Description

Class for assemblies of items, for example ChBody, ChLink, ChMesh, etc.

Note that an assembly can be added to another assembly, to create a tree-like hierarchy. All positions of rigid bodies, FEA nodes, etc. are assumed with respect to the absolute frame.

#include <ChAssembly.h>

Inheritance diagram for chrono::ChAssembly:

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Collaboration diagram for chrono::ChAssembly:

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Public Member Functions
	ChAssembly (const ChAssembly &other)

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

void	Clear ()
	Removes all inserted items: bodies, links, etc.

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

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

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

void	RemoveAllBodies ()
	Remove all bodies from this assembly.

void	RemoveAllLinks ()
	Remove all links from this assembly.

void	RemoveAllMeshes ()
	Remove all meshes from this 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< 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< 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< ChPhysicsItem >	Search (const char *name)
	Search an item (body, link or other ChPhysics items) by name.

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

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.

int	GetNbodies () const
	Get the number of active bodies (so, 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 added to the assembly, including the grounded and sleeping bodies.

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).

virtual void	SetSystem (ChSystem *m_system) override
	Set the pointer to the parent ChSystem() and also add to new collision system / remove from old coll.system.

virtual void	SyncCollisionModels () override
	If this physical item contains one or more collision models, synchronize their coordinates and bounding boxes to the state of the item.

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

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

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

virtual void	SetNoSpeedNoAcceleration () override
	Set zero speed (and zero accelerations) in state, without changing the position.

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

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

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

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

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

virtual void	IntStateGather (const unsigned int off_x, ChState &x, const unsigned int off_v, ChStateDelta &v, double &T) override
	From item's state to global state vectors y={x,v} pasting the states at the specified offsets. More...

virtual void	IntStateScatter (const unsigned int off_x, const ChState &x, const unsigned int off_v, const ChStateDelta &v, const double T) override
	From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets. More...

virtual void	IntStateGatherAcceleration (const unsigned int off_a, ChStateDelta &a) override
	From item's state acceleration to global acceleration vector. More...

virtual void	IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a) override
	From global acceleration vector to item's state acceleration. More...

virtual void	IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L) override
	From item's reaction forces to global reaction vector. More...

virtual void	IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L) override
	From global reaction vector to item's reaction forces. More...

virtual void	IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv) override
	Computes x_new = x + Dt , using vectors at specified offsets. More...

virtual void	IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c) override
	Takes the F force term, scale and adds to R at given offset: R += c*F. More...

virtual void	IntLoadResidual_Mv (const unsigned int off, ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
	Takes the Mv term, multiplying mass by a vector, scale and adds to R at given offset: R += cM*w. More...

virtual void	IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c) override
	Takes the term Cq'L, scale and adds to R at given offset: R += cCq'*L. More...

virtual void	IntLoadConstraint_C (const unsigned int off, ChVectorDynamic<> &Qc, const double c, bool do_clamp, double recovery_clamp) override
	Takes the term C, scale and adds to Qc at given offset: Qc += c*C. More...

virtual void	IntLoadConstraint_Ct (const unsigned int off, ChVectorDynamic<> &Qc, const double c) override
	Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...

virtual void	IntToDescriptor (const unsigned int off_v, const ChStateDelta &v, const ChVectorDynamic<> &R, const unsigned int off_L, const ChVectorDynamic<> &L, const ChVectorDynamic<> &Qc) override
	Prepare variables and constraints to accommodate a solution: More...

virtual void	IntFromDescriptor (const unsigned int off_v, ChStateDelta &v, const unsigned int off_L, ChVectorDynamic<> &L) override
	After a solver solution, fetch values from variables and constraints into vectors: More...

virtual void	InjectVariables (ChSystemDescriptor &mdescriptor) override
	Tell to a system descriptor that there are variables of type ChVariables in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

virtual void	InjectConstraints (ChSystemDescriptor &mdescriptor) override
	Tell to a system descriptor that there are constraints of type ChConstraint in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

virtual void	ConstraintsLoadJacobians () override
	Adds the current jacobians in encapsulated ChConstraints.

virtual void	InjectKRMmatrices (ChSystemDescriptor &mdescriptor) override
	Tell to a system descriptor that there are items of type ChKblock in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

virtual void	KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor) override
	Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. More...

virtual void	VariablesFbReset () override
	Sets the 'fb' part (the known term) of the encapsulated ChVariables to zero.

