mfem::ExplicitRKSolver Class Reference

#include <ode.hpp>

Inheritance diagram for mfem::ExplicitRKSolver:

Collaboration diagram for mfem::ExplicitRKSolver:

Public Member Functions
	ExplicitRKSolver (int s_, const real_t *a_, const real_t *b_, const real_t *c_)
void	Init (TimeDependentOperator &f_) override
	Associate a TimeDependentOperator with the ODE solver.
void	Step (Vector &x, real_t &t, real_t &dt) override
	Perform a time step from time t [in] to time t [out] based on the requested step size dt [in].
virtual	~ExplicitRKSolver ()
Public Member Functions inherited from mfem::ODESolver
	ODESolver ()
virtual void	Run (Vector &x, real_t &t, real_t &dt, real_t tf)
	Perform time integration from time t [in] to time tf [in].
virtual int	GetStateSize ()
	Returns how many State vectors the ODE requires.
virtual	~ODESolver ()

Additional Inherited Members
Static Public Member Functions inherited from mfem::ODESolver
static MFEM_EXPORT std::unique_ptr< ODESolver >	Select (const int ode_solver_type)
static MFEM_EXPORT std::unique_ptr< ODESolver >	SelectExplicit (const int ode_solver_type)
static MFEM_EXPORT std::unique_ptr< ODESolver >	SelectImplicit (const int ode_solver_type)
Static Public Attributes inherited from mfem::ODESolver
static MFEM_EXPORT std::string	ExplicitTypes
static MFEM_EXPORT std::string	ImplicitTypes
static MFEM_EXPORT std::string	Types
Protected Attributes inherited from mfem::ODESolver
TimeDependentOperator *	f
	Pointer to the associated TimeDependentOperator.
MemoryType	mem_type

Detailed Description

An explicit Runge-Kutta method corresponding to a general Butcher tableau +-----—+-------------------—+ | c[0] | a[0] | | c[1] | a[1] a[2] | | ... | ... | | c[s-2] | ... a[s(s-1)/2-1] | +-----—+-------------------—+ | | b[0] b[1] ... b[s-1] | +-----—+-------------------—+

Definition at line 292 of file ode.hpp.

Constructor & Destructor Documentation

ExplicitRKSolver()

mfem::ExplicitRKSolver::ExplicitRKSolver	(	int	s_,
		const real_t *	a_,
		const real_t *	b_,
		const real_t *	c_ )

Definition at line 281 of file ode.cpp.

~ExplicitRKSolver()

mfem::ExplicitRKSolver::~ExplicitRKSolver ( )

virtual

Definition at line 332 of file ode.cpp.

Member Function Documentation

Init()

void mfem::ExplicitRKSolver::Init ( TimeDependentOperator & f_ )

overridevirtual

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 from mfem::ODESolver.

Definition at line 291 of file ode.cpp.

Step()

void mfem::ExplicitRKSolver::Step ( Vector & x, real_t & t, real_t & dt )

overridevirtual

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]	t	Time associated with the approximate solution x.
[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 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 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.

Implements mfem::ODESolver.

Definition at line 302 of file ode.cpp.

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

• linalg/ode.hpp
• linalg/ode.cpp