Description

Physical system.

This class is used to represent a multibody physical system, so it acts also as a database for most items involved in simulations, most noticeably objects of ChBody and ChLink classes, which are used to represent mechanisms.

Moreover, it also owns some global settings and features, like the gravity acceleration, the global time and so on.

This object will be responsible of performing the entire physical simulation (dynamics, kinematics, statics, etc.), so you need at least one ChSystem object in your program, in order to perform simulations (you'll insert rigid bodies and links into it..)

Note that this is an abstract class, in your code you must create a system from one of the concrete classes: chrono::ChSystemNSC (for non-smooth contacts) or chrono::ChSystemSMC (for smooth 'penalty' contacts).

Further info at the Simulation system manual page.

#include <ChSystem.h>

Inheritance diagram for chrono::ChSystem:

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Collaboration diagram for chrono::ChSystem:

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Classes
class	CustomCollisionCallback
	Class to be used as a callback interface for user defined actions performed at each collision detection step. More...

Public Member Functions
	ChSystem ()
	Create a physical system.

	ChSystem (const ChSystem &other)
	Copy constructor.

virtual	~ChSystem ()
	Destructor.

virtual ChSystem *	Clone () const =0
	"Virtual" copy constructor. More...

void	SetStep (double m_step)
	Sets the time step used for integration (dynamical simulation). More...

double	GetStep () const
	Gets the current time step used for the integration (dynamical simulation).

void	SetTimestepperType (ChTimestepper::Type type)
	Set the method for time integration (time stepper type). More...

ChTimestepper::Type	GetTimestepperType () const
	Get the current method for time integration (time stepper type).

void	SetTimestepper (std::shared_ptr< ChTimestepper > mstepper)
	Set the timestepper object to be used for time integration.

std::shared_ptr< ChTimestepper >	GetTimestepper () const
	Get the timestepper currently used for time integration.

void	SetMaxiter (int m_maxiter)
	Sets outer iteration limit for assembly constraints. More...

int	GetMaxiter () const
	Gets iteration limit for assembly constraints.

virtual void	SetMaterialCompositionStrategy (std::unique_ptr< ChMaterialCompositionStrategy > &&strategy)
	Change the default composition laws for contact surface materials (coefficient of friction, cohesion, compliance, etc.)

const ChMaterialCompositionStrategy &	GetMaterialCompositionStrategy () const
	Accessor for the current composition laws for contact surface material.

void	SetMinBounceSpeed (double mval)
	For elastic collisions, with objects that have nonzero restitution coefficient: objects will rebounce only if their relative colliding speed is above this threshold. More...

double	GetMinBounceSpeed () const
	Objects will rebounce only if their relative colliding speed is above this threshold.

void	SetMaxPenetrationRecoverySpeed (double mval)
	For the default stepper, you can limit the speed of exiting from penetration situations. More...

double	GetMaxPenetrationRecoverySpeed () const
	Get the limit on the speed for exiting from penetration situations (for Anitescu stepper)

virtual void	SetSolver (std::shared_ptr< ChSolver > newsolver)
	Attach a solver (derived from ChSolver) for use by this system.

virtual std::shared_ptr< ChSolver >	GetSolver ()
	Access the solver currently associated with this system.

void	SetSolverType (ChSolver::Type type)
	Choose the solver type, to be used for the simultaneous solution of the constraints in dynamical simulations (as well as in kinematics, statics, etc.) More...

ChSolver::Type	GetSolverType () const
	Gets the current solver type.

void	SetSolverMaxIterations (int max_iters)
	Set the maximum number of iterations, if using an iterative solver. More...

int	GetSolverMaxIterations () const
	Get the current maximum number of iterations, if using an iterative solver. More...

void	SetSolverTolerance (double tolerance)
	Set the solver tolerance threshold (used with iterative solvers only). More...

double	GetSolverTolerance () const
	Get the current tolerance value (used with iterative solvers only).

void	SetSolverForceTolerance (double tolerance)
	Set a solver tolerance threshold at force level (default: not specified). More...

double	GetSolverForceTolerance () const
	Get the current value of the force-level tolerance (used with iterative solvers only).

void	SetSystemDescriptor (std::shared_ptr< ChSystemDescriptor > newdescriptor)
	Instead of using the default 'system descriptor', you can create your own custom descriptor (inherited from ChSystemDescriptor) and plug it into the system using this function.

std::shared_ptr< ChSystemDescriptor >	GetSystemDescriptor ()
	Access directly the 'system descriptor'.

void	Set_G_acc (const ChVector<> &m_acc)
	Set the G (gravity) acceleration vector, affecting all the bodies in the system.

const ChVector &	Get_G_acc () const
	Get the G (gravity) acceleration vector affecting all the bodies in the system.

double	GetChTime () const
	Get the simulation time of this system.

void	SetChTime (double time)
	Set (overwrite) the simulation time of this system.

virtual void	SetNumThreads (int num_threads_chrono, int num_threads_collision=0, int num_threads_eigen=0)
	Set the number of OpenMP threads used by Chrono itself, Eigen, and the collision detection system. More...

int	GetNumThreadsChrono () const

int	GetNumthreadsCollision () const

int	GetNumthreadsEigen () const

const ChAssembly &	GetAssembly () const
	Get the underlying assembly containing all physics items.

virtual void	AddBody (std::shared_ptr< ChBody > body)
	Attach a body to the underlying assembly.

virtual void	AddShaft (std::shared_ptr< ChShaft > shaft)
	Attach a shaft to the underlying assembly.

virtual void	AddLink (std::shared_ptr< ChLinkBase > link)
	Attach a link to the underlying assembly.

virtual void	AddMesh (std::shared_ptr< fea::ChMesh > mesh)
	Attach a mesh to the underlying assembly.

virtual void	AddOtherPhysicsItem (std::shared_ptr< ChPhysicsItem > item)
	Attach a ChPhysicsItem object that is not a body, link, or mesh.

void	Add (std::shared_ptr< ChPhysicsItem > item)
	Attach an arbitrary ChPhysicsItem (e.g. More...

void	AddBatch (std::shared_ptr< ChPhysicsItem > item)
	Items added in this way are added like in the Add() method, but not instantly, they are simply queued in a batch of 'to add' items, that are added automatically at the first Setup() call. More...

void	FlushBatch ()
	If some items are queued for addition in the assembly, using AddBatch(), this will effectively add them and clean the batch. More...

virtual void	RemoveBody (std::shared_ptr< ChBody > body)
	Remove a body from this assembly.

virtual void	RemoveShaft (std::shared_ptr< ChShaft > shaft)
	Remove a shaft from this assembly.

virtual void	RemoveLink (std::shared_ptr< ChLinkBase > link)
	Remove a link from this assembly.

virtual void	RemoveMesh (std::shared_ptr< fea::ChMesh > mesh)
	Remove a mesh from the assembly.

virtual void	RemoveOtherPhysicsItem (std::shared_ptr< ChPhysicsItem > item)
	Remove a ChPhysicsItem object that is not a body or a link.

