Squashed 'third_party/boostorg/odeint/' content from commit 6ff2719
Change-Id: If4892e29c1a5e6cf3a7aa51486a2725c251b0c7d
git-subtree-dir: third_party/boostorg/odeint
git-subtree-split: 6ff2719b6907b86596c3d43e88c1bcfdf29df560
diff --git a/examples/van_der_pol_stiff.cpp b/examples/van_der_pol_stiff.cpp
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+/*
+ * van_der_pol_stiff.cpp
+ *
+ * Created on: Dec 12, 2011
+ *
+ * Copyright 2012 Karsten Ahnert
+ * Copyright 2012-2013 Rajeev Singh
+ * Copyright 2012-2013 Mario Mulansky
+ *
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or
+ * copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+#include <iostream>
+#include <fstream>
+#include <utility>
+
+#include <boost/numeric/odeint.hpp>
+
+#include <boost/phoenix/core.hpp>
+#include <boost/phoenix/operator.hpp>
+
+using namespace std;
+using namespace boost::numeric::odeint;
+namespace phoenix = boost::phoenix;
+
+const double mu = 1000.0;
+
+
+typedef boost::numeric::ublas::vector< double > vector_type;
+typedef boost::numeric::ublas::matrix< double > matrix_type;
+
+struct vdp_stiff
+{
+ void operator()( const vector_type &x , vector_type &dxdt , double t )
+ {
+ dxdt[0] = x[1];
+ dxdt[1] = -x[0] - mu * x[1] * (x[0]*x[0]-1.0);
+ }
+};
+
+struct vdp_stiff_jacobi
+{
+ void operator()( const vector_type &x , matrix_type &J , const double &t , vector_type &dfdt )
+ {
+ J(0, 0) = 0.0;
+ J(0, 1) = 1.0;
+ J(1, 0) = -1.0 - 2.0*mu * x[0] * x[1];
+ J(1, 1) = -mu * ( x[0] * x[0] - 1.0);
+
+ dfdt[0] = 0.0;
+ dfdt[1] = 0.0;
+ }
+};
+
+
+int main( int argc , char **argv )
+{
+ //[ integrate_stiff_system
+ vector_type x( 2 );
+ /* initialize random seed: */
+ srand ( time(NULL) );
+
+ // initial conditions
+ for (int i=0; i<2; i++)
+ x[i] = 1.0; //(1.0 * rand()) / RAND_MAX;
+
+ size_t num_of_steps = integrate_const( make_dense_output< rosenbrock4< double > >( 1.0e-6 , 1.0e-6 ) ,
+ make_pair( vdp_stiff() , vdp_stiff_jacobi() ) ,
+ x , 0.0 , 1000.0 , 1.0
+ , cout << phoenix::arg_names::arg2 << " " << phoenix::arg_names::arg1[0] << " " << phoenix::arg_names::arg1[1] << "\n"
+ );
+ //]
+ clog << num_of_steps << endl;
+
+
+
+ //[ integrate_stiff_system_alternative
+
+ vector_type x2( 2 );
+ // initial conditions
+ for (int i=0; i<2; i++)
+ x2[i] = 1.0; //(1.0 * rand()) / RAND_MAX;
+
+ //size_t num_of_steps2 = integrate_const( make_dense_output< runge_kutta_dopri5< vector_type > >( 1.0e-6 , 1.0e-6 ) ,
+ // vdp_stiff() , x2 , 0.0 , 1000.0 , 1.0
+ // , cout << phoenix::arg_names::arg2 << " " << phoenix::arg_names::arg1[0] << " " << phoenix::arg_names::arg1[1] << "\n"
+ // );
+ //]
+ //clog << num_of_steps2 << endl;
+
+
+ return 0;
+}