virtual void	VariablesFbLoadForces (double factor=1) override
	Adds the current forces (applied to item) into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor.

virtual void	VariablesQbLoadSpeed () override
	Initialize the 'qb' part of the ChVariables with the current value of speeds. More...

virtual void	VariablesFbIncrementMq () override
	Adds M*q (masses multiplied current 'qb') to Fb, ex. More...

virtual void	VariablesQbSetSpeed (double step=0) override
	Fetches the item speed (ex. More...

virtual void	VariablesQbIncrementPosition (double step) override
	Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor. More...

virtual void	ConstraintsBiReset () override
	Sets to zero the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_C (double factor=1, double recovery_clamp=0.1, bool do_clamp=false) override
	Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_Ct (double factor=1) override
	Adds the current Ct (partial t-derivative, as in C_dt=0-> [Cq]*q_dt=-Ct) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_Qc (double factor=1) override
	Adds the current Qc (the vector of C_dtdt=0 -> [Cq]*q_dtdt=Qc ) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsFbLoadForces (double factor=1) override
	Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints.

virtual void	ConstraintsFetch_react (double factor=1) override
	Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...

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

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

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

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

ChSystem *	GetSystem () const
	Get the pointer to the parent ChSystem()

void	AddAsset (std::shared_ptr< ChAsset > masset)
	Add an optional asset (it can be used to define visualization shapes, es ChSphereShape, or textures, or custom attached properties that the user can define by creating his class inherited from ChAsset)

std::vector< std::shared_ptr< ChAsset > > &	GetAssets ()
	Access to the list of optional assets.

std::shared_ptr< ChAsset >	GetAssetN (unsigned int num)
	Access the Nth asset in the list of optional assets.

virtual ChFrame	GetAssetsFrame (unsigned int nclone=0)
	Get the master coordinate system for assets that have some geometric meaning. More...

virtual unsigned int	GetAssetsFrameNclones ()
	Optionally, a ChPhysicsItem can return multiple asset coordinate systems; this can be helpful if, for example, when a ChPhysicsItem contains 'clones' with the same assets (ex. More...

virtual bool	GetCollide () const
	Tell if the object is subject to collision. More...

virtual void	AddCollisionModelsToSystem ()
	If this physical item contains one or more collision models, add them to the system's collision engine.

virtual void	RemoveCollisionModelsFromSystem ()
	If this physical item contains one or more collision models, remove them from the system's collision engine.

virtual void	GetTotalAABB (ChVector<> &bbmin, ChVector<> &bbmax)
	Get the entire AABB axis-aligned bounding box of the object. More...

virtual void	GetCenter (ChVector<> &mcenter)
	Get a symbolic 'center' of the object. More...

virtual void	StreamINstate (ChStreamInBinary &mstream)
	Method to deserialize only the state (position, speed) Must be implemented by child classes.

virtual void	StreamOUTstate (ChStreamOutBinary &mstream)
	Method to serialize only the state (position, speed) Must be implemented by child classes.

unsigned int	GetOffset_x ()
	Get offset in the state vector (position part)

unsigned int	GetOffset_w ()
	Get offset in the state vector (speed part)

unsigned int	GetOffset_L ()
	Get offset in the lagrangian multipliers.

void	SetOffset_x (const unsigned int moff)
	Set offset in the state vector (position part) Note: only the ChSystem::Setup function should use this.

void	SetOffset_w (const unsigned int moff)
	Set offset in the state vector (speed part) Note: only the ChSystem::Setup function should use this.

void	SetOffset_L (const unsigned int moff)
	Set offset in the lagrangian multipliers Note: only the ChSystem::Setup function should use this.

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

int	GetIdentifier () const
	Gets the numerical identifier of the object.

void	SetIdentifier (int id)
	Sets the numerical identifier of the object.

double	GetChTime () const
	Gets the simulation time of this object.

void	SetChTime (double m_time)
	Sets the simulation time of this object.

const char *	GetName () const
	Gets the name of the object as C Ascii null-terminated string -for reading only!

void	SetName (const char myname[])
	Sets the name of this object, as ascii string.

std::string	GetNameString () const
	Gets the name of the object as C Ascii null-terminated string.

void	SetNameString (const std::string &myname)
	Sets the name of this object, as std::string.