void	Remove (std::shared_ptr< ChPhysicsItem > item)
	Remove arbitrary ChPhysicsItem that was added to the underlying assembly.

void	RemoveAllBodies ()
	Remove all bodies from the underlying assembly.

void	RemoveAllShafts ()
	Remove all shafts from the underlying assembly.

void	RemoveAllLinks ()
	Remove all links from the underlying assembly.

void	RemoveAllMeshes ()
	Remove all meshes from the underlying assembly.

void	RemoveAllOtherPhysicsItems ()
	Remove all physics items not in the body, link, or mesh lists.

const std::vector< std::shared_ptr< ChBody > > &	Get_bodylist () const
	Get the list of bodies.

const std::vector< std::shared_ptr< ChShaft > > &	Get_shaftlist () const
	Get the list of shafts.

const std::vector< std::shared_ptr< ChLinkBase > > &	Get_linklist () const
	Get the list of links.

const std::vector< std::shared_ptr< fea::ChMesh > > &	Get_meshlist () const
	Get the list of meshes.

const std::vector< std::shared_ptr< ChPhysicsItem > > &	Get_otherphysicslist () const
	Get the list of physics items that are not in the body or link lists.

std::shared_ptr< ChBody >	SearchBody (const char *name)
	Search a body by its name.

std::shared_ptr< ChBody >	SearchBodyID (int bodyID)
	Search a body by its ID.

std::shared_ptr< ChShaft >	SearchShaft (const char *name)
	Search a shaft by its name.

std::shared_ptr< ChLinkBase >	SearchLink (const char *name)
	Search a link by its name.

std::shared_ptr< fea::ChMesh >	SearchMesh (const char *name)
	Search a mesh by its name.

std::shared_ptr< ChPhysicsItem >	SearchOtherPhysicsItem (const char *name)
	Search from other ChPhysics items (not bodies, links, or meshes) by name.

std::shared_ptr< ChMarker >	SearchMarker (const char *name)
	Search a marker by its name.

std::shared_ptr< ChMarker >	SearchMarker (int markID)
	Search a marker by its unique ID.

std::shared_ptr< ChPhysicsItem >	Search (const char *name)
	Search an item (body, link or other ChPhysics items) by name.

int	GetNbodies () const
	Get the number of active bodies (excluding those that are sleeping or are fixed to ground).

int	GetNbodiesSleeping () const
	Get the number of bodies that are in sleeping mode (excluding fixed bodies).

int	GetNbodiesFixed () const
	Get the number of bodies that are fixed to ground.

int	GetNbodiesTotal () const
	Get the total number of bodies in the assembly, including the grounded and sleeping bodies.

int	GetNshafts () const
	Get the number of shafts.

int	GetNshaftsSleeping () const
	Get the number of shafts that are in sleeping mode (excluding fixed shafts).

int	GetNshaftsFixed () const
	Get the number of shafts that are fixed to ground.

int	GetNshaftsTotal () const
	Get the total number of shafts added to the assembly, including the grounded and sleeping shafts.

int	GetNlinks () const
	Get the number of links.

int	GetNmeshes () const
	Get the number of meshes.

int	GetNphysicsItems () const
	Get the number of other physics items (other than bodies, links, or meshes).

int	GetNcoords () const
	Get the number of coordinates (considering 7 coords for rigid bodies because of the 4 dof of quaternions).

int	GetNdof () const
	Get the number of degrees of freedom of the assembly.

int	GetNdoc () const
	Get the number of scalar constraints added to the assembly, including constraints on quaternion norms.

int	GetNsysvars () const
	Get the number of system variables (coordinates plus the constraint multipliers, in case of quaternions).

int	GetNcoords_w () const
	Get the number of coordinates (considering 6 coords for rigid bodies, 3 transl.+3rot.)

int	GetNdoc_w () const
	Get the number of scalar constraints added to the assembly.

int	GetNdoc_w_C () const
	Get the number of scalar constraints added to the assembly (only bilaterals).

int	GetNdoc_w_D () const
	Get the number of scalar constraints added to the assembly (only unilaterals).

int	GetNsysvars_w () const
	Get the number of system variables (coordinates plus the constraint multipliers).

int	GetDOF () const
	Get the number of scalar coordinates (ex. dim of position vector)

int	GetDOF_w () const
	Get the number of scalar coordinates of variables derivatives (ex. dim of speed vector)

int	GetDOC () const
	Get the number of scalar constraints, if any, in this item.

int	GetDOC_c () const
	Get the number of scalar constraints, if any, in this item (only bilateral constr.)

int	GetDOC_d () const
	Get the number of scalar constraints, if any, in this item (only unilateral constr.)

void	ShowHierarchy (ChStreamOutAscii &m_file, int level=0) const
	Write the hierarchy of contained bodies, markers, etc. More...

void	Clear ()
	Removes all bodies/marker/forces/links/contacts, also resets timers and events.

virtual ChContactMethod	GetContactMethod () const =0
	Return the contact method supported by this system. More...

virtual ChBody *	NewBody ()
	Create and return the pointer to a new body. More...

virtual ChBodyAuxRef *	NewBodyAuxRef ()
	Create and return the pointer to a new body with auxiliary reference frame. More...

void	Reference_LM_byID ()
	Given inserted markers and links, restores the pointers of links to markers given the information about the marker IDs. More...

int	GetNcontacts ()
	Gets the number of contacts.

virtual double	GetTimerStep () const
	Return the time (in seconds) spent for computing the time step.

virtual double	GetTimerAdvance () const
	Return the time (in seconds) for time integration, within the time step.

virtual double	GetTimerLSsolve () const
	Return the time (in seconds) for the solver, within the time step. More...

virtual double	GetTimerLSsetup () const
	Return the time (in seconds) for the solver Setup phase, within the time step.

virtual double	GetTimerJacobian () const
	Return the time (in seconds) for calculating/loading Jacobian information, within the time step.

virtual double	GetTimerCollision () const
	Return the time (in seconds) for runnning the collision detection step, within the time step.

virtual double	GetTimerSetup () const
	Return the time (in seconds) for system setup, within the time step.

virtual double	GetTimerUpdate () const
	Return the time (in seconds) for updating auxiliary data, within the time step.

double	GetTimerCollisionBroad () const
	Return the time (in seconds) for broadphase collision detection, within the time step.

double	GetTimerCollisionNarrow () const
	Return the time (in seconds) for narrowphase collision detection, within the time step.

void	ResetTimers ()
	Resets the timers.

virtual void	Setup ()
	Counts the number of bodies and links. More...

void	Update (double mytime, bool update_assets=true)
	Updates all the auxiliary data and children of bodies, forces, links, given their current state.

void	Update (bool update_assets=true)
	Updates all the auxiliary data and children of bodies, forces, links, given their current state.

void	ForceUpdate ()
	In normal usage, no system update is necessary at the beginning of a new dynamics step (since an update is performed at the end of a step). More...

