Description

Physics element that carries its own dynamics, described as an index-3 DAE IVP of the form:

  M * y'' + (Cy)^T * lambda = F
  C(y) = 0
  y(t0) = y0
  y'(t0) = yd0

The internal states are integrated simultaneously with the containing system and they can be accessed and coupled with other physics elements.

#include <ChExternalDynamicsDAE.h>

Inheritance diagram for chrono::ChExternalDynamicsDAE:

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Collaboration diagram for chrono::ChExternalDynamicsDAE:

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Public Member Functions
virtual void	Initialize ()
	Initialize the physics item.

virtual bool	InExplicitForm () const
	Declare as explicit form (identity mass matrix). More...

virtual bool	IsStiff () const
	Declare as stiff (default: false). More...

virtual bool	IsRheonomous () const
	Declare the DAE as rheonomous (default: false). More...

virtual unsigned int	GetNumStates () const =0
	Get number of states (dimension of y).

virtual unsigned int	GetNumStateDerivatives () const
	Get number of state derivatives (dimension of yd). More...

virtual unsigned int	GetNumAlgebraicConstraints () const
	Get number of algebraic constraints.

ChVectorDynamic	GetInitialStates ()
	Get the initial state values (state at initial time).

ChVectorDynamic	GetInitialStateDerivatives ()
	Get the initial state derivative values (state derivatives at initial time).

const ChVectorDynamic &	GetStates () const
	Get current states.

const ChVectorDynamic &	GetStateDerivatives () const
	Get current state derivatives.

const ChVectorDynamic &	GetForce () const
	Get current applied force.

Public Member Functions inherited from chrono::ChPhysicsItem
	ChPhysicsItem (const ChPhysicsItem &other)

virtual ChPhysicsItem *	Clone () const override
	"Virtual" copy constructor (covariant return type).

ChSystem *	GetSystem () const
	Get the pointer to the parent ChSystem().

virtual void	SetSystem (ChSystem *m_system)
	Set the pointer to the parent ChSystem(). More...

void	AddVisualModel (std::shared_ptr< ChVisualModel > model)
	Add an (optional) visualization model. More...

std::shared_ptr< ChVisualModel >	GetVisualModel () const
	Access the visualization model (if any). More...

void	AddVisualShape (std::shared_ptr< ChVisualShape > shape, const ChFrame<> &frame=ChFrame<>())
	Add the specified visual shape to the visualization model. More...

std::shared_ptr< ChVisualShape >	GetVisualShape (unsigned int i) const
	Access the specified visualization shape in the visualization model (if any). More...

void	AddVisualShapeFEA (std::shared_ptr< ChVisualShapeFEA > shapeFEA)
	Add the specified FEA visualization object to the visualization model. More...

std::shared_ptr< ChVisualShapeFEA >	GetVisualShapeFEA (unsigned int i) const
	Access the specified FEA visualization object in the visualization model (if any). More...

virtual ChFrame	GetVisualModelFrame (unsigned int nclone=0) const
	Get the reference frame (expressed in and relative to the absolute frame) of the visual model. More...

virtual unsigned int	GetNumVisualModelClones () const
	Return the number of clones of the visual model associated with this physics item. More...

void	AddCamera (std::shared_ptr< ChCamera > camera)
	Attach a ChCamera to this physical item. More...

std::vector< std::shared_ptr< ChCamera > >	GetCameras () const
	Get the set of cameras attached to this physics item.

virtual bool	IsActive () const
	Return true if the object is active and included in dynamics.

virtual bool	IsCollisionEnabled () const
	Tell if the object is subject to collision. More...

virtual void	AddCollisionModelsToSystem (ChCollisionSystem *coll_sys) const
	Add to the provided collision system any collision models managed by this physics item. More...

virtual void	RemoveCollisionModelsFromSystem (ChCollisionSystem *coll_sys) const
	Remove from the provided collision system any collision models managed by this physics item. More...

virtual void	SyncCollisionModels ()
	Synchronize the position and bounding box of any collsion models managed by this physics item.

