Description

This class implements the functionality for a constraint between a COUPLE of TWO objects of type ChVariables(), with generic number of scalar variables each (ex.ChVariablesGeneric() or ChVariablesBody() ) and defines two constraint matrices, whose column number automatically matches the number of elements in variables vectors.

Before starting the solver one must provide the proper values in constraints (and update them if necessary), i.e. must set at least the c_i and b_i values, and jacobians.

#include <ChConstraintTwoGeneric.h>

Inheritance diagram for chrono::ChConstraintTwoGeneric:

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Collaboration diagram for chrono::ChConstraintTwoGeneric:

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Public Member Functions
	ChConstraintTwoGeneric ()
	Default constructor.

	ChConstraintTwoGeneric (ChVariables mvariables_a, ChVariables mvariables_b)
	Construct and immediately set references to variables.

	ChConstraintTwoGeneric (const ChConstraintTwoGeneric &other)
	Copy constructor.

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

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

virtual ChRowVectorRef	Get_Cq_a () override
	Access Jacobian vector.

virtual ChRowVectorRef	Get_Cq_b () override
	Access Jacobian vector.

virtual ChVectorRef	Get_Eq_a () override
	Access auxiliary vector (ex: used by iterative solvers).

virtual ChVectorRef	Get_Eq_b () override
	Access auxiliary vector (ex: used by iterative solvers).

virtual void	SetVariables (ChVariables mvariables_a, ChVariables mvariables_b) override
	Set references to the constrained ChVariables objects, automatically creating/resizing Jacobians as needed.

virtual void	Update_auxiliary () 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...

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 de-serialization of transient data from archives.

Public Member Functions inherited from chrono::ChConstraintTwo
	ChConstraintTwo ()
	Default constructor.

	ChConstraintTwo (const ChConstraintTwo &other)
	Copy constructor.

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

ChVariables *	GetVariables_a ()
	Access the first variable object.

ChVariables *	GetVariables_b ()
	Access the second variable object.

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 Update_auxiliary() .

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.

Protected Attributes
ChRowVectorDynamic< double >	Cq_a
	The [Cq_a] jacobian of the constraint.

ChRowVectorDynamic< double >	Cq_b
	The [Cq_b] jacobian of the constraint.

ChVectorDynamic< double >	Eq_a
	The [Eq_a] product [Eq_a]=[invM_a]*[Cq_a]'.

ChVectorDynamic< double >	Eq_b
	The [Eq_a] product [Eq_b]=[invM_b]*[Cq_b]'.

Protected Attributes inherited from chrono::ChConstraintTwo
ChVariables *	variables_a
	The first constrained object.

ChVariables *	variables_b
	The second constrained object.

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::ChConstraintTwoGeneric::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::ChConstraintTwoGeneric::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::ChConstraintTwoGeneric::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::ChConstraintTwoGeneric::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::ChConstraintTwoGeneric::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::ChConstraintTwoGeneric::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 transposed constraint Jacobian in the provided matrix.

Implements chrono::ChConstraint.

◆ Update_auxiliary()

void chrono::ChConstraintTwoGeneric::Update_auxiliary ( )

overridevirtual

This function updates the following auxiliary data:

the Eq_a and Eq_b matrices
the g_i product This is often called by solvers at the beginning of the solution process.

Reimplemented from chrono::ChConstraint.

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

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

Description

Public Member Functions

Protected Attributes

Additional Inherited Members

Member Function Documentation

◆ AddJacobianTimesVectorInto()

◆ AddJacobianTransposedTimesScalarInto()

◆ ComputeJacobianTimesState()

◆ IncrementState()

◆ PasteJacobianInto()

◆ PasteJacobianTransposedInto()

◆ Update_auxiliary()