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

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

void	InjectVariables (ChSystemDescriptor &mdescriptor)

void	InjectConstraints (ChSystemDescriptor &mdescriptor)

void	ConstraintsLoadJacobians ()

void	InjectKRMmatrices (ChSystemDescriptor &mdescriptor)

void	KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor)

void	VariablesFbReset ()

void	VariablesFbLoadForces (double factor=1)

void	VariablesQbLoadSpeed ()

void	VariablesFbIncrementMq ()

void	VariablesQbSetSpeed (double step=0)

void	VariablesQbIncrementPosition (double step)

void	ConstraintsBiReset ()

void	ConstraintsBiLoad_C (double factor=1, double recovery_clamp=0.1, bool do_clamp=false)

void	ConstraintsBiLoad_Ct (double factor=1)

void	ConstraintsBiLoad_Qc (double factor=1)

void	ConstraintsFbLoadForces (double factor=1)

void	ConstraintsFetch_react (double factor=1)

virtual int	GetNcoords_x () override
	Tells the number of position coordinates x in y = {x, v}.

virtual int	GetNcoords_v () override
	Tells the number of speed coordinates of v in y = {x, v} and dy/dt={v, a}.

virtual int	GetNconstr () override
	Tells the number of lagrangian multipliers (constraints)

virtual void	StateGather (ChState &x, ChStateDelta &v, double &T) override
	From system to state y={x,v}.

virtual void	StateScatter (const ChState &x, const ChStateDelta &v, const double T, bool full_update) override
	From state Y={x,v} to system. This also triggers an update operation.

virtual void	StateGatherAcceleration (ChStateDelta &a) override
	From system to state derivative (acceleration), some timesteppers might need last computed accel.

virtual void	StateScatterAcceleration (const ChStateDelta &a) override
	From state derivative (acceleration) to system, sometimes might be needed.

virtual void	StateGatherReactions (ChVectorDynamic<> &L) override
	From system to reaction forces (last computed) - some timestepper might need this.

virtual void	StateScatterReactions (const ChVectorDynamic<> &L) override
	From reaction forces to system, ex. store last computed reactions in ChLink objects for plotting etc.

virtual void	StateIncrementX (ChState &x_new, const ChState &x, const ChStateDelta &Dx) override
	Perform x_new = x + dx, for x in Y = {x, dx/dt}. More...

virtual bool	StateSolveCorrection (ChStateDelta &Dv, ChVectorDynamic<> &L, const ChVectorDynamic<> &R, const ChVectorDynamic<> &Qc, const double c_a, const double c_v, const double c_x, const ChState &x, const ChStateDelta &v, const double T, bool force_state_scatter, bool full_update, bool force_setup) override
	Assuming a DAE of the form. More...

virtual void	LoadResidual_F (ChVectorDynamic<> &R, const double c) override
	Increment a vector R with the term cF: R += cF. More...

virtual void	LoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
	Increment a vector R with a term that has M multiplied a given vector w: R += cMw. More...

virtual void	LoadResidual_CqL (ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c) override
	Increment a vectorR with the term Cq'L: R += cCq'*L. More...

virtual void	LoadConstraint_C (ChVectorDynamic<> &Qc, const double c, const bool do_clamp=false, const double clamp=1e30) override
	Increment a vector Qc with the term C: Qc += c*C. More...

virtual void	LoadConstraint_Ct (ChVectorDynamic<> &Qc, const double c) override
	Increment a vector Qc with the term Ct = partial derivative dC/dt: Qc += c*Ct. More...

virtual void	CustomEndOfStep ()
	Executes custom processing at the end of step. More...

double	ComputeCollisions ()
	Perform the collision detection. More...

void	RegisterCustomCollisionCallback (std::shared_ptr< CustomCollisionCallback > callback)
	Specify a callback object to be invoked at each collision detection step. More...

void	UnregisterCustomCollisionCallback (std::shared_ptr< CustomCollisionCallback > callback)
	Remove the given collision callback from this system.

virtual void	SetCollisionSystemType (collision::ChCollisionSystemType type)
	Change the underlying collision detection system to the specified type. More...

virtual void	SetCollisionSystem (std::shared_ptr< collision::ChCollisionSystem > coll_sys)
	Change the underlying collision system. More...

std::shared_ptr< collision::ChCollisionSystem >	GetCollisionSystem () const
	Access the underlying collision system. More...

virtual void	SetContactContainer (collision::ChCollisionSystemType type)
	Change the underlying contact container given the specified type of the collision detection system. More...

virtual void	SetContactContainer (std::shared_ptr< ChContactContainer > contactcontainer)
	Change the underlying contact container. More...

std::shared_ptr< ChContactContainer >	GetContactContainer () const
	Access the underlying contact container. More...

void	SetUseSleeping (bool ms)
	Turn on this feature to let the system put to sleep the bodies whose motion has almost come to a rest. More...

bool	GetUseSleeping () const
	Tell if the system will put to sleep the bodies whose motion has almost come to a rest.

int	DoStepDynamics (double step_size)
	Advances the dynamical simulation for a single step, of length step_size. More...

bool	DoFrameDynamics (double end_time)
	Performs integration until the m_endtime is exactly reached, but current time step may be automatically "retouched" to meet exactly the m_endtime after n steps. More...

bool	DoEntireDynamics (double end_time)
	Given the current state, the sw simulates the dynamical behavior of the system, until the end time is reached, repeating many steps (maybe the step size will be automatically changed if the integrator method supports step size adaption).

bool	DoEntireUniformDynamics (double end_time, double frame_step)
	Like "DoEntireDynamics", but results are provided at uniform steps "frame_step", using the DoFrameDynamics() many times.

size_t	GetStepcount () const
	Return the total number of time steps taken so far.

void	ResetStepcount ()
	Reset to 0 the total number of time steps.

int	GetSolverCallsCount () const
	Return the number of calls to the solver's Solve() function. More...

int	GetSolverSetupCount () const
	Return the number of calls to the solver's Setup() function. More...

void	EnableSolverMatrixWrite (bool val, const std::string &out_dir=".")
	Set this to "true" to enable automatic saving of solver matrices at each time step, for debugging purposes. More...

bool	IsSolverMatrixWriteEnabled () const

void	DumpSystemMatrices (bool save_M, bool save_K, bool save_R, bool save_Cq, const char *path)
	Dump the current M mass matrix, K damping matrix, R damping matrix, Cq constraint jacobian matrix (at the current configuration). More...

void	GetMassMatrix (ChSparseMatrix *M)
	Compute the system-level mass matrix. More...

void	GetStiffnessMatrix (ChSparseMatrix *K)
	Compute the system-level stiffness matrix, i.e. More...

void	GetDampingMatrix (ChSparseMatrix *R)
	Compute the system-level damping matrix, i.e. More...

void	GetConstraintJacobianMatrix (ChSparseMatrix *Cq)
	Compute the system-level constraint jacobian matrix, i.e. More...

bool	DoStepKinematics (double step_size)
	Advances the kinematic simulation for a single step of given length.

bool	DoFrameKinematics (double end_time)
	Performs kinematics until the end time is exactly reached. More...

bool	DoEntireKinematics (double end_time)
	Given the current state, this kinematic simulation satisfies all the constraints with the "DoStepKinematics" procedure for each time step, from the current time to the end time.

