Description

Constraint combining two tuples, each referencing 1, 2, or 3 variable objects.

This allows representing a constraint between two objects with different number of variable sets. Typically used for implementing unilateral contact constraints, this could represent for example a contact between an edge with 2 "xyz" variables and a triangle with 3 "xyz" variables; in this case, the contact constraint Jacobian is split in 2 + 3 chunks.

#include <ChConstraintTwoTuples.h>

Inheritance diagram for chrono::ChConstraintTwoTuples:

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Collaboration diagram for chrono::ChConstraintTwoTuples:

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Public Member Functions
	ChConstraintTwoTuples (const ChConstraintTwoTuples &other)

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

ChConstraintTwoTuples &	operator= (const ChConstraintTwoTuples &other)
	Assignment operator: copy from other object.

ChConstraintTuple *	TupleA ()
	Access tuple a.

ChConstraintTuple *	TupleB ()
	Access tuple b.

void	SetTuples (ChConstraintTuple tupleA, ChConstraintTuple tupleB)
	Set the two tuples.

void	SetTuplesFromContactables (ChContactable objA, ChContactable objB)
	Set the two tuples from two contactable objects.

virtual void	UpdateAuxiliary () override
	This function updates the following auxiliary data: More...

virtual double	ComputeJacobianTimesState () override
	Compute the product between the Jacobian of this constraint, [Cq_i], and the vector of variables. More...

virtual void	IncrementState (double deltal) override
	Increment the vector of variables with the quantity [invM][Cq_i]'deltal. More...

virtual void	AddJacobianTimesVectorInto (double &result, ChVectorConstRef vect) const override
	Add the product of the corresponding block in the system matrix by 'vect' and add to result. More...

virtual void	AddJacobianTransposedTimesScalarInto (ChVectorRef result, double l) const override
	Add the product of the corresponding transposed block in the system matrix by 'l' and add to result. More...

virtual void	PasteJacobianInto (ChSparseMatrix &mat, unsigned int start_row, unsigned int start_col) const override
	Write the constraint Jacobian into the specified global matrix at the offsets of the associated variables. More...

virtual void	PasteJacobianTransposedInto (ChSparseMatrix &mat, unsigned int start_row, unsigned int start_col) const override
	Write the transposed constraint Jacobian into the specified global matrix at the offsets of the associated variables. More...

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

ChConstraint &	operator= (const ChConstraint &other)
	Assignment operator: copy from other object.

bool	operator== (const ChConstraint &other) const
	Comparison (compares only flags, not the Jacobians).

bool	IsValid () const
	Indicate if the constraint data is currently valid.

void	SetValid (bool mon)
	Set the "valid" state of this constraint.

bool	IsDisabled () const
	Indicate if the constraint is currently turned on or off.

void	SetDisabled (bool mon)

bool	IsRedundant () const
	Indicate if the constraint is redundant or singular.

void	SetRedundant (bool mon)
	Mark the constraint as redundant.

bool	IsBroken () const
	Indicate if the constraint is broken, due to excess pulling/pushing.

void	SetBroken (bool mon)
	Set the constraint as broken. More...

virtual bool	IsUnilateral () const
	Indicate if the constraint is unilateral (typical complementarity constraint).

virtual bool	IsLinear () const
	Indicate if the constraint is linear.

Mode	GetMode () const
	Get the mode of the constraint. More...

void	SetMode (Mode mmode)
	Set the mode of the constraint.

bool	IsActive () const
	Indicate whether the constraint is currently active. More...

void	SetActive (bool isactive)
	Set the status of the constraint to active.

virtual double	ComputeResidual ()
	Compute the residual of the constraint using the linear expression. More...

double	GetResidual () const
	Return the residual of this constraint.

void	SetRightHandSide (const double mb)
	Sets the known term b_i in [Cq_i]q + b_i = 0, where: c_i = [Cq_i]q + b_i = 0.

double	GetRightHandSide () const
	Return the known term b_i in [Cq_i]q + b_i = 0, where: c_i= [Cq_i]q + b_i = 0.

void	SetComplianceTerm (const double mcfm)
	Set the constraint force mixing term (default=0). More...

double	GetComplianceTerm () const
	Return the constraint force mixing term.

void	SetLagrangeMultiplier (double ml_i)
	Set the value of the corresponding Lagrange multiplier (constraint reaction).

double	GetLagrangeMultiplier () const
	Return the corresponding Lagrange multiplier (constraint reaction).

double	GetSchurComplement () const
	Return the 'g_i' product, that is [Cq_i][invM_i][Cq_i]' (+cfm)

void	SetSchurComplement (double m_g_i)
	Usually you should not use the SetSchurComplement function, because g_i should be automatically computed during the UpdateAuxiliary() .

virtual void	Project ()
	Project the value of a possible 'l_i' value of constraint reaction onto admissible orthant/set. More...

virtual double	Violation (double mc_i)
	Return the constraint violation. More...

void	SetOffset (unsigned int off)
	Set offset in global q vector (set automatically by ChSystemDescriptor)

unsigned int	GetOffset () const
	Get offset in global q vector.

