chrono::ChConstraintTwo Class Referenceabstract

Description

This class implements the functionality for a constraint between a COUPLE of TWO objects of type ChVariables(), 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 <ChConstraintTwo.h>

Inheritance diagram for chrono::ChConstraintTwo:
Collaboration diagram for chrono::ChConstraintTwo:

Public Member Functions

 ChConstraintTwo ()
 Default constructor.
 
 ChConstraintTwo (const ChConstraintTwo &other)
 Copy constructor.
 
ChConstraintTwooperator= (const ChConstraintTwo &other)
 Assignment operator: copy from other object.
 
virtual ChRowVectorRef Get_Cq_a ()=0
 Access jacobian vector.
 
virtual ChRowVectorRef Get_Cq_b ()=0
 Access jacobian vector.
 
virtual ChVectorRef Get_Eq_a ()=0
 Access auxiliary vector (ex: used by iterative solvers).
 
virtual ChVectorRef Get_Eq_b ()=0
 Access auxiliary vector (ex: used by iterative solvers).
 
ChVariablesGetVariables_a ()
 Access the first variable object.
 
ChVariablesGetVariables_b ()
 Access the second variable object.
 
virtual void SetVariables (ChVariables *mvariables_a, ChVariables *mvariables_b)=0
 Set references to the constrained objects, each of ChVariables type, automatically creating/resizing jacobians if needed.
 
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::ChConstraint
 ChConstraint (const ChConstraint &other)
 
virtual ChConstraintClone () const =0
 "Virtual" copy constructor.
 
ChConstraintoperator= (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).
 
virtual void Update_auxiliary ()
 This function updates the following auxiliary data: More...
 
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 double ComputeJacobianTimesState ()=0
 Compute the product between the Jacobian of this constraint, [Cq_i], and the vector of variables. More...
 
virtual void IncrementState (double deltal)=0
 Increment the vector of variables with the quantity [invM]*[Cq_i]'*deltal. More...
 
virtual void AddJacobianTimesVectorInto (double &result, ChVectorConstRef vect) const =0
 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 =0
 Add the product of the corresponding transposed block in the system matrix by 'l' and add to result. More...
 
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...
 
virtual void PasteJacobianInto (ChSparseMatrix &mat, unsigned int start_row, unsigned int start_col) const =0
 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 =0
 Write the transposed constraint Jacobian into the specified global matrix at the offsets of the associated variables. 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

ChVariablesvariables_a
 The first constrained object.
 
ChVariablesvariables_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...
 

The documentation for this class was generated from the following files:
  • /builds/uwsbel/chrono/src/chrono/solver/ChConstraintTwo.h
  • /builds/uwsbel/chrono/src/chrono/solver/ChConstraintTwo.cpp