virtual ChAABB	GetTotalAABB () const
	Get the axis-aligned bounding box (AABB) of this object. More...

virtual ChVector3d	GetCenter () const
	Get a symbolic 'center' of the object. More...

virtual void	Setup ()
	Perform setup operations. More...

virtual void	Update (bool update_assets=true)
	Perform an update using the current time.

void	UpdateVisualModel ()
	Utility function to update only the associated visual assets (if any).

virtual void	ForceToRest ()
	Set zero speed (and zero accelerations) in state, without changing the position. More...

virtual unsigned int	GetNumConstraintsUnilateral ()
	Get the number of unilateral scalar constraints.

unsigned int	GetOffset_x ()
	Get offset in the state vector (position part)

unsigned int	GetOffset_w ()
	Get offset in the state vector (speed part)

unsigned int	GetOffset_L ()
	Get offset in the lagrangian multipliers.

void	SetOffset_x (const unsigned int moff)
	Set offset in the state vector (position part) Note: only the ChSystem::Setup function should use this.

void	SetOffset_w (const unsigned int moff)
	Set offset in the state vector (speed part) Note: only the ChSystem::Setup function should use this.

void	SetOffset_L (const unsigned int moff)
	Set offset in the lagrangian multipliers Note: only the ChSystem::Setup function should use this.

virtual void	VariablesFbReset ()
	Sets the 'fb' part (the known term) of the encapsulated ChVariables to zero.

virtual void	VariablesFbLoadForces (double factor=1)
	Adds the current forces (applied to item) into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor.

virtual void	VariablesQbLoadSpeed ()
	Initialize the 'qb' part of the ChVariables with the current value of speeds. More...

virtual void	VariablesFbIncrementMq ()
	Adds M*q (masses multiplied current 'qb') to Fb, ex. More...

virtual void	VariablesQbSetSpeed (double step=0)
	Fetches the item speed (ex. More...

virtual void	VariablesQbIncrementPosition (double step)
	Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor. More...

virtual void	ConstraintsBiReset ()
	Sets to zero the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_C (double factor=1, double recovery_clamp=0.1, bool do_clamp=false)
	Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_Ct (double factor=1)
	Adds the current Ct (partial t-derivative, as in C_dt=0-> [Cq]*q_dt=-Ct) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_Qc (double factor=1)
	Adds the current Qc (the vector of C_dtdt=0 -> [Cq]*q_dtdt=Qc ) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsFbLoadForces (double factor=1)
	Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints.

virtual void	ConstraintsFetch_react (double factor=1)
	Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...

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

virtual void	ArchiveIn (ChArchiveIn &archive_in) override
	Method to allow deserialization of transient data from archives. More...

Public Member Functions inherited from chrono::ChObj
	ChObj (const ChObj &other)

int	GetIdentifier () const
	Get the unique integer identifier of this object. More...

void	SetTag (int tag)
	Set an object integer tag (default: -1). More...

int	GetTag () const
	Get the tag of this object.

void	SetName (const std::string &myname)
	Set the name of this object.

const std::string &	GetName () const
	Get the name of this object.

double	GetChTime () const
	Gets the simulation time of this object.

void	SetChTime (double m_time)
	Sets the simulation time of this object.

virtual std::string &	ArchiveContainerName ()

Protected Member Functions
virtual void	SetInitialConditions (ChVectorDynamic<> &y0, ChVectorDynamic<> &yd0)=0
	Set initial conditions. More...

virtual void	CalculateMassMatrix (ChMatrixDynamic<> &M)
	Calculate and return mass matrix. More...

virtual bool	CalculateMassTimesVector (const ChVectorDynamic<> &v, ChVectorDynamic<> &Mv)
	Calculate and return the product of the mass matrix and the given vector. More...

virtual void	CalculateForce (double time, const ChVectorDynamic<> &y, const ChVectorDynamic<> &yd, ChVectorDynamic<> &F)=0
	Calculate and return the generalized force (right-hand side) at the provided time and states. More...