bool	DoAssembly (int action)
	Given the current time and state, attempt to satisfy all constraints, using a Newton-Raphson iteration loop. More...

bool	DoFullAssembly ()
	Shortcut for full position/velocity/acceleration assembly.

bool	DoStaticAnalysis (ChStaticAnalysis &analysis)
	Perform a generic static analysis. More...

bool	DoStaticLinear ()
	Solve the position of static equilibrium (and the reactions). More...

bool	DoStaticNonlinear (int nsteps=10, bool verbose=false)
	Solve the position of static equilibrium (and the reactions). More...

bool	DoStaticNonlinearRheonomic (int nsteps=10, bool verbose=false, std::shared_ptr< ChStaticNonLinearRheonomicAnalysis::IterationCallback > callback=nullptr)
	Solve the position of static equilibrium (and the reactions). More...

bool	DoStaticRelaxing (int nsteps=10)
	Finds the position of static equilibrium (and the reactions) starting from the current position. More...

virtual void	ArchiveOUT (ChArchiveOut &marchive)
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIN (ChArchiveIn &marchive)
	Method to allow deserialization of transient data from archives.

int	FileProcessChR (ChStreamInBinary &m_file)
	Process a ".chr" binary file containing the full system object hierarchy as exported -for example- by the R3D modeler, with chrono plug-in version, or by using the FileWriteChR() function.

int	FileWriteChR (ChStreamOutBinary &m_file)
	Write a ".chr" binary file containing the full system object hierarchy (bodies, forces, links, etc.) (deprecated function - obsolete)

Public Member Functions inherited from chrono::ChIntegrableIIorder
virtual int	GetNcoords_a ()
	Return the number of acceleration coordinates of a in dy/dt={v, a} This is a default implementation that works in almost all cases, as dim(a) = dim(v),.

virtual void	StateSetup (ChState &x, ChStateDelta &v, ChStateDelta &a)
	Set up the system state with separate II order components x, v, a for y = {x, v} and dy/dt={v, a}.

virtual bool	StateSolveA (ChStateDelta &Dvdt, ChVectorDynamic<> &L, const ChState &x, const ChStateDelta &v, const double T, const double dt, bool force_state_scatter, bool full_update)
	Solve for accelerations: a = f(x,v,t) Given current state y={x,v} , computes acceleration a in the state derivative dy/dt={v,a} and lagrangian multipliers L (if any). More...

virtual int	GetNcoords_y () override
	Return the number of coordinates in the state Y. More...

virtual int	GetNcoords_dy () override
	Return the number of coordinates in the state increment. More...

virtual void	StateGather (ChState &y, double &T) override
	Gather system state in specified array. More...

virtual void	StateScatter (const ChState &y, const double T, bool full_update) override
	Scatter the states from the provided array to the system. More...

virtual void	StateGatherDerivative (ChStateDelta &Dydt) override
	Gather from the system the state derivatives in specified array. More...

virtual void	StateScatterDerivative (const ChStateDelta &Dydt) override
	Scatter the state derivatives from the provided array to the system. More...

virtual void	StateIncrement (ChState &y_new, const ChState &y, const ChStateDelta &Dy) override
	Increment state array: y_new = y + Dy. More...

virtual bool	StateSolve (ChStateDelta &dydt, ChVectorDynamic<> &L, const ChState &y, const double T, const double dt, bool force_state_scatter, bool full_update) override
	Solve for state derivatives: dy/dt = f(y,t). More...

virtual bool	StateSolveCorrection (ChStateDelta &Dy, ChVectorDynamic<> &L, const ChVectorDynamic<> &R, const ChVectorDynamic<> &Qc, const double a, const double b, const ChState &y, const double T, const double dt, bool force_state_scatter, bool full_update, bool force_setup) override final
	Override of method for Ist order implicit integrators. More...

Public Member Functions inherited from chrono::ChIntegrable
virtual void	StateSetup (ChState &y, ChStateDelta &dy)
	Set up the system state.

virtual void	LoadResidual_Hv (ChVectorDynamic<> &R, const ChVectorDynamic<> &v, const double c)
	Increment a vector R (usually the residual in a Newton Raphson iteration for solving an implicit integration step) with a term that has H multiplied a given vector w: R += cHw. More...

Protected Member Functions
virtual void	DescriptorPrepareInject (ChSystemDescriptor &mdescriptor)
	Pushes all ChConstraints and ChVariables contained in links, bodies, etc. into the system descriptor.

void	SetupInitial ()
	Initial system setup before analysis. More...

virtual ChVector	GetBodyAppliedForce (ChBody *body)
	Return the resultant applied force on the specified body. More...

virtual ChVector	GetBodyAppliedTorque (ChBody *body)
	Return the resultant applied torque on the specified body. More...

Protected Attributes
ChAssembly	assembly

std::shared_ptr< ChContactContainer >	contact_container
	the container of contacts

ChVector	G_acc
	gravitational acceleration

bool	is_initialized
	if false, an initial setup is required (i.e. a call to SetupInitial)

bool	is_updated
	if false, a new update is required (i.e. a call to Update)

int	ncoords
	number of scalar coordinates (including 4th dimension of quaternions) for all active bodies

int	ndoc
	number of scalar constraints (including constr. on quaternions)

int	nsysvars
	number of variables (coords+lagrangian mult.), i.e. = ncoords+ndoc for all active bodies

int	ncoords_w
	number of scalar coordinates when using 3 rot. dof. per body; for all active bodies

int	ndoc_w
	number of scalar constraints when using 3 rot. dof. per body; for all active bodies

int	nsysvars_w
	number of variables when using 3 rot. dof. per body; i.e. = ncoords_w+ndoc_w

int	ndof
	number of degrees of freedom, = ncoords-ndoc = ncoords_w-ndoc_w ,

int	ndoc_w_C
	number of scalar constraints C, when using 3 rot. dof. per body (excluding unilaterals)

int	ndoc_w_D
	number of scalar constraints D, when using 3 rot. dof. per body (only unilaterals)

double	ch_time
	simulation time of the system

double	step
	time step

double	tol_force
	tolerance for forces (used to obtain a tolerance for impulses)

int	maxiter
	max iterations for nonlinear convergence in DoAssembly()

bool	use_sleeping
	if true, put to sleep objects that come to rest

std::shared_ptr< ChSystemDescriptor >	descriptor
	system descriptor

std::shared_ptr< ChSolver >	solver
	solver for DVI or DAE problem

double	min_bounce_speed
	minimum speed for rebounce after impacts. Lower speeds are clamped to 0

double	max_penetration_recovery_speed
	limit for the speed of penetration recovery (positive, speed of exiting)

size_t	stepcount
	internal counter for steps

int	setupcount
	number of calls to the solver's Setup()

int	solvecount
	number of StateSolveCorrection (reset to 0 at each timestep of static analysis)

bool	write_matrix
	write current system matrix to file(s); for debugging

std::string	output_dir
	output directory for writing system matrices

int	ncontacts
	total number of contacts

collision::ChCollisionSystemType	collision_system_type
	type of the collision engine

std::shared_ptr< collision::ChCollisionSystem >	collision_system
	collision engine

std::vector< std::shared_ptr< CustomCollisionCallback > >	collision_callbacks
	user-defined collision callbacks

std::unique_ptr< ChMaterialCompositionStrategy >	composition_strategy

ChVisualSystem *	visual_system
	material composition strategy More...

