MFEM  v4.5.0 Finite element discretization library
mfem::NewmarkSolver Class Reference

#include <ode.hpp>

Inheritance diagram for mfem::NewmarkSolver:
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Collaboration diagram for mfem::NewmarkSolver:
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## Public Member Functions

NewmarkSolver (double beta_=0.25, double gamma_=0.5)

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

void Init (SecondOrderTimeDependentOperator &f_) override
Associate a TimeDependentOperator with the ODE solver. More...

void Step (Vector &x, Vector &dxdt, double &t, double &dt) override
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 int GetMaxStateSize ()
Function for getting and setting the state vectors. More...

virtual int GetStateSize ()

virtual const VectorGetStateVector (int i)

virtual void GetStateVector (int i, Vector &state)

virtual void SetStateVector (int i, Vector &state)

virtual ~SecondOrderODESolver ()

## Additional Inherited Members

Protected Attributes inherited from mfem::SecondOrderODESolver
SecondOrderTimeDependentOperatorf
Pointer to the associated TimeDependentOperator. More...

MemoryType mem_type

## Detailed Description

The classical newmark method. Newmark, N. M. (1959) A method of computation for structural dynamics. Journal of Engineering Mechanics, ASCE, 85 (EM3) 67-94.

Definition at line 711 of file ode.hpp.

## ◆ NewmarkSolver()

 mfem::NewmarkSolver::NewmarkSolver ( double beta_ = 0.25, double gamma_ = 0.5 )
inline

Definition at line 720 of file ode.hpp.

## ◆ Init()

 void mfem::NewmarkSolver::Init ( SecondOrderTimeDependentOperator & f )
overridevirtual

Associate a TimeDependentOperator with the ODE solver.

This method has to be called:

Reimplemented from mfem::SecondOrderODESolver.

Definition at line 995 of file ode.cpp.

## ◆ PrintProperties()

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

Definition at line 1003 of file ode.cpp.

## ◆ Step()

 void mfem::NewmarkSolver::Step ( Vector & x, Vector & dxdt, double & t, double & 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 1032 of file ode.cpp.

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