Module implementing Milne's device predictor-corrector method. More...

#include "MilneDeviceModule.h"

Inheritance diagram for MilneDeviceModule:

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Collaboration diagram for MilneDeviceModule:

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Public Member Functions
	MilneDeviceModule (const String &name="MilneDevice")
	Constructor.

virtual void	solve (const Properties &info, const Properties &globdat) override
	Solve using Milne's device predictor-corrector method.

virtual	~MilneDeviceModule ()
	Destructor.

Public Member Functions inherited from ExplicitModule
virtual Status	init (const Properties &conf, const Properties &props, const Properties &globdat) override
	Initialize the module.

virtual void	shutdown (const Properties &globdat) override
	Shutdown the module.

virtual void	configure (const Properties &props, const Properties &globdat) override
	Configure the module from properties.

virtual void	getConfig (const Properties &props, const Properties &globdat) const override
	Get current module configuration.

virtual void	advance (const Properties &globdat) override
	Advance to next time step.

virtual void	cancel (const Properties &globdat) override
	Cancel current solution attempt.

virtual bool	commit (const Properties &globdat) override
	Compute next step size and commit solution.

virtual void	setPrecision (double eps) override
	Set convergence precision.

virtual double	getPrecision () const override
	Get current convergence precision.

Static Public Member Functions
static Ref< Module >	makeNew (const String &name, const Properties &conf, const Properties &props, const Properties &globdat)
	Factory method for creating new MilneDeviceModule instances.

static void	declare ()
	Register MilneDeviceModule type with ModuleFactory.

Static Public Attributes
Property identifiers
static const char *	TYPE_NAME = "MilneDevice"
	Module type name.

Static Public Attributes inherited from ExplicitModule
static const char *	TYPE_NAME = "Explicit"
	Module type name.

static const char *	STEP_COUNT = "stepCount"
	Step count property.

static const char *	SO3_DOFS = "dofs_SO3"
	SO(3) DOF types property.

static const char *	LEN_SCALE = "lengthScale"
	Length scale property.

static const char *	MASS_MATRIX = "explicitMass"
	globdat key of the published mass matrix

Protected Member Functions
Vector	updForce (const Vector &fint, const Vector &fext, const Properties &globdat)
	Update forces for corrector step.

Protected Member Functions inherited from ExplicitModule
	ExplicitModule (const String &name="")
	Protected constructor.

virtual	~ExplicitModule ()
	Protected destructor.

void	updateMass_ (const Properties &globdat)
	Update mass matrix.

void	invalidate_ ()
	invalidate_ current state

void	evalCommittedForce_ (const Properties &globdat)
	Evaluate the internal force at the committed state.

void	publishCommittedForce_ (const Properties &globdat)
	Publish the internal force of the committed state in globdat Not compatible with TangentOutputModule. With a consistent mass a reference to the mass matrix of the finished step is published as well (MASS_MATRIX), so that output modules can evaluate the gyroscopic force on demand (GET_GYRO_VECTOR); the solver itself does not use it.

void	dropCommittedForce_ (const Properties &globdat)
	Remove the published forces again (they are no longer valid)

void	updRotMask_ ()
	Rebuild the rotational DOF mask from rdofs_.

void	ABupdate (const Vector &delta_y, const Vector &f_cur, const Vector &f_old) const
	Adams-Bashforth 2-step update.

void	ABupdate (const Vector &delta_y, const Vector &f_cur) const
	Adams-Bashforth 1-step update (explicit Euler)

void	updateVec (const Vector &y_new, const Vector &y_old, const Vector &delta_y, const bool rot=false)
	Update displacement vectors with optional SO(3) handling.

void	getAcce (const Vector &a, const Ref< Constraints > &cons, const Vector &fres, const Properties &globdat)
	Get acceleration and return resulting force vector.

Vector	getForce (const Vector &fint, const Vector &fext, const Properties &globdat)
	Get force vector.

double	getQuality (const Vector &y_pre, const Vector &y_cor)
	Get solution quality measure.