virtual bool	CalculateForceJacobians (double time, const ChVectorDynamic<> &y, const ChVectorDynamic<> &yd, const ChVectorDynamic<> &F, double alpha, double beta, ChMatrixDynamic<> &J)
	Calculate a linear combination of the Jacobians of the generalized force with respect to the DAE states. More...

virtual void	CalculateConstraintViolation (double time, const ChVectorDynamic<> &y, ChVectorDynamic<> &c)
	Calculate the constraint violations c. More...

virtual bool	CalculateConstraintDerivative (double time, const ChVectorDynamic<> &y, const ChVectorDynamic<> &c, ChVectorDynamic<> &ct)
	Calculate the constraint violation partial derivative with respect to time. More...

virtual void	CalculateConstraintJacobian (double time, const ChVectorDynamic<> &y, const ChVectorDynamic<> &c, ChMatrixDynamic<> &J)
	Calculate the Jacobian of the constraints with respect to the DAE states. More...

virtual void	IncrementState (const ChVectorDynamic<> &x, const ChVectorDynamic<> &Dv, ChVectorDynamic<> &x_new)
	Increment the state vector by the provided vector. More...

virtual void	CalculateStateIncrement (const ChVectorDynamic<> &x, const ChVectorDynamic<> &x_new, ChVectorDynamic<> &Dv)
	Calculate the increment between the two procided state vectors. More...

virtual void	OnUpdate (double time, const ChVectorDynamic<> &y, const ChVectorDynamic<> &yd)
	Optional operations performed before an update. More...

virtual void	Update (double time, bool update_assets=true) override
	Perform any updates necessary at the current phase during the solution process. More...

virtual unsigned int	GetNumCoordsPosLevel () override
	Get the number of coordinates at the position level. More...

virtual unsigned int	GetNumCoordsVelLevel () override
	Get the number of coordinates at the velocity level. More...

virtual unsigned int	GetNumConstraints () override
	Get the number of scalar constraints.

virtual unsigned int	GetNumConstraintsBilateral () override
	Get the number of bilateral scalar constraints.

virtual void	InjectVariables (ChSystemDescriptor &descriptor) override
	Register with the given system descriptor any ChVariable objects associated with this item.

virtual void	InjectConstraints (ChSystemDescriptor &descriptor) override
	Register with the given system descriptor any ChConstraint objects associated with this item.

virtual void	InjectKRMMatrices (ChSystemDescriptor &descriptor) override
	Register with the given system descriptor any ChKRMBlock objects associated with this item.

virtual void	IntStateGather (const unsigned int off_x, ChState &x, const unsigned int off_v, ChStateDelta &v, double &T) override
	From item's state to global state vectors y={x,v} pasting the states at the specified offsets. More...

virtual void	IntStateScatter (const unsigned int off_x, const ChState &x, const unsigned int off_v, const ChStateDelta &v, const double T, bool full_update) override
	From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets. More...

virtual void	IntStateGatherAcceleration (const unsigned int off_a, ChStateDelta &a) override
	From item's state acceleration to global acceleration vector. More...

virtual void	IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a) override
	From global acceleration vector to item's state acceleration. More...

virtual void	IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L) override
	From item's reaction forces to global reaction vector. More...

virtual void	IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L) override
	From global reaction vector to item's reaction forces. More...

virtual void	IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv) override
	Computes x_new = x + Dt , using vectors at specified offsets. More...

virtual void	IntStateGetIncrement (const unsigned int off_x, const ChState &x_new, const ChState &x, const unsigned int off_v, ChStateDelta &Dv) override
	Computes Dt = x_new - x, using vectors at specified offsets. More...

virtual void	IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c) override
	Takes the F force term, scale and adds to R at given offset: R += c*F. More...

virtual void	IntLoadResidual_Mv (const unsigned int off, ChVectorDynamic<> &R, const ChVectorDynamic<> &v, const double c) override
	Takes the Mv term, multiplying mass by a vector, scale and adds to R at given offset: R += cM*w. More...