int	nthreads_chrono

int	nthreads_eigen

int	nthreads_collision

ChTimer< double >	timer_step
	timer for integration step

ChTimer< double >	timer_advance
	timer for time integration

ChTimer< double >	timer_ls_solve
	timer for solver (excluding setup phase)

ChTimer< double >	timer_ls_setup
	timer for solver setup

ChTimer< double >	timer_jacobian
	timer for computing/loading Jacobian information

ChTimer< double >	timer_collision
	timer for collision detection

ChTimer< double >	timer_setup
	timer for system setup

ChTimer< double >	timer_update
	timer for system update

std::shared_ptr< ChTimestepper >	timestepper
	time-stepper object

bool	last_err
	indicates error over the last kinematic/dynamics/statics

ChVectorDynamic	applied_forces
	system-wide vector of applied forces (lazy evaluation)

bool	applied_forces_current
	indicates if system-wide vector of forces is up-to-date

Friends
class	ChAssembly

class	ChBody

class	fea::ChMesh

class	ChContactContainerNSC

class	ChContactContainerSMC

class	ChVisualSystem

class	modal::ChModalAssembly

Member Function Documentation

◆ Add()

void chrono::ChSystem::Add ( std::shared_ptr< ChPhysicsItem > item )

Attach an arbitrary ChPhysicsItem (e.g.

ChBody, ChParticles, ChLink, etc.) to the assembly. It will take care of adding it to the proper list of bodies, links, meshes, or generic physic item. (i.e. it calls AddBody, AddShaft(), AddLink(), AddMesh(), or AddOtherPhysicsItem()). Note, you cannot call Add() during an Update (i.e. items like particle generators that are already inserted in the assembly cannot call this) because not thread safe; instead, use AddBatch().

◆ AddBatch()

void chrono::ChSystem::AddBatch ( std::shared_ptr< ChPhysicsItem > item )

inline

Items added in this way are added like in the Add() method, but not instantly, they are simply queued in a batch of 'to add' items, that are added automatically at the first Setup() call.

This is thread safe.

◆ Clone()

virtual ChSystem* chrono::ChSystem::Clone ( ) const

pure virtual

"Virtual" copy constructor.

Concrete derived classes must implement this.

Implemented in chrono::ChSystemMulticoreSMC, chrono::ChSystemMulticoreNSC, chrono::ChSystemSMC, and chrono::ChSystemNSC.

◆ ComputeCollisions()

double chrono::ChSystem::ComputeCollisions ( )

Perform the collision detection.

New contacts are inserted in the ChContactContainer object(s), and old ones are removed. This is mostly called automatically by time integration.

◆ CustomEndOfStep()

virtual void chrono::ChSystem::CustomEndOfStep ( )

inlinevirtual

Executes custom processing at the end of step.

By default it does nothing, but if you inherit a special ChSystem you can implement this.

◆ DoAssembly()

bool chrono::ChSystem::DoAssembly ( int action )

Given the current time and state, attempt to satisfy all constraints, using a Newton-Raphson iteration loop.

Used iteratively in inverse kinematics. Action can be one of AssemblyLevel::POSITION, AssemblyLevel::VELOCITY, or AssemblyLevel::ACCELERATION (or a combination of these) Returns true if no errors and false if an error occurred (impossible assembly?)

◆ DoFrameDynamics()

bool chrono::ChSystem::DoFrameDynamics ( double end_time )

Performs integration until the m_endtime is exactly reached, but current time step may be automatically "retouched" to meet exactly the m_endtime after n steps.

Useful when you want to advance the simulation in a simulations (3d modeling software etc.) which needs updates of the screen at a fixed rate (ex.30th of second) while the integration must use more steps.

◆ DoFrameKinematics()

bool chrono::ChSystem::DoFrameKinematics ( double end_time )

Performs kinematics until the end time is exactly reached.

The current time step may be automatically adjusted to meet exactly the m_endtime after n steps.

◆ DoStaticAnalysis()

bool chrono::ChSystem::DoStaticAnalysis ( ChStaticAnalysis & analysis )

Perform a generic static analysis.

Low level API, where the user creates and configures a ChStaticAnalysis-inherited object by his own. For ready-to-use analysis, use DoStaticLinear, DoStaticNonLinear, DoStaticNonlinearRheonomic etc. instead.

◆ DoStaticLinear()

bool chrono::ChSystem::DoStaticLinear ( )

Solve the position of static equilibrium (and the reactions).

This is a one-step only approach that solves the linear equilibrium. Appropriate mostly for FEM problems with small deformations.

◆ DoStaticNonlinear()

bool chrono::ChSystem::DoStaticNonlinear	(	int	nsteps = `10`,
		bool	verbose = `false`
	)

Solve the position of static equilibrium (and the reactions).

This function solves the equilibrium for the nonlinear problem (large displacements). This version uses a nonlinear static analysis solver with default parameters.

◆ DoStaticNonlinearRheonomic()

bool chrono::ChSystem::DoStaticNonlinearRheonomic	(	int	nsteps = `10`,
		bool	verbose = `false`,
		std::shared_ptr< ChStaticNonLinearRheonomicAnalysis::IterationCallback >	callback = `nullptr`
	)

Solve the position of static equilibrium (and the reactions).

This function solves the equilibrium for the nonlinear problem (large displacements), but differently from DoStaticNonlinear, it considers rheonomic constraints (ex. ChLinkMotorRotationSpeed) that can impose steady-state speeds&accelerations to the mechanism, ex. to generate centrifugal forces in turbine blades. This version uses a nonlinear static analysis solver with default parameters.

◆ DoStaticRelaxing()

bool chrono::ChSystem::DoStaticRelaxing ( int nsteps = 10 )

Finds the position of static equilibrium (and the reactions) starting from the current position.

Since a truncated iterative method is used, you may need to call this method multiple times in case of large nonlinearities before coming to the precise static solution.

◆ DoStepDynamics()

int chrono::ChSystem::DoStepDynamics ( double step_size )

Advances the dynamical simulation for a single step, of length step_size.

This function is typically called many times in a loop in order to simulate up to a desired end time.

◆ DumpSystemMatrices()

void chrono::ChSystem::DumpSystemMatrices	(	bool	save_M,
		bool	save_K,
		bool	save_R,
		bool	save_Cq,
		const char *	path
	)

Dump the current M mass matrix, K damping matrix, R damping matrix, Cq constraint jacobian matrix (at the current configuration).

These can be later used for linearized motion, modal analysis, buckling analysis, etc. The name of the files will be [path]_M.dat [path]_K.dat [path]_R.dat [path]_Cq.dat Might throw ChException if file can't be saved.

