SOFA API  83276a98
Open source framework for multi-physics simuation
sofa::component::constraint::lagrangian::solver::LCPConstraintSolver Class Reference

#include <LCPConstraintSolver.h>

Inheritance diagram for sofa::component::constraint::lagrangian::solver::LCPConstraintSolver:

Public Attributes

Data< boold_displayDebug
 Display debug information. More...
 
Data< boold_initial_guess
 activate LCP results history to improve its resolution performances. More...
 
Data< boold_build_lcp
 LCP is not fully built to increase performance in some case. More...
 
Data< SReald_tol
 residual error threshold for termination of the Gauss-Seidel algorithm More...
 
Data< intd_maxIt
 maximal number of iterations of the Gauss-Seidel algorithm More...
 
Data< SReald_regularizationTerm
 add regularization*Id to W when solving for constraints More...
 
Data< SReald_mu
 Friction coefficient. More...
 
Data< SReald_minW
 If not zero, constraints whose self-compliance (i.e. the corresponding value on the diagonal of W) is smaller than this threshold will be ignored. More...
 
Data< SReald_maxF
 If not zero, constraints whose response force becomes larger than this threshold will be ignored. More...
 
DeprecatedAndRemoved d_multi_grid
 activate multi_grid resolution (NOT STABLE YET) More...
 
DeprecatedAndRemoved d_multi_grid_levels
 if multi_grid is active: how many levels to create (>=2) More...
 
DeprecatedAndRemoved d_merge_method
 if multi_grid is active: which method to use to merge constraints (0 = compliance-based, 1 = spatial coordinates) More...
 
DeprecatedAndRemoved d_merge_spatial_step
 if merge_method is 1: grid size reduction between multigrid levels More...
 
DeprecatedAndRemoved d_merge_local_levels
 if merge_method is 1: up to the specified level of the multigrid, constraints are grouped locally, i.e. separately within each contact pairs, while on upper levels they are grouped globally independently of contact pairs. More...
 
Data< type::vector< SReal > > d_constraintForces
 OUTPUT: constraint forces (stored only if computeConstraintForces=True) More...
 
Data< boold_computeConstraintForces
 The indices of the constraintForces to store in the constraintForce data field. More...
 
Data< std::set< int > > d_constraintGroups
 list of ID of groups of constraints to be handled by this solver. More...
 
Data< std::map< std::string, sofa::type::vector< SReal > > > d_graph
 Graph of residuals at each iteration. More...
 
DeprecatedAndRemoved d_showLevels
 Number of constraint levels to display. More...
 
Data< SReald_showCellWidth
 Distance between each constraint cells. More...
 
Data< type::Vec3d_showTranslation
 Position of the first cell. More...
 
DeprecatedAndRemoved d_showLevelTranslation
 Translation between levels. More...
 
- Public Attributes inherited from sofa::core::behavior::ConstraintSolver
 SReal
 
- Public Attributes inherited from sofa::core::objectmodel::BaseObject
Data< boolf_listening
 if true, handle the events, otherwise ignore the events More...
 
- Public Attributes inherited from sofa::core::objectmodel::Base
std::vector< lifecycle::DeprecatedData * > m_oldAttributes
 
Data< intd_messageLogCount
 
Data< std::string > name
 Name of the object. More...
 
Data< boolf_printLog
 if true, emits extra messages at runtime. More...
 
Data< sofa::core::objectmodel::TagSetf_tags
 list of the subsets the object belongs to More...
 
Data< sofa::type::BoundingBoxf_bbox
 this object bounding box More...
 
