients m_a;
+ BCoefficients m_b;
+ };
+
+ // Type alias
+ typedef GenericSimpleIntegrator<double> SimpleIntegrator;
+}
+
+#endif // VZ_SIMPLE_HPP