virtual void	IntLoadLumpedMass_Md (const unsigned int off, ChVectorDynamic<> &Md, double &err, const double c) override
	Adds the lumped mass to a Md vector, representing a mass diagonal matrix. More...

virtual void	IntLoadConstraint_C (const unsigned int off, ChVectorDynamic<> &Qc, const double c, bool do_clamp, double recovery_clamp) override
	Takes the term C, scale and adds to Qc at given offset: Qc += c*C. More...

virtual void	IntLoadConstraint_Ct (const unsigned int off, ChVectorDynamic<> &Qc, const double c) override
	Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...

virtual void	IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c) override
	Takes the term Cq'L, scale and adds to R at given offset: R += cCq'*L. More...

virtual void	IntToDescriptor (const unsigned int off_v, const ChStateDelta &v, const ChVectorDynamic<> &R, const unsigned int off_L, const ChVectorDynamic<> &L, const ChVectorDynamic<> &Qc) override
	Prepare variables and constraints to accommodate a solution: More...

virtual void	IntFromDescriptor (const unsigned int off_v, ChStateDelta &v, const unsigned int off_L, ChVectorDynamic<> &L) override
	After a solver solution, fetch values from variables and constraints into vectors: More...

virtual void	LoadConstraintJacobians () override
	Compute and load current Jacobians in encapsulated ChConstraint objects.

virtual void	LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor) override
	Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More...

Protected Member Functions inherited from chrono::ChObj
int	GenerateUniqueIdentifier ()

Additional Inherited Members
Protected Attributes inherited from chrono::ChPhysicsItem
ChSystem *	system
	parent system

std::shared_ptr< ChVisualModelInstance >	vis_model_instance
	instantiated visualization model

std::vector< std::shared_ptr< ChCamera > >	cameras
	set of cameras

unsigned int	offset_x
	offset in vector of state (position part)

unsigned int	offset_w
	offset in vector of state (speed part)

unsigned int	offset_L
	offset in vector of lagrangian multipliers

Protected Attributes inherited from chrono::ChObj
double	ChTime
	object simulation time

std::string	m_name
	object name

int	m_identifier
	object unique identifier

int	m_tag
	user-supplied tag

Member Function Documentation

◆ CalculateConstraintDerivative()

virtual bool chrono::ChExternalDynamicsDAE::CalculateConstraintDerivative	(	double	time,
		const ChVectorDynamic<> &	y,
		const ChVectorDynamic<> &	c,
		ChVectorDynamic<> &	ct
	)

inlineprotectedvirtual

Calculate the constraint violation partial derivative with respect to time.

Must load ct = \partial c / \partial t, for c = c(t,y). This function is optional and only used is the system is rheonomous. If provided, load the constraint derivatives in the provided vector 'c' and return 'true'. In that case, this overrides the default finite difference approximation.

Parameters

time	current time
y	current DAE states
c	current constraint violations
ct	output constraint derivative vector

◆ CalculateConstraintJacobian()

virtual void chrono::ChExternalDynamicsDAE::CalculateConstraintJacobian	(	double	time,
		const ChVectorDynamic<> &	y,
		const ChVectorDynamic<> &	c,
		ChMatrixDynamic<> &	J
	)

inlineprotectedvirtual

Calculate the Jacobian of the constraints with respect to the DAE states.

Parameters

time	current time
y	current DAE states
c	current constraint violations
J	output Jacobian matrix

◆ CalculateConstraintViolation()

virtual void chrono::ChExternalDynamicsDAE::CalculateConstraintViolation	(	double	time,
		const ChVectorDynamic<> &	y,
		ChVectorDynamic<> &	c
	)

inlineprotectedvirtual

Calculate the constraint violations c.

Parameters

time	current time
y	current DAE states
c	output constraint violation vector

◆ CalculateForce()

virtual void chrono::ChExternalDynamicsDAE::CalculateForce	(	double	time,
		const ChVectorDynamic<> &	y,
		const ChVectorDynamic<> &	yd,
		ChVectorDynamic<> &	F
	)

protectedpure virtual

Calculate and return the generalized force (right-hand side) at the provided time and states.

