Description

Newmark constrained implicit for II order DAE systems.

#include <ChTimestepperImplicit.h>

Inheritance diagram for chrono::ChTimestepperNewmark:

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Collaboration diagram for chrono::ChTimestepperNewmark:

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Public Member Functions
	ChTimestepperNewmark (ChIntegrableIIorder *intgr=nullptr)

virtual Type	GetType () const override
	Return type of the integration method. More...

virtual ChIntegrable *	GetIntegrable () const override
	Return the associated integrable object.

void	SetGammaBeta (double gamma_val, double beta_val)
	Set the numerical damping parameter gamma and the beta parameter. More...

double	GetGamma () const

double	GetBeta () const

virtual void	OnAdvance (double dt) override
	Perform an integration step.

virtual void	ArchiveOut (ChArchiveOut &archive) override
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIn (ChArchiveIn &archive) override
	Method to allow de-serialization of transient data from archives.

Public Member Functions inherited from chrono::ChTimestepperIIorder
virtual ChState &	GetStatePos ()
	Access the state, position part, at current time.

virtual ChStateDelta &	GetStateVel ()
	Access the state, speed part, at current time.

virtual ChStateDelta &	GetStateAcc ()
	Access the acceleration, at current time.

virtual void	SetIntegrable (ChIntegrableIIorder *intgr)
	Set the integrable object.

ChIntegrableIIorder *	GetIntegrableIIorder () const
	Get the integrable object.

Public Member Functions inherited from chrono::ChTimestepperImplicit
void	SetMaxIters (int iters)
	Set the max number of Newton iterations.

void	SetRelTolerance (double rel_tol)
	Set the relative tolerance. More...

void	SetAbsTolerances (double abs_tolS, double abs_tolL)
	Set the absolute tolerances. More...

void	SetAbsTolerances (double abs_tol)
	Set the absolute tolerances. More...

void	SetJacobianUpdateMethod (JacobianUpdate method)
	Set the strategy for Jacobian update (default: EVERY_STEP).

double	GetMaxIters () const
	Get the max number of iterations using the Newton Raphson procedure.

JacobianUpdate	GetJacobianUpdateMethod () const
	Get the current Jacobian update startegy.

unsigned int	GetNumStepIterations () const
	Return the number of Newton iterations over the last step.

unsigned int	GetNumStepSetupCalls () const
	Return the number of calls to the solver's Setup function made during the last step.

unsigned int	GetNumStepSolveCalls () const
	Return the number of calls to the solver's Solve function made over the last step.

double	GetEstimatedConvergenceRate () const
	Get the last estimated convergence rate for the internal Newton solver. More...

unsigned int	GetNumIterations () const
	Return the cumulative number of Newton iterations.

unsigned int	GetNumSetupCalls () const
	Return the cummulative number of calls to the solver's Setup function.

unsigned int	GetNumSolveCalls () const
	Return the cumulative number of calls to the solver's Solve function.

void	AcceptTerminatedStep (bool accept)
	Accept step after a non-converged Newton solve (default: true). More...

unsigned int	GetNumTerminated () const
	Return the number of terminated Newton solves. More...

void	SetStepControl (bool enable)
	Turn on/off the internal step size control. More...

void	SetMinStepSize (double step)
	Set the minimum step size. More...

void	SetMaxItersSuccess (int iters)
	Set the maximum allowable number of iterations for counting a step towards a stepsize increase. More...

void	SetRequiredSuccessfulSteps (int num_steps)
	Set the minimum number of (internal) steps that use at most maxiters_success before considering a stepsize increase. More...

void	SetStepIncreaseFactor (double factor)
	Set the multiplicative factor for a stepsize increase (must be larger than 1). More...

void	SetStepDecreaseFactor (double factor)
	Set the multiplicative factor for a stepsize decrease (must be smaller than 1). More...

virtual void	Advance (double dt) override final
	Perform an integration step. More...

Public Member Functions inherited from chrono::ChTimestepper
virtual ChVectorDynamic &	GetLagrangeMultipliers ()
	Access the Lagrange multipliers, if any.

virtual double	GetTime () const
	Get the current time.

virtual void	SetTime (double mt)
	Set the current time.

void	SetVerbose (bool verb)
	Turn on/off logging of messages.

Additional Inherited Members
Public Types inherited from chrono::ChTimestepperImplicit
enum	JacobianUpdate { JacobianUpdate::EVERY_ITERATION, JacobianUpdate::EVERY_STEP, JacobianUpdate::NEVER, JacobianUpdate::AUTOMATIC }
	Newton Jacobian update strategies. More...

Public Types inherited from chrono::ChTimestepper
enum	Type { EULER_EXPLICIT_I, EULER_EXPLICIT_II, EULER_SEMI_IMPLICIT, RUNGE_KUTTA, HEUN, LEAPFROG, EULER_IMPLICIT, EULER_IMPLICIT_LINEARIZED, EULER_IMPLICIT_PROJECTED, TRAPEZOIDAL, TRAPEZOIDAL_LINEARIZED, NEWMARK, HHT, CUSTOM }
	Methods for time integration.

