mfem::GeneralizedAlpha2Solver Class Reference

#include <ode.hpp>

Inheritance diagram for mfem::GeneralizedAlpha2Solver:

Collaboration diagram for mfem::GeneralizedAlpha2Solver:

Public Member Functions
	GeneralizedAlpha2Solver (double rho_inf=1.0)
virtual void	PrintProperties (std::ostream &out=mfem::out)
virtual void	Init (SecondOrderTimeDependentOperator &_f)
	Associate a TimeDependentOperator with the ODE solver. More...
virtual void	Step (Vector &x, Vector &dxdt, double &t, double &dt)
	Perform a time step from time t [in] to time t [out] based on the requested step size dt [in]. More...
Public Member Functions inherited from mfem::SecondOrderODESolver
	SecondOrderODESolver ()
virtual void	Run (Vector &x, Vector &dxdt, double &t, double &dt, double tf)
	Perform time integration from time t [in] to time tf [in]. More...
virtual	~SecondOrderODESolver ()

Protected Attributes
Vector	xa
Vector	va
Vector	aa
Vector	d2xdt2
double	alpha_f
double	alpha_m
double	beta
double	gamma
bool	first
Protected Attributes inherited from mfem::SecondOrderODESolver
SecondOrderTimeDependentOperator *	f
	Pointer to the associated TimeDependentOperator. More...
MemoryType	mem_type

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 659 of file ode.hpp.

Constructor & Destructor Documentation

mfem::GeneralizedAlpha2Solver::GeneralizedAlpha2Solver ( double  rho_inf = 1.0 )

inline

Definition at line 667 of file ode.hpp.

Member Function Documentation

void mfem::GeneralizedAlpha2Solver::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 from mfem::SecondOrderODESolver.

Definition at line 887 of file ode.cpp.

void mfem::GeneralizedAlpha2Solver::PrintProperties ( std::ostream &  out = mfem::out )

virtual

Definition at line 898 of file ode.cpp.

void mfem::GeneralizedAlpha2Solver::Step ( Vector &  x, Vector &  dxdt, double &  t, double &  dt  )

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.

Implements mfem::SecondOrderODESolver.

Definition at line 927 of file ode.cpp.

Member Data Documentation

Vector mfem::GeneralizedAlpha2Solver::aa

protected

Definition at line 662 of file ode.hpp.

double mfem::GeneralizedAlpha2Solver::alpha_f

protected

Definition at line 663 of file ode.hpp.

double mfem::GeneralizedAlpha2Solver::alpha_m

protected

Definition at line 663 of file ode.hpp.

double mfem::GeneralizedAlpha2Solver::beta

protected

Definition at line 663 of file ode.hpp.

Vector mfem::GeneralizedAlpha2Solver::d2xdt2

protected

Definition at line 662 of file ode.hpp.

bool mfem::GeneralizedAlpha2Solver::first

protected

Definition at line 664 of file ode.hpp.

double mfem::GeneralizedAlpha2Solver::gamma

protected

Definition at line 663 of file ode.hpp.

Vector mfem::GeneralizedAlpha2Solver::va

protected

Definition at line 662 of file ode.hpp.

Vector mfem::GeneralizedAlpha2Solver::xa

protected

Definition at line 662 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