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

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

Protected Attributes
ChConstraintTuple *	tuple_a

ChConstraintTuple *	tuple_b

Protected Attributes inherited from chrono::ChConstraint
double	c_i
	constraint residual (if satisfied, c must be 0)

double	l_i
	Lagrange multiplier (reaction)

double	b_i
	right-hand side term in [Cq_i]q+b_i=0 , note: c_i= [Cq_i]q + b_i

double	cfm_i
	Constraint force mixing if needed to add some numerical 'compliance' in the constraint. More...

Mode	mode
	mode of the constraint

double	g_i
	product [Cq_i][invM_i][Cq_i]' (+cfm)

unsigned int	offset
	offset in global "l" state vector (needed by some solvers)

Additional Inherited Members
Public Types inherited from chrono::ChConstraint
enum	Mode { Mode::FREE, Mode::LOCK, Mode::UNILATERAL, Mode::FRICTION }
	Constraint mode. More...

Member Function Documentation

◆ AddJacobianTimesVectorInto()

void chrono::ChConstraintTwoTuples::AddJacobianTimesVectorInto	(	double &	result,
		ChVectorConstRef	vect
	)		const

overridevirtual

Add the product of the corresponding block in the system matrix by 'vect' and add to result.

Note: 'vect' is assumed to be of proper size; the procedure uses the ChVariable offsets to index in 'vect'.

Implements chrono::ChConstraint.

◆ AddJacobianTransposedTimesScalarInto()

void chrono::ChConstraintTwoTuples::AddJacobianTransposedTimesScalarInto	(	ChVectorRef	result,
		double	l
	)		const

overridevirtual

Add the product of the corresponding transposed block in the system matrix by 'l' and add to result.

Note: 'result' is assumed to be of proper size; the procedure uses the ChVariable offsets to index in 'result'.

Implements chrono::ChConstraint.

◆ ComputeJacobianTimesState()

double chrono::ChConstraintTwoTuples::ComputeJacobianTimesState ( )

overridevirtual

Compute the product between the Jacobian of this constraint, [Cq_i], and the vector of variables.

In other words, perform the operation:

  CV = [Cq_i] * v

Implements chrono::ChConstraint.

◆ IncrementState()

void chrono::ChConstraintTwoTuples::IncrementState ( double deltal )

overridevirtual

Increment the vector of variables with the quantity [invM]*[Cq_i]'*deltal.

In other words, perform the operation:

   v += [invM] * [Cq_i]' * deltal
or else
   v+=[Eq_i] * deltal

Implements chrono::ChConstraint.

◆ PasteJacobianInto()

void chrono::ChConstraintTwoTuples::PasteJacobianInto	(	ChSparseMatrix &	mat,
		unsigned int	start_row,
		unsigned int	start_col
	)		const

overridevirtual

Write the constraint Jacobian into the specified global matrix at the offsets of the associated variables.

The (start_row, start_col) pair specifies the top-left corner of the system-level constraint Jacobian in the provided matrix.

Implements chrono::ChConstraint.

◆ PasteJacobianTransposedInto()

void chrono::ChConstraintTwoTuples::PasteJacobianTransposedInto	(	ChSparseMatrix &	mat,
		unsigned int	start_row,
		unsigned int	start_col
	)		const

overridevirtual

Write the transposed constraint Jacobian into the specified global matrix at the offsets of the associated variables.

The (start_row, start_col) pair specifies the top-left corner of the system-level constraint Jacobian in the provided matrix.

Implements chrono::ChConstraint.

◆ UpdateAuxiliary()

void chrono::ChConstraintTwoTuples::UpdateAuxiliary ( )

overridevirtual

This function updates the following auxiliary data:

the Eq_a and Eq_b matrices
the g_i product This function is often called by solvers at the beginning of the solution process. Note: This function must be overridden by specialized derived classes, which have some Jacobians.

Reimplemented from chrono::ChConstraint.

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

/builds/uwsbel/chrono/src/chrono/solver/ChConstraintTwoTuples.h
/builds/uwsbel/chrono/src/chrono/solver/ChConstraintTwoTuples.cpp

Description

Public Member Functions

Protected Attributes

Additional Inherited Members

Member Function Documentation

◆ AddJacobianTimesVectorInto()

◆ AddJacobianTransposedTimesScalarInto()

◆ ComputeJacobianTimesState()

◆ IncrementState()

◆ PasteJacobianInto()

◆ PasteJacobianTransposedInto()

◆ UpdateAuxiliary()