◆ EnableSolverMatrixWrite()

void chrono::ChSystem::EnableSolverMatrixWrite	(	bool	val,
		const std::string &	out_dir = `"."`
	)

Set this to "true" to enable automatic saving of solver matrices at each time step, for debugging purposes.

Note that matrices will be saved in the working directory of the exe, with format 0001_01_H.dat 0002_01_H.dat (if the timestepper requires multiple solves, also 0001_01. 0001_02.. etc.) The matrices being saved are: dump_Z.dat has the assembled optimization matrix (Matlab sparse format) dump_rhs.dat has the assembled RHS dump_H.dat has usually H=M (mass), but could be also H=a*M+b*K+c*R or such. (Matlab sparse format) dump_Cq.dat has the jacobians (Matlab sparse format) dump_E.dat has the constr.compliance (Matlab sparse format) dump_f.dat has the applied loads dump_b.dat has the constraint rhs as passed to the solver in the problem

 | H -Cq'|*|q|- | f|= |0|
 | Cq -E | |l|  |-b|  |c|

where l \(\in Y, c \in Ny\), normal cone to Y Enable/disable debug output of system matrices.

◆ FlushBatch()

void chrono::ChSystem::FlushBatch ( )

inline

If some items are queued for addition in the assembly, using AddBatch(), this will effectively add them and clean the batch.

Called automatically at each Setup().

◆ ForceUpdate()

void chrono::ChSystem::ForceUpdate ( )

In normal usage, no system update is necessary at the beginning of a new dynamics step (since an update is performed at the end of a step).

However, this is not the case if external changes to the system are made. Most such changes are discovered automatically (addition/removal of items, input of mesh loads). For special cases, this function allows the user to trigger a system update at the beginning of the step immediately following this call.

◆ GetBodyAppliedForce()

ChVector chrono::ChSystem::GetBodyAppliedForce ( ChBody * body )

protectedvirtual

Return the resultant applied force on the specified body.

This resultant force includes all external applied loads acting on the body (from gravity, loads, springs, etc). However, this does not include any constraint forces. In particular, contact forces are not included if using the NSC formulation, but are included when using the SMC formulation.

Reimplemented in chrono::ChSystemMulticore.

◆ GetBodyAppliedTorque()

ChVector chrono::ChSystem::GetBodyAppliedTorque ( ChBody * body )

protectedvirtual

Return the resultant applied torque on the specified body.

This resultant torque includes all external applied loads acting on the body (from gravity, loads, springs, etc). However, this does not include any constraint forces. In particular, contact torques are not included if using the NSC formulation, but are included when using the SMC formulation.

Reimplemented in chrono::ChSystemMulticore.

◆ GetCollisionSystem()

std::shared_ptr<collision::ChCollisionSystem> chrono::ChSystem::GetCollisionSystem ( ) const

inline

Access the underlying collision system.

Usually this is not needed, as the collision system is automatically handled by the ChSystem.

◆ GetConstraintJacobianMatrix()

void chrono::ChSystem::GetConstraintJacobianMatrix ( ChSparseMatrix * Cq )

Compute the system-level constraint jacobian matrix, i.e.

the jacobian Cq=-dC/dq where C are constraints (the lower left part of the KKT matrix). This function has a small overhead, because it must assembly the sparse matrix -which is used only for the purpose of this function. fill this system damping matrix

◆ GetContactContainer()

std::shared_ptr<ChContactContainer> chrono::ChSystem::GetContactContainer ( ) const

inline

Access the underlying contact container.

Usually this is not needed, as the contact container is automatically handled by the ChSystem.

◆ GetContactMethod()

virtual ChContactMethod chrono::ChSystem::GetContactMethod ( ) const

pure virtual

Return the contact method supported by this system.

Contactables (bodies, FEA nodes, FEA traiangles, etc.) added to this system must be compatible.

Implemented in chrono::ChSystemNSC, chrono::ChSystemMulticoreSMC, chrono::ChSystemMulticoreNSC, and chrono::ChSystemSMC.

◆ GetDampingMatrix()

void chrono::ChSystem::GetDampingMatrix ( ChSparseMatrix * R )

Compute the system-level damping matrix, i.e.

the jacobian -dF/dv where F are stiff loads. Note that not all loads provide a jacobian, as this is optional in their implementation. This function has a small overhead, because it must assembly the sparse matrix -which is used only for the purpose of this function. fill this system damping matrix

◆ GetMassMatrix()

void chrono::ChSystem::GetMassMatrix ( ChSparseMatrix * M )

Compute the system-level mass matrix.

This function has a small overhead, because it must assembly the sparse matrix -which is used only for the purpose of this function. fill this system mass matrix

◆ GetSolverCallsCount()

int chrono::ChSystem::GetSolverCallsCount ( ) const

inline

Return the number of calls to the solver's Solve() function.

This counter is reset at each timestep.

◆ GetSolverMaxIterations()

int chrono::ChSystem::GetSolverMaxIterations ( ) const

Get the current maximum number of iterations, if using an iterative solver.

Deprecated:: Prefer using GetSolver and accessing solver statistics directly.

◆ GetSolverSetupCount()

int chrono::ChSystem::GetSolverSetupCount ( ) const

inline

Return the number of calls to the solver's Setup() function.

This counter is reset at each timestep.

◆ GetStiffnessMatrix()

void chrono::ChSystem::GetStiffnessMatrix ( ChSparseMatrix * K )

Compute the system-level stiffness matrix, i.e.

the jacobian -dF/dq where F are stiff loads. Note that not all loads provide a jacobian, as this is optional in their implementation. This function has a small overhead, because it must assembly the sparse matrix -which is used only for the purpose of this function. fill this system stiffness matrix

◆ GetTimerLSsolve()

virtual double chrono::ChSystem::GetTimerLSsolve ( ) const

inlinevirtual

Return the time (in seconds) for the solver, within the time step.

Note that this time excludes any calls to the solver's Setup function.

Reimplemented in chrono::ChSystemMulticore.

◆ LoadConstraint_C()

void chrono::ChSystem::LoadConstraint_C	(	ChVectorDynamic<> &	Qc,
		const double	c,
		const bool	do_clamp = `false`,
		const double	clamp = `1e30`
	)

overridevirtual

Increment a vector Qc with the term C: Qc += c*C.

Parameters

Qc	result: the Qc residual, Qc += c*C
c	a scaling factor
do_clamp	enable optional clamping of Qc
clamp	clamping value

Reimplemented from chrono::ChIntegrableIIorder.

◆ LoadConstraint_Ct()

void chrono::ChSystem::LoadConstraint_Ct	(	ChVectorDynamic<> &	Qc,
		const double	c
	)

overridevirtual

Increment a vector Qc with the term Ct = partial derivative dC/dt: Qc += c*Ct.

Parameters

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

Reimplemented from chrono::ChIntegrableIIorder.

◆ LoadResidual_CqL()

void chrono::ChSystem::LoadResidual_CqL	(	ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	L,
		const double	c
	)

overridevirtual

Increment a vectorR with the term Cq'*L: R += c*Cq'*L.