Data< sofa::core::objectmodel::ComponentStated_componentState
 The state of the component among (Dirty, Valid, Undefined, Loading, Invalid). More...
 
std::string m_definitionSourceFileName {""}
 
int m_definitionSourceFilePos {-1}
 
std::string m_instanciationSourceFileName {""}
 
int m_instanciationSourceFilePos {-1}
 

Public Member Functions

 SOFA_CLASS (LCPConstraintSolver, ConstraintSolverImpl)
 
bool prepareStates (const core::ConstraintParams *, MultiVecId res1, MultiVecId res2=MultiVecId::null()) override
 
bool buildSystem (const core::ConstraintParams *, MultiVecId res1, MultiVecId res2=MultiVecId::null()) override
 
bool solveSystem (const core::ConstraintParams *, MultiVecId res1, MultiVecId res2=MultiVecId::null()) override
 
bool applyCorrection (const core::ConstraintParams *, MultiVecId res1, MultiVecId res2=MultiVecId::null()) override
 
ConstraintProblemgetConstraintProblem () override
 
void lockConstraintProblem (sofa::core::objectmodel::BaseObject *from, ConstraintProblem *p1, ConstraintProblem *p2=nullptr) override
 Do not use the following LCPs until the next call to this function. This is used to prevent concurrent access to the LCP when using a LCPForceFeedback through an haptic thread. More...
 
- Public Member Functions inherited from sofa::component::constraint::lagrangian::solver::ConstraintSolverImpl
 ConstraintSolverImpl ()
 
 ~ConstraintSolverImpl () override
 
void init () override
 Initialization method called at graph creation and modification, during top-down traversal. More...
 
void cleanup () override
 
void removeConstraintCorrection (core::behavior::BaseConstraintCorrection *s) override
 
- Public Member Functions inherited from sofa::core::behavior::ConstraintSolver
 SOFA_ABSTRACT_CLASS (ConstraintSolver, objectmodel::BaseObject)
 
virtual void solveConstraint (const ConstraintParams *, MultiVecId res1, MultiVecId res2=MultiVecId::null())
 
 SOFA_ATTRIBUTE_DEPRECATED__REBUILDSYSTEM () virtual void rebuildSystem(SReal
 
virtual void computeResidual (const core::ExecParams *)
 
bool insertInNode (objectmodel::BaseNode *node) override
 
bool removeInNode (objectmodel::BaseNode *node) override
 
virtual MultiVecDerivId getLambda () const
 
virtual MultiVecDerivId getDx () const
 
- Public Member Functions inherited from sofa::core::objectmodel::BaseObject
 SOFA_CLASS (BaseObject, Base)
 
virtual void draw (const core::visual::VisualParams *)
 Render internal data of this object, for debugging purposes. More...
 
virtual void computeBBox (const core::ExecParams *, bool=false)
 
void setSrc (const std::string &v, std::vector< std::string > *attributeList=nullptr)
 Sets a source Object and parses it to collect dependent Data. More...
 
void setSrc (const std::string &v, const BaseObject *loader, std::vector< std::string > *attributeList=nullptr)
 
BasefindLinkDestClass (const BaseClass *destType, const std::string &path, const BaseLink *link) override
 
virtual std::string getPathName () const override
 Return the full path name of this object. More...
 
SReal getTime () const
 Current time. More...
 
const BaseContextgetContext () const
 
BaseContextgetContext ()
 
const BaseObjectgetMaster () const
 
BaseObjectgetMaster ()
 
const VecSlavesgetSlaves () const
 
BaseObjectgetSlave (const std::string &name) const
 
virtual void addSlave (BaseObject::SPtr s)
 
virtual void removeSlave (BaseObject::SPtr s)
 
virtual void handleEvent (Event *)
 Handle an event. More...
 
virtual void handleTopologyChange ()
 
virtual void handleTopologyChange (core::topology::Topology *t)
 
void parse (BaseObjectDescription *arg) override
 Parse the given description to assign values to this object's fields and potentially other parameters. More...
 
virtual void bwdInit ()
 Initialization method called at graph creation and modification, during bottom-up traversal. More...
 
virtual void reinit ()
 Update method called when variables used in precomputation are modified. More...
 
void updateInternal ()
 Update method called when variables (used to compute other internal variables) are modified. More...
 
virtual void storeResetState ()
 Save the initial state for later uses in reset() More...
 
virtual void reset ()
 Reset to initial state. More...
 