Must load F = F(t,y, yd).

Parameters

time	current time
y	current DAE states
yd	current DAE state derivatives
F	output right-hand side force vector

◆ CalculateForceJacobians()

virtual bool chrono::ChExternalDynamicsDAE::CalculateForceJacobians	(	double	time,
		const ChVectorDynamic<> &	y,
		const ChVectorDynamic<> &	yd,
		const ChVectorDynamic<> &	F,
		double	alpha,
		double	beta,
		ChMatrixDynamic<> &	J
	)

inlineprotectedvirtual

Calculate a linear combination of the Jacobians of the generalized force with respect to the DAE states.

Must load J = alpha * dF/dy + beta * dF/dyd, for given alpha and beta. Only used if the physics item is declared as stiff. If provided, load J into the provided matrix 'J' (already set to zero before the call) and return 'true'. In that case, the user-provided Jacobian will overwrite the default finite-difference approximation. Note that a derived class must always implement CalculateForceJacobians if the number of derivatives and states are different.

Parameters

time	current time
y	current DAE states
yd	current DAE state derivatives
F	current right-hand side force vector
alpha	multiplier for Jacobian wrt y
beta	multiplier for Jacobian wrt yd
J	output Jacobian matrix

◆ CalculateMassMatrix()

virtual void chrono::ChExternalDynamicsDAE::CalculateMassMatrix ( ChMatrixDynamic<> & M )

inlineprotectedvirtual

Calculate and return mass matrix.

This function must be implemented if the DAE is in implicit form.

◆ CalculateMassTimesVector()

virtual bool chrono::ChExternalDynamicsDAE::CalculateMassTimesVector	(	const ChVectorDynamic<> &	v,
		ChVectorDynamic<> &	Mv
	)

inlineprotectedvirtual

Calculate and return the product of the mass matrix and the given vector.

This function is optional and is used only if the DAE is declared in implicit form. If provided, calculate M*v in the provided vector 'Mv' and return 'true'. In that case, this overwrites the default matrix-vector product calculation.

◆ CalculateStateIncrement()

virtual void chrono::ChExternalDynamicsDAE::CalculateStateIncrement	(	const ChVectorDynamic<> &	x,
		const ChVectorDynamic<> &	x_new,
		ChVectorDynamic<> &	Dv
	)

inlineprotectedvirtual

Calculate the increment between the two procided state vectors.

Must calculate Dv = x_new - x. If the number of derivatives is equal to the number of states, this is a simple vector subtraction and this function need not be implemented. Otherwise (e.g., when using quaternions for rotations), special treatment is required and a derived class must provide an override. Here, 'x' and 'x_new' are vectors of length Ny, and 'Dv' has length Nyd.

◆ GetNumCoordsPosLevel()

virtual unsigned int chrono::ChExternalDynamicsDAE::GetNumCoordsPosLevel ( )

inlineoverrideprotectedvirtual

Get the number of coordinates at the position level.

Might differ from coordinates at velocity level if quaternions are used for rotations.

Reimplemented from chrono::ChPhysicsItem.

◆ GetNumCoordsVelLevel()

virtual unsigned int chrono::ChExternalDynamicsDAE::GetNumCoordsVelLevel ( )

inlineoverrideprotectedvirtual

Get the number of coordinates at the velocity level.

Might differ from coordinates at position level if quaternions are used for rotations.

Reimplemented from chrono::ChPhysicsItem.

◆ GetNumStateDerivatives()

virtual unsigned int chrono::ChExternalDynamicsDAE::GetNumStateDerivatives ( ) const

inlinevirtual

Get number of state derivatives (dimension of yd).

The default implementation assumes equal number of states and state derivatives. If this is not the case, a derived class must implement the functions IncrementState, CalculateStateIncrement, and (if stiff) CalculateForceJacobians.