void	MFlagsSetAllOFF (int &mflag)

void	MFlagsSetAllON (int &mflag)

void	MFlagSetON (int &mflag, int mask)

void	MFlagSetOFF (int &mflag, int mask)

int	MFlagGet (int &mflag, int mask)

virtual std::string &	ArchiveContainerName ()

Protected Attributes
std::vector< std::shared_ptr< ChBody > >	bodylist
	list of rigid bodies

std::vector< std::shared_ptr< ChLinkBase > >	linklist
	list of joints (links)

std::vector< std::shared_ptr< fea::ChMesh > >	meshlist
	list of meshes

std::vector< std::shared_ptr< ChPhysicsItem > >	otherphysicslist
	list of other physics objects

std::vector< std::shared_ptr< ChPhysicsItem > >	batch_to_insert
	list of items to insert at once

int	nbodies
	number of bodies (currently active)

int	nlinks
	number of links

int	nmeshes
	number of meshes

int	nphysicsitems
	number of other physics items

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)

int	nbodies_sleep
	number of bodies that are sleeping

int	nbodies_fixed
	number of bodies that are fixed

Protected Attributes inherited from chrono::ChPhysicsItem
ChSystem *	system
	parent system

std::vector< std::shared_ptr< ChAsset > >	assets
	set of assets

unsigned int	offset_x
	offset in vector of state (position part)

unsigned int	offset_w
	offset in vector of state (speed part)

unsigned int	offset_L
	offset in vector of lagrangian multipliers

Protected Attributes inherited from chrono::ChObj
double	ChTime
	the time of simulation for the object

Member Function Documentation

◆ Add()

void chrono::ChAssembly::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(), 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::ChAssembly::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.

This is thread safe.

◆ ConstraintsFetch_react()

void chrono::ChAssembly::ConstraintsFetch_react ( double factor = 1 )

overridevirtual

Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints.

Mostly used after the solver provided the solution in ChConstraints. Also, should convert the reactions obtained from dynamical simulation, from link space to intuitive react_force and react_torque.

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ FlushBatch()

void chrono::ChAssembly::FlushBatch ( )

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().

◆ IntFromDescriptor()

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

overridevirtual

After a solver solution, fetch values from variables and constraints into vectors:

Parameters

off_v	offset for v
v	vector to where the q 'unknowns' term of the variables will be copied
off_L	offset for L
L	vector to where L 'lagrangian ' term of the constraints will be copied

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntLoadConstraint_C()

void chrono::ChAssembly::IntLoadConstraint_C	(	const unsigned int	off,
		ChVectorDynamic<> &	Qc,
		const double	c,
		bool	do_clamp,
		double	recovery_clamp
	)

overridevirtual

Takes the term C, scale and adds to Qc at given offset: Qc += c*C.

Parameters

off	offset in Qc residual
Qc	result: the Qc residual, Qc += c*C
c	a scaling factor
do_clamp	apply clamping to c*C?
recovery_clamp	value for min/max clamping of c*C

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntLoadConstraint_Ct()

void chrono::ChAssembly::IntLoadConstraint_Ct	(	const unsigned int	off,
		ChVectorDynamic<> &	Qc,
		const double	c
	)

overridevirtual

Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct.

Parameters

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

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntLoadResidual_CqL()

void chrono::ChAssembly::IntLoadResidual_CqL	(	const unsigned int	off_L,
		ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	L,
		const double	c
	)

overridevirtual

Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L.

Parameters

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

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntLoadResidual_F()

void chrono::ChAssembly::IntLoadResidual_F	(	const unsigned int	off,
		ChVectorDynamic<> &	R,
		const double	c
	)

overridevirtual

Takes the F force term, scale and adds to R at given offset: R += c*F.

Parameters

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

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntLoadResidual_Mv()

void chrono::ChAssembly::IntLoadResidual_Mv	(	const unsigned int	off,
		ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	w,
		const double	c
	)

overridevirtual

Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w.

Parameters

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

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateGather()

void chrono::ChAssembly::IntStateGather	(	const unsigned int	off_x,
		ChState &	x,
		const unsigned int	off_v,
		ChStateDelta &	v,
		double &	T
	)

overridevirtual

From item's state to global state vectors y={x,v} pasting the states at the specified offsets.

Parameters

off_x	offset in x state vector
x	state vector, position part
off_v	offset in v state vector
v	state vector, speed part
T	time

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateGatherAcceleration()

void chrono::ChAssembly::IntStateGatherAcceleration	(	const unsigned int	off_a,
		ChStateDelta &	a
	)

overridevirtual

From item's state acceleration to global acceleration vector.