- Public Member Functions inherited from sofa::core::objectmodel::Base
virtual const BaseClassgetClass () const
 
void addDeprecatedAttribute (lifecycle::DeprecatedData *attribute)
 
void addUpdateCallback (const std::string &name, std::initializer_list< BaseData * > inputs, std::function< sofa::core::objectmodel::ComponentState(const DataTracker &)> function, std::initializer_list< BaseData * > outputs)
 
void addOutputsToCallback (const std::string &name, std::initializer_list< BaseData * > outputs)
 
const std::string & getName () const
 Accessor to the object name. More...
 
void setName (const std::string &n)
 Set the name of this object. More...
 
void setName (const std::string &n, int counter)
 Set the name of this object, adding an integer counter. More...
 
std::string getTypeName () const
 Get the type name of this object (i.e. class and template types) More...
 
virtual std::string getClassName () const
 Get the class name of this object. More...
 
virtual std::string getTemplateName () const final
 Get the template type names (if any) used to instantiate this object. More...
 
std::string getNameSpaceName () const
 Get the template type names (if any) used to instantiate this object. More...
 
void setDefinitionSourceFileName (const std::string &sourceFileName)
 Set the source filename (where the component is implemented) More...
 
const std::string & getDefinitionSourceFileName () const
 Get the source filename (where the component is implemented) More...
 
void setDefinitionSourceFilePos (const int)
 Set the source location (where the component is implemented) More...
 
int getDefinitionSourceFilePos () const
 Get the source location (where the component is implemented) More...
 
void setInstanciationSourceFileName (const std::string &sourceFileName)
 
const std::string & getInstanciationSourceFileName () const
 
void setInstanciationSourceFilePos (const int)
 
int getInstanciationSourceFilePos () const
 
void addMessage (const sofa::helper::logging::Message &m) const
 
size_t countLoggedMessages (sofa::helper::logging::Message::TypeSet t=sofa::helper::logging::Message::AnyTypes) const
 
const std::deque< sofa::helper::logging::Message > & getLoggedMessages () const
 
const std::string getLoggedMessagesAsString (sofa::helper::logging::Message::TypeSet t=sofa::helper::logging::Message::AnyTypes) const
 
void clearLoggedMessages () const
 
bool notMuted () const
 
const sofa::core::objectmodel::TagSetgetTags () const
 Represents the subsets the object belongs to. More...
 
bool hasTag (Tag t) const
 Return true if the object belong to the given subset. More...
 
void addTag (Tag t)
 Add a subset qualification to the object. More...
 
void removeTag (Tag t)
 Remove a subset qualification to the object. More...
 
ComponentState getComponentState () const
 
bool isComponentStateValid () const
 
bool isComponentStateInvalid () const
 
 SOFA_ATTRIBUTE_DEPRECATED__TOBASECONSTRAINT () virtual const behavior
 
virtual bool parseField (const std::string &attribute, const std::string &value)
 Assign one field value (Data or Link) More...
 
virtual bool hasField (const std::string &attribute) const
 Check if a given Data field or Link exists. More...
 
void parseFields (const std::list< std::string > &str)
 Assign the field values stored in the given list of name + value pairs of strings. More...
 
virtual void parseFields (const std::map< std::string, std::string * > &str)
 Assign the field values stored in the given map of name -> value pairs. More...
 
void writeDatas (std::map< std::string, std::string * > &str)=delete
 Write the current field values to the given map of name -> value pairs. More...
 
void writeDatas (std::ostream &out, const std::string &separator=" ")
 
BaseDatafindData (const std::string &name) const
 
std::vector< BaseData * > findGlobalField (const std::string &name) const
 Find data fields given a name: several can be found as we look into the alias map. More...
 