◆ IncrementState()

virtual void chrono::ChExternalDynamicsDAE::IncrementState	(	const ChVectorDynamic<> &	x,
		const ChVectorDynamic<> &	Dv,
		ChVectorDynamic<> &	x_new
	)

inlineprotectedvirtual

Increment the state vector by the provided vector.

Must calculate x_new = x + Dv. If the number of derivatives is equal to the number of states, this is a simple vector addition and this function need not be implemented. Otherwise (e.g., when using quaternions for rotations), special treatment is required and a derived class must provide an override. Here, 'x' and 'x_new' are vectors of length Ny, and 'Dv' has length Nyd.

◆ InExplicitForm()

virtual bool chrono::ChExternalDynamicsDAE::InExplicitForm ( ) const

inlinevirtual

Declare as explicit form (identity mass matrix).

If not in explicit form, a derived class must implement the function CalculateMassMatrix and optionally CalculateMassTimesVector.

◆ IntFromDescriptor()

void chrono::ChExternalDynamicsDAE::IntFromDescriptor	(	const unsigned int	off_v,
		ChStateDelta &	v,
		const unsigned int	off_L,
		ChVectorDynamic<> &	L
	)

overrideprotectedvirtual

After a solver solution, fetch values from variables and constraints into vectors:

Parameters

off_v	offset for v
v	vector to where the q 'unknowns' term of the variables will be copied
off_L	offset for L
L	vector to where L 'lagrangian ' term of the constraints will be copied

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadConstraint_C()

void chrono::ChExternalDynamicsDAE::IntLoadConstraint_C	(	const unsigned int	off,
		ChVectorDynamic<> &	Qc,
		const double	c,
		bool	do_clamp,
		double	recovery_clamp
	)

overrideprotectedvirtual

Takes the term C, scale and adds to Qc at given offset: Qc += c*C.

Parameters

off	offset in Qc residual
Qc	result: the Qc residual, Qc += c*C
c	a scaling factor
do_clamp	apply clamping to c*C?
recovery_clamp	value for min/max clamping of c*C

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadConstraint_Ct()

void chrono::ChExternalDynamicsDAE::IntLoadConstraint_Ct	(	const unsigned int	off,
		ChVectorDynamic<> &	Qc,
		const double	c
	)

overrideprotectedvirtual

Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct.

Parameters

off	offset in Qc residual
Qc	result: the Qc residual, Qc += c*Ct
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadLumpedMass_Md()

void chrono::ChExternalDynamicsDAE::IntLoadLumpedMass_Md	(	const unsigned int	off,
		ChVectorDynamic<> &	Md,
		double &	err,
		const double	c
	)

overrideprotectedvirtual

Adds the lumped mass to a Md vector, representing a mass diagonal matrix.

Used by lumped explicit integrators. If mass lumping is impossible or approximate, adds scalar error to "error" parameter. Md += c*diag(M)

Parameters

off	offset in Md vector
Md	result: Md vector, diagonal of the lumped mass matrix
err	result: not touched if lumping does not introduce errors
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadResidual_CqL()

void chrono::ChExternalDynamicsDAE::IntLoadResidual_CqL	(	const unsigned int	off_L,
		ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	L,
		const double	c
	)

overrideprotectedvirtual

Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L.

Parameters

off_L	offset in L multipliers
R	result: the R residual, R += cCq'L
L	the L vector
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadResidual_F()

void chrono::ChExternalDynamicsDAE::IntLoadResidual_F	(	const unsigned int	off,
		ChVectorDynamic<> &	R,
		const double	c
	)

overrideprotectedvirtual

Takes the F force term, scale and adds to R at given offset: R += c*F.

Parameters

off	offset in R residual
R	result: the R residual, R += c*F
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadResidual_Mv()

void chrono::ChExternalDynamicsDAE::IntLoadResidual_Mv	(	const unsigned int	off,
		ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	w,
		const double	c
	)

overrideprotectedvirtual

Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w.

Parameters

off	offset in R residual
R	result: the R residual, R += cMv
w	the w vector
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGather()

void chrono::ChExternalDynamicsDAE::IntStateGather	(	const unsigned int	off_x,
		ChState &	x,
		const unsigned int	off_v,
		ChStateDelta &	v,
		double &	T
	)

overrideprotectedvirtual

From item's state to global state vectors y={x,v} pasting the states at the specified offsets.

