mfem::GeneralizedAlpha2Solver Class Reference

#include <ode.hpp>

Inheritance diagram for mfem::GeneralizedAlpha2Solver:

Collaboration diagram for mfem::GeneralizedAlpha2Solver:

Public Member Functions
	GeneralizedAlpha2Solver (real_t rho_inf=1.0, bool no_mult_=false)
void	PrintProperties (std::ostream &os=mfem::out)
void	Init (SecondOrderTimeDependentOperator &f_) override
	Associate a TimeDependentOperator with the ODE solver.
void	Step (Vector &x, Vector &dxdt, 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].
Public Member Functions inherited from mfem::SecondOrderODESolver
	SecondOrderODESolver ()
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 ()

Protected Attributes
Vector	xa
Vector	va
Vector	aa
real_t	alpha_f
real_t	alpha_m
real_t	beta
real_t	gamma
bool	no_mult
Protected Attributes inherited from mfem::SecondOrderODESolver
SecondOrderTimeDependentOperator *	f
	Pointer to the associated TimeDependentOperator.
MemoryType	mem_type
ODEStateDataVector	state

Additional Inherited Members
Static Public Member Functions inherited from mfem::SecondOrderODESolver
static MFEM_EXPORT SecondOrderODESolver *	Select (const int ode_solver_type)
	Function selecting the desired SecondOrderODESolver.
Static Public Attributes inherited from mfem::SecondOrderODESolver
static MFEM_EXPORT std::string	Types
	Help info for SecondOrderODESolver options.

Detailed Description

Generalized-alpha ODE solver A Time Integration Algorithm for Structural Dynamics With Improved Numerical Dissipation: The Generalized-α Method J.Chung and G.M. Hulbert, J. Appl. Mech 60(2), 371-375, 1993 https://doi.org/10.1115/1.2900803 rho_inf in [0,1]

Definition at line 850 of file ode.hpp.

Constructor & Destructor Documentation

GeneralizedAlpha2Solver()

mfem::GeneralizedAlpha2Solver::GeneralizedAlpha2Solver ( real_t rho_inf = 1.0, bool no_mult_ = false )

inline

Definition at line 858 of file ode.hpp.

Member Function Documentation

Init()

void mfem::GeneralizedAlpha2Solver::Init ( SecondOrderTimeDependentOperator & 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::SecondOrderODESolver.

Definition at line 1191 of file ode.cpp.

PrintProperties()

void mfem::GeneralizedAlpha2Solver::PrintProperties

(

std::ostream &

os = mfem::out

)

Definition at line 1199 of file ode.cpp.

Step()

void mfem::GeneralizedAlpha2Solver::Step ( Vector & x, Vector & dxdt, 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]	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.

Implements mfem::SecondOrderODESolver.

Definition at line 1229 of file ode.cpp.

Member Data Documentation

aa

Vector mfem::GeneralizedAlpha2Solver::aa

protected

Definition at line 853 of file ode.hpp.

alpha_f

real_t mfem::GeneralizedAlpha2Solver::alpha_f

protected

Definition at line 854 of file ode.hpp.

alpha_m

real_t mfem::GeneralizedAlpha2Solver::alpha_m

protected

Definition at line 854 of file ode.hpp.

beta

real_t mfem::GeneralizedAlpha2Solver::beta

protected

Definition at line 854 of file ode.hpp.

gamma

real_t mfem::GeneralizedAlpha2Solver::gamma

protected

Definition at line 854 of file ode.hpp.

no_mult

bool mfem::GeneralizedAlpha2Solver::no_mult

protected

Definition at line 855 of file ode.hpp.

va

Vector mfem::GeneralizedAlpha2Solver::va

protected

Definition at line 853 of file ode.hpp.

xa

Vector mfem::GeneralizedAlpha2Solver::xa

protected

Definition at line 853 of file ode.hpp.

---

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

• linalg/ode.hpp
• linalg/ode.cpp