BaseLinkfindLink (const std::string &name) const
 
std::vector< BaseLink * > findLinks (const std::string &name) const
 Find link fields given a name: several can be found as we look into the alias map. More...
 
virtual void updateLinks (bool logErrors=true)
 Update pointers in case the pointed-to objects have appeared. More...
 
template<class T >
BaseData::BaseInitData initData (::sofa::core::objectmodel::Data< T > *field, const char *name, const char *help, ::sofa::core::objectmodel::BaseData::DataFlags dataflags)
 Helper method used to initialize a data field containing a value of type T. More...
 
template<class T >
BaseData::BaseInitData initData (Data< T > *field, const char *name, const char *help, bool isDisplayed=true, bool isReadOnly=false)
 Helper method used to initialize a data field containing a value of type T. More...
 
template<class T >
Data< T >::InitData initData (Data< T > *field, const T &value, const char *name, const char *help, bool isDisplayed=true, bool isReadOnly=false)
 Helper method used to initialize a data field containing a value of type T. More...
 
void addData (BaseData *f, const std::string &name)
 
void addData (BaseData *f)
 
void removeData (BaseData *f)
 Remove a data field. More...
 
void addAlias (BaseData *field, const char *alias)
 Add an alias to a Data. More...
 
void addLink (BaseLink *l)
 Add a link. More...
 
void addAlias (BaseLink *link, const char *alias)
 Add an alias to a Link. More...
 
const VecDatagetDataFields () const
 Accessor to the vector containing all the fields of this object. More...
 
const MapDatagetDataAliases () const
 Accessor to the map containing all the aliases of this object. More...
 
const VecLinkgetLinks () const
 Accessor to the vector containing all the fields of this object. More...
 
const MapLinkgetLinkAliases () const
 Accessor to the map containing all the aliases of this object. More...
 
virtual bool findDataLinkDest (BaseData *&ptr, const std::string &path, const BaseLink *link)
 
template<class T >
bool findLinkDest (T *&ptr, const std::string &path, const BaseLink *link)
 

Protected Member Functions

 LCPConstraintSolver ()
 Default Constructor. More...
 
 ~LCPConstraintSolver () override
 Default Destructor. More...
 
- Protected Member Functions inherited from sofa::component::constraint::lagrangian::solver::ConstraintSolverImpl
void postBuildSystem (const core::ConstraintParams *cParams) override
 
void postSolveSystem (const core::ConstraintParams *cParams) override
 
void clearConstraintCorrections ()
 
void resetConstraints (const core::ConstraintParams *cParams)
 
void buildLocalConstraintMatrix (const core::ConstraintParams *cparams, unsigned int &constraintId)
 Call the method buildConstraintMatrix on all the BaseConstraintSet. More...
 
void accumulateMatrixDeriv (const core::ConstraintParams *cparams)
 
unsigned int buildConstraintMatrix (const core::ConstraintParams *cparams)
 
void applyProjectiveConstraintOnConstraintMatrix (const core::ConstraintParams *cparams)
 
void getConstraintViolation (const core::ConstraintParams *cparams, sofa::linearalgebra::BaseVector *v)
 
- Protected Member Functions inherited from sofa::core::behavior::ConstraintSolver
 ConstraintSolver ()
 
 ~ConstraintSolver () override
 
bool prepareStatesTask (const ConstraintParams *, MultiVecId res1, MultiVecId res2)
 
bool buildSystemTask (const ConstraintParams *, MultiVecId res1, MultiVecId res2)
 
bool solveSystemTask (const ConstraintParams *, MultiVecId res1, MultiVecId res2)
 
bool applyCorrectionTask (const ConstraintParams *, MultiVecId res1, MultiVecId res2)
 
- Protected Member Functions inherited from sofa::core::objectmodel::BaseObject
 BaseObject ()
 
 ~BaseObject () override
 
virtual void doUpdateInternal ()
 Implementation of the internal update. More...
 
void changeContextLink (BaseContext *before, BaseContext *&after)
 
void changeSlavesLink (BaseObject::SPtr ptr, std::size_t, bool add)
 This method insures that slaves objects have master and context links set correctly. More...
 
void trackInternalData (const BaseData &data)
 Method called to add the Data to the DataTracker (listing the Data to track) More...
 
void cleanTracker ()
 
bool hasDataChanged (const BaseData &data)
 Method called to know if a tracked Data has changed. More...
 