Parameters

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

Reimplemented from chrono::ChIntegrableIIorder.

◆ LoadResidual_F()

void chrono::ChSystem::LoadResidual_F	(	ChVectorDynamic<> &	R,
		const double	c
	)

overridevirtual

Increment a vector R with the term c*F: R += c*F.

Parameters

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

Reimplemented from chrono::ChIntegrableIIorder.

◆ LoadResidual_Mv()

void chrono::ChSystem::LoadResidual_Mv	(	ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	w,
		const double	c
	)

overridevirtual

Increment a vector R with a term that has M multiplied a given vector w: R += c*M*w.

Parameters

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

Reimplemented from chrono::ChIntegrableIIorder.

◆ NewBody()

ChBody * chrono::ChSystem::NewBody ( )

virtual

Create and return the pointer to a new body.

The body is consistent with the type of the collision system currently associated with this ChSystem. Note that the body is not attached to this system.

Reimplemented in chrono::ChSystemDistributed, and chrono::ChSystemMulticore.

◆ NewBodyAuxRef()

ChBodyAuxRef * chrono::ChSystem::NewBodyAuxRef ( )

virtual

Create and return the pointer to a new body with auxiliary reference frame.

The body is consistent with the type of the collision system currently associated with this ChSystem. Note that the body is not attached to this system.

Reimplemented in chrono::ChSystemDistributed, and chrono::ChSystemMulticore.

◆ Reference_LM_byID()

void chrono::ChSystem::Reference_LM_byID ( )

Given inserted markers and links, restores the pointers of links to markers given the information about the marker IDs.

Will be made obsolete in future with new serialization systems.

◆ RegisterCustomCollisionCallback()

void chrono::ChSystem::RegisterCustomCollisionCallback ( std::shared_ptr< CustomCollisionCallback > callback )

Specify a callback object to be invoked at each collision detection step.

Multiple such callback objects can be registered with a system. If present, their OnCustomCollision() method is invoked. Use this if you want that some specific callback function is executed at each collision detection step (ex. all the times that ComputeCollisions() is automatically called by the integration method). For example some other collision engine could add further contacts using this callback.

◆ SetCollisionSystem()

void chrono::ChSystem::SetCollisionSystem ( std::shared_ptr< collision::ChCollisionSystem > coll_sys )

virtual

Change the underlying collision system.

By default, a ChSystem uses a Bullet-based collision detection engine.

◆ SetCollisionSystemType()

void chrono::ChSystem::SetCollisionSystemType ( collision::ChCollisionSystemType type )

virtual

Change the underlying collision detection system to the specified type.

By default, a ChSystem uses a Bullet-based collision detection engine (collision::ChCollisionSystemType::BULLET).

Reimplemented in chrono::ChSystemMulticoreSMC, and chrono::ChSystemMulticore.

◆ SetContactContainer() [1/2]

virtual void chrono::ChSystem::SetContactContainer ( collision::ChCollisionSystemType type )

inlinevirtual

Change the underlying contact container given the specified type of the collision detection system.

Usually this is not needed, as the contact container is automatically handled by the ChSystem. The default implementation is a no-op, since the default contact container for a ChSystem is suitable for all types of supported collision detection systems.

Reimplemented in chrono::ChSystemMulticoreSMC, and chrono::ChSystemMulticoreNSC.

◆ SetContactContainer() [2/2]

void chrono::ChSystem::SetContactContainer ( std::shared_ptr< ChContactContainer > contactcontainer )

virtual

Change the underlying contact container.

The contact container collects information from the underlying collision detection system required for contact force generation. Usually this is not needed, as the contact container is automatically handled by the ChSystem. Make sure the provided contact container is compatible with both the collision detection system and the contact force formulation (NSC or SMC).

Reimplemented in chrono::ChSystemMulticoreSMC, chrono::ChSystemMulticoreNSC, chrono::ChSystemSMC, and chrono::ChSystemNSC.

◆ SetMaxiter()

void chrono::ChSystem::SetMaxiter ( int m_maxiter )

inline

Sets outer iteration limit for assembly constraints.

When trying to keep constraints together, the iterative process is stopped if this max.number of iterations (or tolerance) is reached.

◆ SetMaxPenetrationRecoverySpeed()

void chrono::ChSystem::SetMaxPenetrationRecoverySpeed ( double mval )

inline

For the default stepper, you can limit the speed of exiting from penetration situations.

Usually set a positive value, about 0.1 .. 2 . (as exiting speed, in m/s)

◆ SetMinBounceSpeed()

void chrono::ChSystem::SetMinBounceSpeed ( double mval )

inline

For elastic collisions, with objects that have nonzero restitution coefficient: objects will rebounce only if their relative colliding speed is above this threshold.

Default 0.15 m/s. If this is too low, aliasing problems can happen with small high frequency rebounces, and settling to static stacking might be more difficult.

◆ SetNumThreads()

void chrono::ChSystem::SetNumThreads	(	int	num_threads_chrono,
		int	num_threads_collision = `0`,
		int	num_threads_eigen = `0`
	)

virtual

Set the number of OpenMP threads used by Chrono itself, Eigen, and the collision detection system.

  num_threads_chrono    - used in FEA (parallel evaluation of internal forces and Jacobians) and
                          in SCM deformable terrain calculations.
  num_threads_collision - used in parallelization of collision detection (if applicable).
                          If passing 0, then num_threads_collision = num_threads_chrono.
  num_threads_eigen     - used in the Eigen sparse direct solvers and a few linear algebra operations.
                          Note that Eigen enables multi-threaded execution only under certain size conditions.
                          See the Eigen documentation.
                          If passing 0, then num_threads_eigen = num_threads_chrono.
By default (if this function is not called), the following values are used:
  num_threads_chrono = omp_get_num_procs()
  num_threads_collision = 1
  num_threads_eigen = 1

Note that a derived class may ignore some or all of these settings.

Reimplemented in chrono::ChSystemMulticore.

◆ SetSolverForceTolerance()

void chrono::ChSystem::SetSolverForceTolerance ( double tolerance )

inline

Set a solver tolerance threshold at force level (default: not specified).

Specify this value only if solving the problem at velocity level (e.g. solving a DVI problem). If this tolerance is specified, it is multiplied by the current integration stepsize and overwrites the current solver tolerance. By default, this tolerance is invalid and hence the solver's own tolerance threshold is used.

◆ SetSolverMaxIterations()

void chrono::ChSystem::SetSolverMaxIterations ( int max_iters )

Set the maximum number of iterations, if using an iterative solver.

Deprecated:: Prefer using SetSolver and setting solver parameters directly.

◆ SetSolverTolerance()

void chrono::ChSystem::SetSolverTolerance ( double tolerance )

Set the solver tolerance threshold (used with iterative solvers only).

Note that the stopping criteria differs from solver to solver.

◆ SetSolverType()

void chrono::ChSystem::SetSolverType ( ChSolver::Type type )

Choose the solver type, to be used for the simultaneous solution of the constraints in dynamical simulations (as well as in kinematics, statics, etc.)

