[Boost-commit] svn:boost r57585 - sandbox/odeint/libs/numeric/odeint/examples

Subject: [Boost-commit] svn:boost r57585 - sandbox/odeint/libs/numeric/odeint/examples
From: mario.mulansky_at_[hidden]
Date: 2009-11-11 17:09:01

Author: mariomulansky
Date: 2009-11-11 17:09:01 EST (Wed, 11 Nov 2009)
New Revision: 57585
URL: http://svn.boost.org/trac/boost/changeset/57585

Log:
+pendulum_vibrating_pivot
Added:
   sandbox/odeint/libs/numeric/odeint/examples/pendulum_vibrating_pivot.cpp   (contents, props changed)

Added: sandbox/odeint/libs/numeric/odeint/examples/pendulum_vibrating_pivot.cpp
==============================================================================
--- (empty file)
+++ sandbox/odeint/libs/numeric/odeint/examples/pendulum_vibrating_pivot.cpp	2009-11-11 17:09:01 EST (Wed, 11 Nov 2009)
@@ -0,0 +1,75 @@
+/* Boost numeric/odeint/examples/coupled_vdp.cpp
+ 
+ Copyright 2009 Karsten Ahnert
+ Copyright 2009 Mario Mulansky
+
+ Shows the usage of odeint by integrating the equations of a 
+ pendulum with horizontally vibrating pivot:
+
+ 
+
+ 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 <vector>
+#include <list>
+#include <tr1/array>
+
+#include <boost/numeric/odeint.hpp>
+
+#define tab "\t"
+
+using namespace std;
+using namespace boost::numeric::odeint;
+
+
+typedef std::tr1::array< double , 2 > state_type;
+
+const double alpha = 0.1;
+const double omega = 10;
+const double a = 0.1;
+const size_t time_points = 1000;
+
+/* 
+   Defines the right hand side f(x,t) of the dynamical equations dx/dt = f(x,t) 
+   x consists of x=(x, dx/dt) and f has explicit time dependence
+*/
+void my_system( state_type &x , state_type &dxdt , double t ) 
+{
+    dxdt[0] = x[1];
+    dxdt[1] = -sin(x[0]) - alpha*x[1] + a*omega*omega*sin(omega*t)*cos(x[0]);
+}
+
+int main( int argc , char **argv )
+{
+    state_type x = {{ 1.0, 0.0 }};
+
+    vector<double> times(time_points);
+    for( size_t i=0; i<time_points; i++ ) {
+        times[i] = 0.1*i;
+    }
+    vector<state_type> x_t_vec;
+    
+    stepper_half_step< stepper_rk4< state_type > > stepper;
+
+    size_t steps = integrate( stepper, my_system, x, times, back_inserter(x_t_vec));
+
+        clog << "Steps: " << steps << endl;
+
+    cout.precision(5);
+    cout.setf(ios::fixed,ios::floatfield);
+    
+
+    for( size_t i=0; i<time_points; i++ ) {
+        //cout << "current state: " ;
+        cout << times[i] << tab;
+        cout << x_t_vec[i][0] << tab << x_t_vec[i][1] << tab << x_t_vec[i][2] << endl;
+    }
+
+    return 0;
+
+}