- Protected Member Functions inherited from sofa::core::objectmodel::Base
 Base ()
 
virtual ~Base ()
 
void initData0 (BaseData *field, BaseData::BaseInitData &res, const char *name, const char *help, bool isDisplayed=true, bool isReadOnly=false)
 Helper method used by initData() More...
 
void initData0 (BaseData *field, BaseData::BaseInitData &res, const char *name, const char *help, BaseData::DataFlags dataFlags)
 Helper method used by initData() More...
 
template<class T >
void initData0 (Data< T > *field, typename Data< T >::InitData &res, const T &value, const char *name, const char *help, bool isDisplayed=true, bool isReadOnly=false)
 Helper method used by initData() More...
 
- Protected Member Functions inherited from sofa::core::IntrusiveObject
virtual ~IntrusiveObject ()=default
 

Additional Inherited Members

- Protected Attributes inherited from sofa::component::constraint::lagrangian::solver::ConstraintSolverImpl
MultiLink< ConstraintSolverImpl, core::behavior::BaseConstraintCorrection, BaseLink::FLAG_STOREPATHl_constraintCorrections
 
- Protected Attributes inherited from sofa::core::objectmodel::BaseObject
SingleLink< BaseObject, BaseContext, BaseLink::FLAG_DOUBLELINKl_context
 
LinkSlaves l_slaves
 
SingleLink< BaseObject, BaseObject, BaseLink::FLAG_DOUBLELINKl_master
 
- Protected Attributes inherited from sofa::core::objectmodel::Base
std::map< std::string, sofa::core::DataTrackerCallbackm_internalEngine
 
VecData m_vecData
 List of fields (Data instances) More...
 
MapData m_aliasData
 name -> Data multi-map (includes names and aliases) More...
 
VecLink m_vecLink
 List of links. More...
 
MapLink m_aliasLink
 name -> Link multi-map (includes names and aliases) More...
 
- Static Public Member Functions inherited from sofa::core::objectmodel::BaseObject
template<class T >
static bool canCreate (T *, BaseContext *, BaseObjectDescription *)
 Pre-construction check method called by ObjectFactory. More...
 
template<class T >
static T::SPtr create (T *, BaseContext *context, BaseObjectDescription *arg)
 Construction method called by ObjectFactory. More...
 
- Static Public Member Functions inherited from sofa::core::objectmodel::Base
static const BaseClassGetClass ()
 
template<class T >
static std::string shortName (const T *ptr=nullptr, BaseObjectDescription *=nullptr)
 

Attribute details

◆ d_build_lcp

Data<bool> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_build_lcp

LCP is not fully built to increase performance in some case.

◆ d_computeConstraintForces

Data<bool> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_computeConstraintForces

The indices of the constraintForces to store in the constraintForce data field.

◆ d_constraintForces

Data<type::vector< SReal > > sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_constraintForces

OUTPUT: constraint forces (stored only if computeConstraintForces=True)

◆ d_constraintGroups

Data< std::set<int> > sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_constraintGroups

list of ID of groups of constraints to be handled by this solver.

◆ d_displayDebug

Data<bool> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_displayDebug

Display debug information.

◆ d_graph

Data<std::map < std::string, sofa::type::vector<SReal> > > sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_graph

Graph of residuals at each iteration.

◆ d_initial_guess

Data<bool> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_initial_guess

activate LCP results history to improve its resolution performances.

◆ d_maxF

Data<SReal> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_maxF

If not zero, constraints whose response force becomes larger than this threshold will be ignored.

