mfem::SecondOrderODESolver Class Reference

Abstract class for solving systems of ODEs: d2x/dt2 = f(x,dx/dt,t) More...

#include <ode.hpp>

Inheritance diagram for mfem::SecondOrderODESolver:

Collaboration diagram for mfem::SecondOrderODESolver:

Public Member Functions
	SecondOrderODESolver ()
virtual void	Init (SecondOrderTimeDependentOperator &f)
	Associate a TimeDependentOperator with the ODE solver.
virtual void	Step (Vector &x, Vector &dxdt, real_t &t, real_t &dt)=0
	Perform a time step from time t [in] to time t [out] based on the requested step size dt [in].
void	EulerStep (Vector &x, Vector &dxdt, real_t &t, real_t &dt)
void	MidPointStep (Vector &x, Vector &dxdt, real_t &t, real_t &dt)
virtual void	Run (Vector &x, Vector &dxdt, real_t &t, real_t &dt, real_t tf)
	Perform time integration from time t [in] to time tf [in].
ODEStateData &	GetState ()
	Functions for getting the state vectors.
const ODEStateData &	GetState () const
int	GetStateSize ()
	Returns how many State vectors the ODE requires.
virtual	~SecondOrderODESolver ()

Static Public Member Functions
static MFEM_EXPORT SecondOrderODESolver *	Select (const int ode_solver_type)
	Function selecting the desired SecondOrderODESolver.

Static Public Attributes
static MFEM_EXPORT std::string	Types
	Help info for SecondOrderODESolver options.

Protected Attributes
SecondOrderTimeDependentOperator *	f
	Pointer to the associated TimeDependentOperator.
MemoryType	mem_type
ODEStateDataVector	state

Detailed Description

Abstract class for solving systems of ODEs: d2x/dt2 = f(x,dx/dt,t)

Definition at line 704 of file ode.hpp.

Constructor & Destructor Documentation

SecondOrderODESolver()

mfem::SecondOrderODESolver::SecondOrderODESolver ( )

inline

Definition at line 713 of file ode.hpp.

~SecondOrderODESolver()

virtual mfem::SecondOrderODESolver::~SecondOrderODESolver ( )

inlinevirtual

Definition at line 801 of file ode.hpp.

Member Function Documentation

EulerStep()

void mfem::SecondOrderODESolver::EulerStep	(	Vector &	x,
		Vector &	dxdt,
		real_t &	t,
		real_t &	dt )

Definition at line 1091 of file ode.cpp.

GetState() [1/2]

ODEStateData & mfem::SecondOrderODESolver::GetState ( )

inline

Functions for getting the state vectors.

Definition at line 789 of file ode.hpp.

GetState() [2/2]

const ODEStateData & mfem::SecondOrderODESolver::GetState ( ) const

inline

Definition at line 790 of file ode.hpp.

GetStateSize()

int mfem::SecondOrderODESolver::GetStateSize ( )

inline

Returns how many State vectors the ODE requires.

Definition at line 793 of file ode.hpp.

Init()

void mfem::SecondOrderODESolver::Init ( SecondOrderTimeDependentOperator & f )

virtual

Associate a TimeDependentOperator with the ODE solver.

This method has to be called:

• Before the first call to Step().
• When the dimensions of the associated TimeDependentOperator change.
• When a time stepping sequence has to be restarted.
• To change the associated TimeDependentOperator.

Reimplemented in mfem::GeneralizedAlpha2Solver.

Definition at line 1119 of file ode.cpp.

MidPointStep()

void mfem::SecondOrderODESolver::MidPointStep	(	Vector &	x,
		Vector &	dxdt,
		real_t &	t,
		real_t &	dt )

Definition at line 1105 of file ode.cpp.

Run()

virtual void mfem::SecondOrderODESolver::Run ( Vector & x, Vector & dxdt, real_t & t, real_t & dt, real_t tf )

inlinevirtual

Perform time integration from time t [in] to time tf [in].

Parameters

[in,out]	x	Approximate solution.
[in,out]	dxdt	Approximate rate.
[in,out]	t	Time associated with the approximate solution x.
[in,out]	dt	Time step size.
[in]	tf	Requested final time.

The default implementation makes consecutive calls to Step() until reaching tf. The following rules describe the common behavior of the method:

• The input x [in] is the approximate solution for the input time t [in].
• The input dxdt [in] is the approximate rate for the input time t [in].
• The input dt [in] is the initial time step size.
• The output dt [out] is the last time step taken by the method which may be smaller or larger than the input dt [in] value, e.g. because of time step control.
• The output value of t [out] is not smaller than tf [in].

Definition at line 783 of file ode.hpp.

Select()

SecondOrderODESolver * mfem::SecondOrderODESolver::Select ( const int ode_solver_type )

static

Function selecting the desired SecondOrderODESolver.

Definition at line 1061 of file ode.cpp.

Step()

virtual void mfem::SecondOrderODESolver::Step ( Vector & x, Vector & dxdt, real_t & t, real_t & dt )

pure virtual

Perform a time step from time t [in] to time t [out] based on the requested step size dt [in].

Parameters

[in,out]	x	Approximate solution.
[in,out]	dxdt	Approximate rate.
[in,out]	t	Time associated with the approximate solution x and rate @ dxdt
[in,out]	dt	Time step size.

The following rules describe the common behavior of the method:

• The input x [in] is the approximate solution for the input time t [in].
• The input dxdt [in] is the approximate rate for the input time t [in].
• The input dt [in] is the desired time step size, defining the desired target time: t [target] = t [in] + dt [in].
• The output x [out] is the approximate solution for the output time t [out].
• The output dxdt [out] is the approximate rate for the output time t [out].
• The output dt [out] is the last time step taken by the method which may be smaller or larger than the input dt [in] value, e.g. because of time step control.
• The method may perform more than one time step internally; in this case dt [out] is the last internal time step size.
• The output value of t [out] may be smaller or larger than t [target], however, it is not smaller than t [in] + dt [out], if at least one internal time step was performed.
• The value x [out] may be obtained by interpolation using internally stored data.
• In some cases, the contents of x [in] may not be used, e.g. when x [out] from a previous Step() call was obtained by interpolation.
• In consecutive calls to this method, the output t [out] of one Step() call has to be the same as the input t [in] to the next Step() call.
• If the previous rule has to be broken, e.g. to restart a time stepping sequence, then the ODE solver must be re-initialized by calling Init() between the two Step() calls.

Implemented in mfem::GeneralizedAlpha2Solver, and mfem::NewmarkSolver.

Member Data Documentation

f

SecondOrderTimeDependentOperator* mfem::SecondOrderODESolver::f

protected

Pointer to the associated TimeDependentOperator.

Definition at line 708 of file ode.hpp.

mem_type

MemoryType mfem::SecondOrderODESolver::mem_type

protected

Definition at line 709 of file ode.hpp.

state

ODEStateDataVector mfem::SecondOrderODESolver::state

protected

Definition at line 710 of file ode.hpp.

Types

std::string mfem::SecondOrderODESolver::Types

static

Initial value:

=
   "ODE solver: \n\t"
   "  [0--10] - GeneralizedAlpha(0.1 * s),\n\t"
   "  11 - Average Acceleration, 12 - Linear Acceleration\n\t"
   "  13 - CentralDifference, 14 - FoxGoodwin"

Help info for SecondOrderODESolver options.

Definition at line 796 of file ode.hpp.

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The documentation for this class was generated from the following files:

• linalg/ode.hpp
• linalg/ode.cpp