Parameters

off_x	offset in x state vector
x	state vector, position part
off_v	offset in v state vector
v	state vector, speed part
T	time

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGatherAcceleration()

void chrono::ChExternalDynamicsDAE::IntStateGatherAcceleration	(	const unsigned int	off_a,
		ChStateDelta &	a
	)

overrideprotectedvirtual

From item's state acceleration to global acceleration vector.

Parameters

off_a	offset in a accel. vector
a	acceleration part of state vector derivative

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGatherReactions()

void chrono::ChExternalDynamicsDAE::IntStateGatherReactions	(	const unsigned int	off_L,
		ChVectorDynamic<> &	L
	)

overrideprotectedvirtual

From item's reaction forces to global reaction vector.

Parameters

off_L	offset in L vector
L	L vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGetIncrement()

void chrono::ChExternalDynamicsDAE::IntStateGetIncrement	(	const unsigned int	off_x,
		const ChState &	x_new,
		const ChState &	x,
		const unsigned int	off_v,
		ChStateDelta &	Dv
	)

overrideprotectedvirtual

Computes Dt = x_new - x, using vectors at specified offsets.

By default, when DOF = DOF_w, it does just the difference of two state vectors, but in some cases (ex when using quaternions for rotations) it could do more complex stuff, and children classes might overload it.

Parameters

off_x	offset in x state vector
x_new	state vector, final position part
x	state vector, initial position part
off_v	offset in v state vector
Dv	state vector, increment. Here gets the result

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateIncrement()

void chrono::ChExternalDynamicsDAE::IntStateIncrement	(	const unsigned int	off_x,
		ChState &	x_new,
		const ChState &	x,
		const unsigned int	off_v,
		const ChStateDelta &	Dv
	)

overrideprotectedvirtual

Computes x_new = x + Dt , using vectors at specified offsets.

By default, when DOF = DOF_w, it does just the sum, but in some cases (ex when using quaternions for rotations) it could do more complex stuff, and children classes might overload it.

Parameters

off_x	offset in x state vector
x_new	state vector, position part, incremented result
x	state vector, initial position part
off_v	offset in v state vector
Dv	state vector, increment

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateScatter()

void chrono::ChExternalDynamicsDAE::IntStateScatter	(	const unsigned int	off_x,
		const ChState &	x,
		const unsigned int	off_v,
		const ChStateDelta &	v,
		const double	T,
		bool	full_update
	)

overrideprotectedvirtual

From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets.

Parameters

off_x	offset in x state vector
x	state vector, position part
off_v	offset in v state vector
v	state vector, speed part
T	time
full_update	perform complete update

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateScatterAcceleration()

void chrono::ChExternalDynamicsDAE::IntStateScatterAcceleration	(	const unsigned int	off_a,
		const ChStateDelta &	a
	)

overrideprotectedvirtual

From global acceleration vector to item's state acceleration.

Parameters

off_a	offset in a accel. vector
a	acceleration part of state vector derivative

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateScatterReactions()

void chrono::ChExternalDynamicsDAE::IntStateScatterReactions	(	const unsigned int	off_L,
		const ChVectorDynamic<> &	L
	)

overrideprotectedvirtual

From global reaction vector to item's reaction forces.

Parameters

off_L	offset in L vector
L	L vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

◆ IntToDescriptor()

void chrono::ChExternalDynamicsDAE::IntToDescriptor	(	const unsigned int	off_v,
		const ChStateDelta &	v,
		const ChVectorDynamic<> &	R,
		const unsigned int	off_L,
		const ChVectorDynamic<> &	L,
		const ChVectorDynamic<> &	Qc
	)

overrideprotectedvirtual

Prepare variables and constraints to accommodate a solution:

Parameters

off_v	offset for v and R
v	vector copied into the q 'unknowns' term of the variables
R	vector copied into the F 'force' term of the variables
off_L	offset for L and Qc
L	vector copied into the L 'lagrangian ' term of the constraints
Qc	vector copied into the Qb 'constraint' term of the constraints

Reimplemented from chrono::ChPhysicsItem.

