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87 lines
2.1 KiB
C++
87 lines
2.1 KiB
C++
/*
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[auto_generated]
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libs/numeric/odeint/test/implicit_euler.cpp
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[begin_description]
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This file tests the implicit Euler stepper.
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[end_description]
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Copyright 2010-2011 Mario Mulansky
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Copyright 2010-2012 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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// disable checked iterator warning for msvc
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#include <boost/config.hpp>
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#ifdef BOOST_MSVC
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#pragma warning(disable:4996)
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#endif
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#define BOOST_TEST_MODULE odeint_implicit_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 <boost/numeric/odeint/stepper/implicit_euler.hpp>
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//#include <boost/numeric/odeint/util/ublas_resize.hpp>
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#include <boost/numeric/ublas/vector.hpp>
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#include <boost/numeric/ublas/matrix.hpp>
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using namespace boost::unit_test;
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using namespace boost::numeric::odeint;
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typedef double value_type;
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typedef boost::numeric::ublas::vector< value_type > state_type;
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typedef boost::numeric::ublas::matrix< value_type > matrix_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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dxdt( 0 ) = x( 0 ) + 2 * x( 1 );
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dxdt( 1 ) = x( 1 );
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}
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};
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struct jacobi
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{
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void operator()( const state_type &x , matrix_type &jacobi , const value_type t ) const
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{
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jacobi( 0 , 0 ) = 1;
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jacobi( 0 , 1 ) = 2;
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jacobi( 1 , 0 ) = 0;
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jacobi( 1 , 1 ) = 1;
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}
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};
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BOOST_AUTO_TEST_SUITE( implicit_euler_test )
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BOOST_AUTO_TEST_CASE( test_euler )
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{
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implicit_euler< value_type > stepper;
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state_type x( 2 );
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x(0) = 0.0; x(1) = 1.0;
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value_type eps = 1E-12;
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/* make_pair doesn't work with function pointers on msvc 10 */
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stepper.do_step( std::make_pair( sys() , jacobi() ) , x , 0.0 , 0.1 );
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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) - 20.0/81.0 ) < eps , x(0) - 20.0/81.0 );
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BOOST_CHECK_MESSAGE( abs( x(1) - 10.0/9.0 ) < eps , x(0) - 10.0/9.0 );
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}
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BOOST_AUTO_TEST_SUITE_END()
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