Suggested solver for speed, but lower precision: PSOR
Suggested solver for higher precision: BARZILAIBORWEIN or APGD
For problems that involve a stiffness matrix: GMRES, MINRES

Notes:

This function is a shortcut, internally equivalent to a call to SetSolver().
Only a subset of available Chrono solvers can be set through this mechanism.
Prefer explicitly creating a solver, setting solver parameters, and then attaching the solver with SetSolver.

Deprecated:: This function does not support all available Chrono solvers. Prefer using SetSolver.

◆ SetStep()

void chrono::ChSystem::SetStep ( double m_step )

inline

Sets the time step used for integration (dynamical simulation).

The lower this value, the more precise the simulation. Usually, values about 0.01 s are enough for simple simulations. It may be modified automatically by integration methods, if they support automatic time adaption.

◆ SetTimestepperType()

void chrono::ChSystem::SetTimestepperType ( ChTimestepper::Type type )

Set the method for time integration (time stepper type).

Suggested for fast dynamics with hard (NSC) contacts: EULER_IMPLICIT_LINEARIZED
Suggested for fast dynamics with hard (NSC) contacts and low inter-penetration: EULER_IMPLICIT_PROJECTED
Suggested for finite element smooth dynamics: HHT, EULER_IMPLICIT_LINEARIZED

Notes:

for more advanced customization, use SetTimestepper()
old methods ANITESCU and TASORA were replaced by EULER_IMPLICIT_LINEARIZED and EULER_IMPLICIT_PROJECTED, respectively

◆ Setup()

void chrono::ChSystem::Setup ( )

virtual

Counts the number of bodies and links.

Computes the offsets of object states in the global state. Assumes that offset_x, offset_w, and offset_L are already set as starting point for offsetting all the contained sub objects.

Reimplemented in chrono::ChSystemMulticoreSMC, and chrono::ChSystemMulticore.

◆ SetupInitial()

void chrono::ChSystem::SetupInitial ( )

protected

Initial system setup before analysis.

This function performs an initial system setup, once system construction is completed and before an analysis.

◆ SetUseSleeping()

void chrono::ChSystem::SetUseSleeping ( bool ms )

inline

Turn on this feature to let the system put to sleep the bodies whose motion has almost come to a rest.

This feature will allow faster simulation of large scenarios for real-time purposes, but it will affect the precision! This functionality can be turned off selectively for specific ChBodies.

◆ ShowHierarchy()

void chrono::ChSystem::ShowHierarchy	(	ChStreamOutAscii &	m_file,
		int	level = `0`
	)		const

inline

Write the hierarchy of contained bodies, markers, etc.

in ASCII readable form, mostly for debugging purposes. Level is the tab spacing at the left.

◆ StateIncrementX()

void chrono::ChSystem::StateIncrementX	(	ChState &	x_new,
		const ChState &	x,
		const ChStateDelta &	Dx
	)

overridevirtual

Perform x_new = x + dx, for x in Y = {x, dx/dt}.

It takes care of the fact that x has quaternions, dx has angular vel etc. NOTE: the system is not updated automatically after the state increment, so one might need to call StateScatter() if needed.

Parameters

x_new	resulting x_new = x + Dx
x	initial state x
Dx	state increment Dx

Reimplemented from chrono::ChIntegrableIIorder.

◆ StateSolveCorrection()

bool chrono::ChSystem::StateSolveCorrection	(	ChStateDelta &	Dv,
		ChVectorDynamic<> &	L,
		const ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	Qc,
		const double	c_a,
		const double	c_v,
		const double	c_x,
		const ChState &	x,
		const ChStateDelta &	v,
		const double	T,
		bool	force_state_scatter,
		bool	full_update,
		bool	force_setup
	)

overridevirtual

Assuming a DAE of the form.

      M*a = F(x,v,t) + Cq'*L
      C(x,t) = 0

this function computes the solution of the change Du (in a or v or x) for a Newton iteration within an implicit integration scheme.

 |Du| = [ G   Cq' ]^-1 * | R |
 |DL|   [ Cq  0   ]      | Qc|

for residual R and G = [ c_a*M + c_v*dF/dv + c_x*dF/dx ].
This function returns true if successful and false otherwise.

Parameters

Dv	result: computed Dv
L	result: computed lagrangian multipliers, if any
R	the R residual
Qc	the Qc residual
c_a	the factor in c_a*M
c_v	the factor in c_v*dF/dv
c_x	the factor in c_x*dF/dv
x	current state, x part
v	current state, v part
T	current time T
force_state_scatter	if false, x and v are not scattered to the system
full_update	if true, perform a full update during scatter
force_setup	if true, call the solver's Setup() function

Reimplemented from chrono::ChIntegrableIIorder.

Member Data Documentation

◆ visual_system

ChVisualSystem* chrono::ChSystem::visual_system

protected

material composition strategy

run-time visualization engine

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

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

Description

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Member Function Documentation

◆ Add()

◆ AddBatch()

◆ Clone()

◆ ComputeCollisions()

◆ CustomEndOfStep()

◆ DoAssembly()

◆ DoFrameDynamics()

◆ DoFrameKinematics()

◆ DoStaticAnalysis()

◆ DoStaticLinear()

◆ DoStaticNonlinear()

◆ DoStaticNonlinearRheonomic()

◆ DoStaticRelaxing()

◆ DoStepDynamics()

◆ DumpSystemMatrices()

◆ EnableSolverMatrixWrite()

◆ FlushBatch()

◆ ForceUpdate()

◆ GetBodyAppliedForce()

◆ GetBodyAppliedTorque()

◆ GetCollisionSystem()

◆ GetConstraintJacobianMatrix()

◆ GetContactContainer()

◆ GetContactMethod()

◆ GetDampingMatrix()

◆ GetMassMatrix()

◆ GetSolverCallsCount()

◆ GetSolverMaxIterations()

◆ GetSolverSetupCount()

◆ GetStiffnessMatrix()

◆ GetTimerLSsolve()

◆ LoadConstraint_C()

◆ LoadConstraint_Ct()

◆ LoadResidual_CqL()

◆ LoadResidual_F()

◆ LoadResidual_Mv()

◆ NewBody()

◆ NewBodyAuxRef()

◆ Reference_LM_byID()

◆ RegisterCustomCollisionCallback()

◆ SetCollisionSystem()

◆ SetCollisionSystemType()

◆ SetContactContainer() [1/2]

◆ SetContactContainer() [2/2]

◆ SetMaxiter()

◆ SetMaxPenetrationRecoverySpeed()

◆ SetMinBounceSpeed()

◆ SetNumThreads()

◆ SetSolverForceTolerance()

◆ SetSolverMaxIterations()

◆ SetSolverTolerance()

◆ SetSolverType()

◆ SetStep()

◆ SetTimestepperType()

◆ Setup()

◆ SetupInitial()

◆ SetUseSleeping()

◆ ShowHierarchy()

◆ StateIncrementX()

◆ StateSolveCorrection()

Member Data Documentation

◆ visual_system