Static Public Member Functions inherited from chrono::ChTimestepperImplicit
static std::string	GetJacobianUpdateMethodAsString (JacobianUpdate jacobian_update)
	Return Jacobian update method as a string.

Static Public Member Functions inherited from chrono::ChTimestepper
static std::string	GetTypeAsString (Type type)
	Return the integrator type as a string.

Protected Member Functions inherited from chrono::ChTimestepperIIorder
	ChTimestepperIIorder (ChIntegrableIIorder *intgr=nullptr)

Protected Member Functions inherited from chrono::ChTimestepperImplicit
virtual void	InitializeStep ()
	Initialize integrator at beginning of a new step. More...

virtual void	PrepareStep ()
	Prepare integrator for attempting a new step. More...

virtual void	Increment ()
	Calculate new state increment for a Newton iteration. More...

virtual void	ResetStep ()
	Reset step data for re-attempting step (with new Jacobian or reduced step size). More...

virtual void	AcceptStep ()
	Accept attempted step (if Newton converged or was terminated). More...

virtual void	FinalizeStep ()
	Finalize step and update solution at end of step. More...

bool	CheckConvergence (int iteration)
	Check convergence of Newton process.

void	CalcErrorWeights (const ChVectorDynamic<> &x, double rtol, double atol, ChVectorDynamic<> &ewt)
	Calculate error weights based on the given state and tolerances.

Protected Member Functions inherited from chrono::ChTimestepper
	ChTimestepper (ChIntegrable *intgr=nullptr)

Protected Attributes inherited from chrono::ChTimestepperIIorder
ChIntegrableIIorder *	integrable

ChState	X

ChStateDelta	V

ChStateDelta	A

Protected Attributes inherited from chrono::ChTimestepperImplicit
JacobianUpdate	jacobian_update_method
	Jacobian update strategy.

bool	call_setup
	should the solver's Setup function be called?

bool	call_analyze
	should the solver's Setup analyze phase be called?

bool	jacobian_is_current
	was the Jacobian evaluated at current Newton iteration?

unsigned int	max_iters
	maximum number of iterations

double	reltol
	relative tolerance

double	abstolS
	absolute tolerance (states)

double	abstolL
	absolute tolerance (Lagrange multipliers)

unsigned int	num_step_iters
	number of iterations during last step

unsigned int	num_step_setups
	number of calls to the solver Setup() function during last step

unsigned int	num_step_solves
	number of calls to the solver Solve() function during last step

unsigned int	num_iters
	current cumulative number of Newton iterations

unsigned int	num_setups
	current cumulative number of Setup() calls

unsigned int	num_solves
	current cummulative number of Solve() calls

unsigned int	num_terminated
	number of terminated NEwton iterations

double	convergence_rate
	estimated Newton rate of convergence

ChStateDelta	Ds
	state update

ChVectorDynamic	Dl
	Lagrange multiplier update.

ChVectorDynamic	R
	residual of nonlinear system (dynamics portion)

ChVectorDynamic	Qc
	residual of nonlinear system (constraints portion)

std::array< double, 3 >	Ds_nrm_hist
	last 3 update norms

std::array< double, 3 >	Dl_nrm_hist
	last 3 update norms

ChVectorDynamic	ewtS
	vector of error weights (states)

ChVectorDynamic	ewtL
	vector of error weights (Lagrange multipliers)

bool	accept_terminated
	accept or reject steps after a non-converged Newton solve

bool	step_control
	step size control enabled?

unsigned int	maxiters_success
	maximum number of NR iterations to declare a step successful

unsigned int	req_successful_steps
	required number of successive successful steps for a stepsize increase

double	step_increase_factor
	factor used in increasing stepsize (>1)

double	step_decrease_factor
	factor used in decreasing stepsize (<1)

double	h_min
	minimum allowable stepsize

double	h
	internal stepsize

unsigned int	num_successful_steps
	number of successful steps

Protected Attributes inherited from chrono::ChTimestepper
bool	verbose

double	T

ChVectorDynamic	L

bool	Qc_do_clamp

double	Qc_clamping

Member Function Documentation

◆ GetType()

virtual Type chrono::ChTimestepperNewmark::GetType ( ) const

inlineoverridevirtual

Return type of the integration method.

Default is CUSTOM. Derived classes should override this function.

Implements chrono::ChTimestepper.

◆ SetGammaBeta()

void chrono::ChTimestepperNewmark::SetGammaBeta	(	double	gamma_val,
		double	beta_val
	)

Set the numerical damping parameter gamma and the beta parameter.

gamma: in the [1/2, 1] interval. gamma = 1/2, no numerical damping gamma > 1/2, more damping
beta: in the [0, 1] interval. beta = 1/4, gamma = 1/2 -> constant acceleration method beta = 1/6, gamma = 1/2 -> linear acceleration method Method is second order accurate only for gamma = 1/2.

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

/builds/uwsbel/chrono/src/chrono/timestepper/ChTimestepperImplicit.h
/builds/uwsbel/chrono/src/chrono/timestepper/ChTimestepperImplicit.cpp

Description

Public Member Functions

Additional Inherited Members

Member Function Documentation

◆ GetType()

◆ SetGammaBeta()