/usr/include/libmesh/euler2_solver.h is in libmesh-dev 0.7.1-2ubuntu1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | // $Id: euler2_solver.h 3874 2010-07-02 21:57:26Z roystgnr $
// The libMesh Finite Element Library.
// Copyright (C) 2002-2008 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
// This 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 2.1 of the License, or (at your option) any later version.
// This 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 library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#ifndef __euler2_solver_h__
#define __euler2_solver_h__
// C++ includes
// Local includes
#include "unsteady_solver.h"
namespace libMesh
{
/**
* This class defines a theta-method (defaulting to Backward
* Euler with theta = 1.0) solver to handle
* time integration of DifferentiableSystems.
* The "Euler2" solver differs from Euler in how it evaluates
* residuals at intermediate theta values:
* Euler solves u' = f(theta*u_new + (1-theta)*u_old),
* Euler2 solves u' = theta*f(u_new) + (1-theta)*f(u_old)
* i.e. the trapezoidal rule for theta = 0.5
*
* This class is part of the new DifferentiableSystem framework,
* which is still experimental. Users of this framework should
* beware of bugs and future API changes.
*
* @author Roy H. Stogner 2006
*/
// ------------------------------------------------------------
// Solver class definition
class Euler2Solver : public UnsteadySolver
{
public:
/**
* The parent class
*/
typedef UnsteadySolver Parent;
/**
* Constructor. Requires a reference to the system
* to be solved.
*/
Euler2Solver (sys_type& s);
/**
* Destructor.
*/
virtual ~Euler2Solver ();
/**
* Error convergence order: 2 for Crank-Nicolson, 1 otherwise
*/
virtual Real error_order() const;
/**
* This method uses the DifferentiableSystem's
* element_time_derivative() and element_constraint()
* to build a full residual on an element. What combination
* it uses will depend on theta.
*/
virtual bool element_residual (bool request_jacobian,
DiffContext&);
/**
* This method uses the DifferentiableSystem's
* side_time_derivative() and side_constraint()
* to build a full residual on an element's side.
* What combination it uses will depend on theta.
*/
virtual bool side_residual (bool request_jacobian,
DiffContext&);
/**
* The value for the theta method to employ: 1.0 corresponds
* to backwards Euler, 0.0 corresponds to forwards Euler,
* 0.5 corresponds to a Crank-Nicolson-like scheme.
*/
Real theta;
};
} // namespace libMesh
#endif // #define __euler2_solver_h__
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