◆ IsRheonomous()

virtual bool chrono::ChExternalDynamicsDAE::IsRheonomous ( ) const

inlinevirtual

Declare the DAE as rheonomous (default: false).

A rheonomous system has constraints that depend explicitly on time.

◆ IsStiff()

virtual bool chrono::ChExternalDynamicsDAE::IsStiff ( ) const

inlinevirtual

Declare as stiff (default: false).

If stiff, Jacobian information will be generated.

◆ LoadKRMMatrices()

void chrono::ChExternalDynamicsDAE::LoadKRMMatrices	(	double	Kfactor,
		double	Rfactor,
		double	Mfactor
	)

overrideprotectedvirtual

Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects.

The resulting KRM blocks represent linear combinations of the K, R, and M matrices, with the specified coefficients Kfactor, Rfactor,and Mfactor, respectively. Note: signs are flipped from the term dF/dx in the integrator: K = -dF/dq and R = -dF/dv.

Reimplemented from chrono::ChPhysicsItem.

◆ OnUpdate()

virtual void chrono::ChExternalDynamicsDAE::OnUpdate	(	double	time,
		const ChVectorDynamic<> &	y,
		const ChVectorDynamic<> &	yd
	)

inlineprotectedvirtual

Optional operations performed before an update.

This function is invoked before calls to CalculateForce, CalculateConstraintViolation, and CalculateConstraintJacobian.

Parameters

time	current time
y	current DAE states
yd	current DAE state derivatives

◆ SetInitialConditions()

virtual void chrono::ChExternalDynamicsDAE::SetInitialConditions	(	ChVectorDynamic<> &	y0,
		ChVectorDynamic<> &	yd0
	)

protectedpure virtual

Set initial conditions.

Must load y0 = y(0).

◆ Update()

void chrono::ChExternalDynamicsDAE::Update	(	double	time,
		bool	update_assets = `true`
	)

overrideprotectedvirtual

Perform any updates necessary at the current phase during the solution process.

This function is called at least once per step to update auxiliary data, internal states, etc. The default implementation updates the item's time stamp and its visualization assets (if any are defined anf only if requested).

Reimplemented from chrono::ChPhysicsItem.

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

/builds/uwsbel/chrono/src/chrono/physics/ChExternalDynamicsDAE.h
/builds/uwsbel/chrono/src/chrono/physics/ChExternalDynamicsDAE.cpp

Description

Public Member Functions

Protected Member Functions

Additional Inherited Members

Member Function Documentation

◆ CalculateConstraintDerivative()

◆ CalculateConstraintJacobian()

◆ CalculateConstraintViolation()

◆ CalculateForce()

◆ CalculateForceJacobians()

◆ CalculateMassMatrix()

◆ CalculateMassTimesVector()

◆ CalculateStateIncrement()

◆ GetNumCoordsPosLevel()

◆ GetNumCoordsVelLevel()

◆ GetNumStateDerivatives()

◆ IncrementState()

◆ InExplicitForm()

◆ IntFromDescriptor()

◆ IntLoadConstraint_C()

◆ IntLoadConstraint_Ct()

◆ IntLoadLumpedMass_Md()

◆ IntLoadResidual_CqL()

◆ IntLoadResidual_F()

◆ IntLoadResidual_Mv()

◆ IntStateGather()

◆ IntStateGatherAcceleration()

◆ IntStateGatherReactions()

◆ IntStateGetIncrement()

◆ IntStateIncrement()

◆ IntStateScatter()

◆ IntStateScatterAcceleration()

◆ IntStateScatterReactions()

◆ IntToDescriptor()

◆ IsRheonomous()

◆ IsStiff()

◆ LoadKRMMatrices()

◆ OnUpdate()

◆ SetInitialConditions()

◆ Update()