Additional Inherited Members
Public Types inherited from ExplicitModule
enum	MassMode { LUMPED , CONSISTENT }
	Mass matrix formulation modes. More...

Protected Attributes inherited from ExplicitModule
bool	valid_
	State validity flag.

bool	fintCacheValid_
	True between commit and the next state change.

Vector	fintCache_
	Internal force (without gyroscopic term) at the committed state.

Vector	fintCacheDisp_
	Displacements the cached force belongs to.

double	dtime_
	Current time step size.

double	prec_
	Precision tolerance.

double	minDtime_
	Minimum time step size.

double	maxDtime_
	Maximum time step size.

double	saftey_
	Safety factor for step size control.

double	incrFact_
	Step size increase factor.

double	decrFact_
	Step size decrease factor.

MassMode	mode_
	Mass matrix mode.

idx_t	order_
	Integration order.

double	lenScale_
	Characteristic length scale.

Ref< Function >	updCond_
	Update condition function.

Vector	massInv_
	Inverse mass matrix.

IdxVector	dofsSO3_
	SO(3) DOF type indices.

IdxMatrix	rdofs_
	Rotational DOF mapping.

BoolVector	isRotDof_
	Mask of rotational DOFs (rebuilt with rdofs_)

Ref< Model >	model_
	Root of the model tree.

Ref< DofSpace >	dofs_
	Degree of freedom space.

Ref< Constraints >	cons_
	Constraint manager.

Ref< Solver >	solver_
	Linear solver.

Detailed Description

This module implements Milne's device, a predictor-corrector scheme that combines Adams-Bashforth predictor steps with Adams-Moulton corrector steps for explicit time integration. The method proceeds in three phases:

Predictor step: Uses Adams-Bashforth method to predict state at next time
Corrector step: Uses Adams-Moulton method to correct the prediction
Step size adaptation: Evaluates solution quality for potential step size control

The predictor-corrector approach provides better stability and accuracy compared to simple explicit methods while maintaining computational efficiency. The module supports both first-order (Euler implicit) and second-order (trapezoidal rule) Adams-Moulton correctors.

See also: Milne (1926)

Constructor & Destructor Documentation

◆ MilneDeviceModule()

MilneDeviceModule::MilneDeviceModule ( const String & name = "MilneDevice" )

explicit

Parameters

[in] name Module name (default: "MilneDevice")

◆ ~MilneDeviceModule()

MilneDeviceModule::~MilneDeviceModule ( )

virtual

Member Function Documentation

◆ declare()

void MilneDeviceModule::declare ( )

static

◆ makeNew()

Ref< Module > MilneDeviceModule::makeNew	(	const String &	name,
		const Properties &	conf,
		const Properties &	props,
		const Properties &	globdat
	)

static

Parameters

[in]	name	Module name
[out]	conf	Actually used configuration properties (output)
[in]	props	User-specified module properties
[in]	globdat	Global data container

Returns: Reference to new MilneDeviceModule instance

◆ solve()

void MilneDeviceModule::solve	(	const Properties &	info,
		const Properties &	globdat
	)

overridevirtual

Parameters

[out]	info	Solver information (output)
[in]	globdat	Global data container

Performs one time step using predictor-corrector algorithm:

Predict velocities and displacements using Adams-Bashforth
Correct using Adams-Moulton with updated forces
Evaluate solution quality for step size adaptation

Implements ExplicitModule.

◆ updForce()

Vector MilneDeviceModule::updForce	(	const Vector &	fint,
		const Vector &	fext,
		const Properties &	globdat
	)

protected

Parameters

[in,out]	fint	Internal force vector, modified in place
[in]	fext	External force vector
[in]	globdat	Global data container

Returns: Resulting force vector (external - internal)

In the corrector step, only internal forces change due to updated displacement field, so external forces remain constant

Member Data Documentation

◆ TYPE_NAME

const char * MilneDeviceModule::TYPE_NAME = "MilneDevice"

static

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MilneDeviceModule()

◆ ~MilneDeviceModule()

Member Function Documentation

◆ declare()

◆ makeNew()

◆ solve()

◆ updForce()

Member Data Documentation

◆ TYPE_NAME