106 lines
2.3 KiB
C++
106 lines
2.3 KiB
C++
/*
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[auto_generated]
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libs/numeric/odeint/test/euler_stepper.cpp
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[begin_description]
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This file tests explicit Euler stepper.
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[end_description]
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Copyright 2011 Mario Mulansky
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Copyright 2012 Karsten Ahnert
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or
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copy at http://www.boost.org/LICENSE_1_0.txt)
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*/
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#define BOOST_TEST_MODULE odeint_explicit_euler
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#include <boost/test/unit_test.hpp>
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#include <utility>
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#include <iostream>
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#include <vector>
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#include <boost/numeric/odeint/stepper/euler.hpp>
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#include <boost/numeric/odeint/algebra/range_algebra.hpp>
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using namespace boost::unit_test;
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using namespace boost::numeric::odeint;
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// test with own vector implementation
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class my_vec : public std::vector< double > {
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public:
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my_vec() : std::vector< double >()
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{ }
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my_vec( const my_vec &x ) : std::vector< double >( x )
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{ }
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my_vec( size_t dim )
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: std::vector< double >( dim )
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{ }
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};
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namespace boost {
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namespace numeric {
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namespace odeint {
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template<>
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struct is_resizeable< my_vec >
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{
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//struct type : public boost::true_type { };
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typedef boost::true_type type;
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const static bool value = type::value;
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};
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} } }
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typedef double value_type;
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//typedef std::vector< value_type > state_type;
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typedef my_vec state_type;
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/* use functors, because functions don't work with msvc 10, I guess this is a bug */
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struct sys
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{
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void operator()( const state_type &x , state_type &dxdt , const value_type t ) const
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{
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std::cout << "sys start " << dxdt.size() << std::endl;
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dxdt[0] = x[0] + 2 * x[1];
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dxdt[1] = x[1];
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std::cout << "sys done" << std::endl;
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}
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};
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BOOST_AUTO_TEST_SUITE( explicit_euler_test )
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BOOST_AUTO_TEST_CASE( test_euler )
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{
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range_algebra algebra;
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euler< state_type > stepper( algebra );
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state_type x( 2 );
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x[0] = 0.0; x[1] = 1.0;
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std::cout << "initialized" << std::endl;
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const value_type eps = 1E-12;
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const value_type dt = 0.1;
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stepper.do_step( sys() , x , 0.0 , dt );
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using std::abs;
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// compare with analytic solution of above system
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BOOST_CHECK_MESSAGE( abs( x[0] - 2.0*1.0*dt ) < eps , x[0] - 2.0*1.0*dt );
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BOOST_CHECK_MESSAGE( abs( x[1] - (1.0 + dt) ) < eps , x[1] - (1.0+dt) );
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}
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BOOST_AUTO_TEST_SUITE_END()
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