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

#include <ode.hpp>

Inheritance diagram for mfem::ODESolver:

Collaboration diagram for mfem::ODESolver:

Public Member Functions
	ODESolver ()

virtual void	Init (TimeDependentOperator &f_)
	Associate a TimeDependentOperator with the ODE solver.

virtual void	Step (Vector &x, 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].

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 bool	SupportsImplicitVariableType (ImplicitVariableType var) const
	Returns true if the ODESolver supports the given ImplicitVariableType, var, and returns false otherwise. Default implementation returns true if var is ImplicitVariableType::SLOPE and false otherwise.

void	SetImplicitVariableType (const ImplicitVariableType variable_type)
	Sets the ImplicitVariableType for the TimeDependentOperator, if supported.

virtual void	ComputeSlopeFromState (const real_t dt, const Vector &u, Vector &k)
	Compute the finite-difference slope, \(\frac{du}{dt} \approx \frac{u(t+dt)-u(t)}{dt}\), and store it in k.

virtual	~ODESolver ()

Static Public Member Functions
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 MFEM_EXPORT std::unique_ptr< ODESolver >	SelectIMEX (const int ode_solver_type)

Static Public Attributes
static MFEM_EXPORT std::string	ExplicitTypes

static MFEM_EXPORT std::string	ImplicitTypes

static MFEM_EXPORT std::string	IMEXTypes

static MFEM_EXPORT std::string	Types

Protected Types
using	ImplicitVariableType = TimeDependentOperator::ImplicitVariableType

Protected Attributes
TimeDependentOperator *	f
	Pointer to the associated TimeDependentOperator.

MemoryType	mem_type

Detailed Description

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

For systems of split ODEs:

\[ M dx/dt = f_1(x,t) + f_2(x,t) \]

where \( M^{-1} f_1 \) and \( M^{-1} f_2 \) are treated differently (e.g., explicitly and implicitly), the solver class expects a TimeDependentOperator with split functionality. Setting TimeDependentOperator::EvalMode = TimeDependentOperator::ADDITIVE_TERM_1 and calling TimeDependentOperator::Mult() should return \( k_1=M^{-1} f_1(x,t) \). Setting TimeDependentOperator::EvalMode = TimeDependentOperator::ADDITIVE_TERM_2 and calling TimeDependentOperator::ImplicitSolve() should solve \( M k_2 = f_2(x+\gamma k_2,t) \).

Definition at line 120 of file ode.hpp.

Member Typedef Documentation

◆ ImplicitVariableType

using mfem::ODESolver::ImplicitVariableType = TimeDependentOperator::ImplicitVariableType

protected

Definition at line 123 of file ode.hpp.

Constructor & Destructor Documentation

◆ ODESolver()

mfem::ODESolver::ODESolver ( )

inline

Definition at line 129 of file ode.hpp.

◆ ~ODESolver()

virtual mfem::ODESolver::~ODESolver ( )

inlinevirtual

Definition at line 261 of file ode.hpp.

Member Function Documentation

◆ ComputeSlopeFromState()

void mfem::ODESolver::ComputeSlopeFromState	(	const real_t	dt,
		const Vector &	u,
		Vector &	k )

virtual

Compute the finite-difference slope, \(\frac{du}{dt} \approx \frac{u(t+dt)-u(t)}{dt}\), and store it in k.

Parameters

[in]	dt	Finite difference step size.
[in]	u	state vector, u(t).
[in,out]	k	On input, k contains the state vector, u( t+ dt). On output, k contains the computed slope, du/dt.

Definition at line 194 of file ode.cpp.

◆ GetStateSize()

virtual int mfem::ODESolver::GetStateSize ( )

inlinevirtual

Returns how many State vectors the ODE requires.

Reimplemented in mfem::ODESolverWithStates.

Definition at line 194 of file ode.hpp.

◆ Init()

void mfem::ODESolver::Init ( TimeDependentOperator & 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::AdamsBashforthSolver, mfem::AdamsMoultonSolver, mfem::ARKStepSolver, mfem::BackwardEulerSolver, mfem::CVODESolver, mfem::ESDIRK32Solver, mfem::ESDIRK33Solver, mfem::ExplicitRKSolver, mfem::ForwardEulerSolver, mfem::GeneralizedAlphaSolver, mfem::IMEX_DIRK_RK3, mfem::IMEXExpImplEuler, mfem::IMEXRK2, mfem::IMEXRK2_3StageExplicit, mfem::ImplicitMidpointSolver, mfem::PetscODESolver, mfem::RK2Solver, mfem::RK3SSPSolver, mfem::RK4Solver, mfem::SDIRK23Solver, mfem::SDIRK33Solver, mfem::SDIRK34Solver, and mfem::TrapezoidalRuleSolver.

Definition at line 182 of file ode.cpp.

◆ Run()

virtual void mfem::ODESolver::Run	(	Vector &	x,
		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]	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 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].

Reimplemented in mfem::PetscODESolver.

Definition at line 188 of file ode.hpp.

◆ Select()

std::unique_ptr< ODESolver > mfem::ODESolver::Select ( const int ode_solver_type )

static

Function for selecting the desired ODESolver (Explicit and Implicit) Returns an ODESolver pointer based on an type Caller gets ownership of the object and is responsible for its deletion

Definition at line 41 of file ode.cpp.

◆ SelectExplicit()

std::unique_ptr< ODESolver > mfem::ODESolver::SelectExplicit ( const int ode_solver_type )

static

Function for selecting the desired Explicit ODESolver Returns an ODESolver pointer based on an type Caller gets ownership of the object and is responsible for its deletion

Definition at line 53 of file ode.cpp.