◆ d_maxIt

Data<int> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_maxIt

maximal number of iterations of the Gauss-Seidel algorithm

◆ d_merge_local_levels

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_merge_local_levels

if merge_method is 1: up to the specified level of the multigrid, constraints are grouped locally, i.e. separately within each contact pairs, while on upper levels they are grouped globally independently of contact pairs.

◆ d_merge_method

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_merge_method

if multi_grid is active: which method to use to merge constraints (0 = compliance-based, 1 = spatial coordinates)

◆ d_merge_spatial_step

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_merge_spatial_step

if merge_method is 1: grid size reduction between multigrid levels

◆ d_minW

Data<SReal> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_minW

If not zero, constraints whose self-compliance (i.e. the corresponding value on the diagonal of W) is smaller than this threshold will be ignored.

◆ d_mu

Data<SReal> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_mu

Friction coefficient.

◆ d_multi_grid

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_multi_grid

activate multi_grid resolution (NOT STABLE YET)

◆ d_multi_grid_levels

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_multi_grid_levels

if multi_grid is active: how many levels to create (>=2)

◆ d_regularizationTerm

Data<SReal> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_regularizationTerm

add regularization*Id to W when solving for constraints

◆ d_showCellWidth

Data<SReal> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_showCellWidth

Distance between each constraint cells.

◆ d_showLevels

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_showLevels

Number of constraint levels to display.

◆ d_showLevelTranslation

DeprecatedAndRemoved sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_showLevelTranslation

Translation between levels.

◆ d_showTranslation

Data<type::Vec3> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_showTranslation

Position of the first cell.

◆ d_tol

Data<SReal> sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::d_tol

residual error threshold for termination of the Gauss-Seidel algorithm

Constructor details

◆ LCPConstraintSolver()

sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::LCPConstraintSolver ( )
protected

Default Constructor.

◆ ~LCPConstraintSolver()

sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::~LCPConstraintSolver ( )
overrideprotected

Default Destructor.

Function details

◆ applyCorrection()

bool sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::applyCorrection ( const core::ConstraintParams ,
MultiVecId  res1,
MultiVecId  res2 = MultiVecId::null() 
)
overridevirtual

Correct the Mechanical State with the solution found

Implements sofa::core::behavior::ConstraintSolver.

◆ buildSystem()

bool sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::buildSystem ( const core::ConstraintParams ,
MultiVecId  res1,
MultiVecId  res2 = MultiVecId::null() 
)
overridevirtual

Create the system corresponding to the constraints

Implements sofa::core::behavior::ConstraintSolver.

◆ getConstraintProblem()

ConstraintProblem * sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::getConstraintProblem ( )
overridevirtual

◆ lockConstraintProblem()

void sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::lockConstraintProblem ( sofa::core::objectmodel::BaseObject from,
ConstraintProblem p1,
ConstraintProblem p2 = nullptr 
)
overridevirtual

Do not use the following LCPs until the next call to this function. This is used to prevent concurrent access to the LCP when using a LCPForceFeedback through an haptic thread.

Implements sofa::component::constraint::lagrangian::solver::ConstraintSolverImpl.

◆ prepareStates()

bool sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::prepareStates ( const core::ConstraintParams ,
MultiVecId  res1,
MultiVecId  res2 = MultiVecId::null() 
)
overridevirtual

Do the precomputation: compute free state, or propagate the states to the mapped mechanical states, where the constraint can be expressed

Implements sofa::core::behavior::ConstraintSolver.

◆ SOFA_CLASS()

sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::SOFA_CLASS ( LCPConstraintSolver  ,
ConstraintSolverImpl   
)

◆ solveSystem()

bool sofa::component::constraint::lagrangian::solver::LCPConstraintSolver::solveSystem ( const core::ConstraintParams ,
MultiVecId  res1,
MultiVecId  res2 = MultiVecId::null() 
)
override