◆ SelectIMEX()

std::unique_ptr< ODESolver > mfem::ODESolver::SelectIMEX ( const int ode_solver_type )

static

Function for selecting the desired IMEX ODESolver Returns an ODESolver pointer based on an type Caller gets ownership of the object and is responsible for its deletion

Definition at line 116 of file ode.cpp.

◆ SelectImplicit()

std::unique_ptr< ODESolver > mfem::ODESolver::SelectImplicit ( const int ode_solver_type )

static

Function for selecting the desired Implicit ODESolver Returns an ODESolver pointer based on an type Caller gets ownership of the object and is responsible for its deletion

Definition at line 77 of file ode.cpp.

◆ SetImplicitVariableType()

void mfem::ODESolver::SetImplicitVariableType ( const ImplicitVariableType variable_type )

inline

Sets the ImplicitVariableType for the TimeDependentOperator, if supported.

Note: This should be called after Init().

Definition at line 207 of file ode.hpp.

◆ Step()

virtual void mfem::ODESolver::Step	(	Vector &	x,
		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]	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.

Implemented in mfem::AdamsBashforthSolver, mfem::AdamsMoultonSolver, mfem::ARKStepSolver, mfem::BackwardEulerSolver, mfem::ESDIRK32Solver, mfem::ESDIRK33Solver, mfem::ExplicitRKSolver, mfem::ForwardEulerSolver, mfem::GeneralizedAlphaSolver, mfem::IMEX_DIRK_RK3, mfem::IMEXExpImplEuler, mfem::IMEXRK2, mfem::IMEXRK2_3StageExplicit, mfem::ImplicitMidpointSolver, mfem::PetscODESolver, mfem::RK2Solver, mfem::RK3SSPSolver, mfem::RK4Solver, mfem::SDIRK23Solver, mfem::SDIRK33Solver, mfem::SDIRK34Solver, and mfem::TrapezoidalRuleSolver.

◆ SupportsImplicitVariableType()

virtual bool mfem::ODESolver::SupportsImplicitVariableType ( ImplicitVariableType var ) const

inlinevirtual

Returns true if the ODESolver supports the given ImplicitVariableType, var, and returns false otherwise. Default implementation returns true if var is ImplicitVariableType::SLOPE and false otherwise.

Warning: Should be overridden in ODESolver that calls TimeDependentOperator::ImplicitSolve().

Reimplemented in mfem::AdamsMoultonSolver, mfem::BackwardEulerSolver, mfem::ESDIRK32Solver, mfem::ESDIRK33Solver, mfem::GeneralizedAlphaSolver, mfem::IMEX_DIRK_RK3, mfem::IMEXExpImplEuler, mfem::IMEXRK2, mfem::IMEXRK2_3StageExplicit, mfem::ImplicitMidpointSolver, mfem::SDIRK23Solver, mfem::SDIRK33Solver, mfem::SDIRK34Solver, and mfem::TrapezoidalRuleSolver.

Definition at line 201 of file ode.hpp.

Member Data Documentation

◆ ExplicitTypes

std::string mfem::ODESolver::ExplicitTypes

static

Initial value:

=
   "\n\tExplicit solver: \n\t"
   "        RK      :  1 - Forward Euler, 2 - RK2(0.5), 3 - RK3 SSP, 4 - RK4, 6 - RK6,\n\t"
   "        AB      : 11 - AB1, 12 - AB2, 13 - AB3, 14 - AB4, 15 - AB5\n"

Definition at line 232 of file ode.hpp.

◆ f

TimeDependentOperator* mfem::ODESolver::f

protected

Pointer to the associated TimeDependentOperator.

Definition at line 125 of file ode.hpp.

◆ IMEXTypes

std::string mfem::ODESolver::IMEXTypes

static

Initial value:

=
   "\n\tIMEX solver: \n\t"
   "        (L-Stab): 61 - Forward Backward Euler, 62 - IMEXRK2(2,2,2),\n\t"
   "                  63 - IMEXRK2(2,3,2), 64 - IMEX_DIRK_RK3\n"

Definition at line 234 of file ode.hpp.

◆ ImplicitTypes

std::string mfem::ODESolver::ImplicitTypes

static

Initial value:

=
   "\n\tImplicit solver: \n\t"
   "        (L-Stab): 21 - Backward Euler, 22 - SDIRK23(2), 23 - SDIRK33,\n\t"
   "        (A-Stab): 32 - Implicit Midpoint, 33 - SDIRK23, 34 - SDIRK34,\n\t"
   "        GA      : 40 -- 50  - Generalized-alpha,\n\t"
   "        AM      : 51 - AM1, 52 - AM2, 53 - AM3, 54 - AM4\n"

Definition at line 233 of file ode.hpp.

◆ mem_type

MemoryType mfem::ODESolver::mem_type

protected

Definition at line 126 of file ode.hpp.

◆ Types

std::string mfem::ODESolver::Types

static

Initial value:

= ODESolver::ExplicitTypes +
                               ODESolver::ImplicitTypes +
                               ODESolver::IMEXTypes

Definition at line 235 of file ode.hpp.

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

linalg/ode.hpp
linalg/ode.cpp

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Types

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ ImplicitVariableType

Constructor & Destructor Documentation

◆ ODESolver()

◆ ~ODESolver()

Member Function Documentation

◆ ComputeSlopeFromState()

◆ GetStateSize()

◆ Init()

◆ Run()

◆ Select()

◆ SelectExplicit()

◆ SelectIMEX()

◆ SelectImplicit()

◆ SetImplicitVariableType()

◆ Step()

◆ SupportsImplicitVariableType()

Member Data Documentation

◆ ExplicitTypes

◆ f

◆ IMEXTypes

◆ ImplicitTypes

◆ mem_type

◆ Types