Parameters

off_a	offset in a accel. vector
a	acceleration part of state vector derivative

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateGatherReactions()

void chrono::ChAssembly::IntStateGatherReactions	(	const unsigned int	off_L,
		ChVectorDynamic<> &	L
	)

overridevirtual

From item's reaction forces to global reaction vector.

Parameters

off_L	offset in L vector
L	L vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateIncrement()

void chrono::ChAssembly::IntStateIncrement	(	const unsigned int	off_x,
		ChState &	x_new,
		const ChState &	x,
		const unsigned int	off_v,
		const ChStateDelta &	Dv
	)

overridevirtual

Computes x_new = x + Dt , using vectors at specified offsets.

By default, when DOF = DOF_w, it does just the sum, but in some cases (ex when using quaternions for rotations) it could do more complex stuff, and children classes might overload it.

Parameters

off_x	offset in x state vector
x_new	state vector, position part, incremented result
x	state vector, initial position part
off_v	offset in v state vector
Dv	state vector, increment

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateScatter()

void chrono::ChAssembly::IntStateScatter	(	const unsigned int	off_x,
		const ChState &	x,
		const unsigned int	off_v,
		const ChStateDelta &	v,
		const double	T
	)

overridevirtual

From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets.

Parameters

off_x	offset in x state vector
x	state vector, position part
off_v	offset in v state vector
v	state vector, speed part
T	time

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateScatterAcceleration()

void chrono::ChAssembly::IntStateScatterAcceleration	(	const unsigned int	off_a,
		const ChStateDelta &	a
	)

overridevirtual

From global acceleration vector to item's state acceleration.

Parameters

off_a	offset in a accel. vector
a	acceleration part of state vector derivative

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntStateScatterReactions()

void chrono::ChAssembly::IntStateScatterReactions	(	const unsigned int	off_L,
		const ChVectorDynamic<> &	L
	)

overridevirtual

From global reaction vector to item's reaction forces.

Parameters

off_L	offset in L vector
L	L vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ IntToDescriptor()

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

overridevirtual

Prepare variables and constraints to accommodate a solution:

Parameters

off_v	offset for v and R
v	vector that will be copied into the q 'unknowns' term of the variables (for warm starting)
R	vector that will be copied into the F 'force' term of the variables
off_L	offset for L and Qc
L	vector that will be copied into the L 'lagrangian ' term of the constraints (for warm starting)
Qc	vector that will be copied into the Qb 'constraint' term of the constraints

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ KRMmatricesLoad()

void chrono::ChAssembly::KRMmatricesLoad	(	double	Kfactor,
		double	Rfactor,
		double	Mfactor
	)

overridevirtual

Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any.

The K, R, M matrices are added with scaling values Kfactor, Rfactor, Mfactor. NOTE: signs are flipped respect to the ChTimestepper dF/dx terms: K = -dF/dq, R = -dF/dv

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ Setup()

void chrono::ChAssembly::Setup ( )

overridevirtual

Counts the number of bodies, links, and meshes.

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

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem, chrono::ChSystemParallelSMC, and chrono::ChSystemParallel.

◆ ShowHierarchy()

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

Writes the hierarchy of contained bodies, markers, etc.

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

◆ VariablesFbIncrementMq()

void chrono::ChAssembly::VariablesFbIncrementMq ( )

overridevirtual

Adds M*q (masses multiplied current 'qb') to Fb, ex.

if qb is initialized with v_old using VariablesQbLoadSpeed, this method can be used in timestepping schemes that do: M*v_new = M*v_old + forces*dt

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ VariablesQbIncrementPosition()

void chrono::ChAssembly::VariablesQbIncrementPosition ( double step )

overridevirtual

Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor.

pos+=qb*step If qb is a speed, this behaves like a single step of 1-st order numerical integration (Eulero integration).

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ VariablesQbLoadSpeed()

void chrono::ChAssembly::VariablesQbLoadSpeed ( )

overridevirtual

Initialize the 'qb' part of the ChVariables with the current value of speeds.

Note: since 'qb' is the unknown, this function seems unnecessary, unless used before VariablesFbIncrementMq()

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

◆ VariablesQbSetSpeed()

void chrono::ChAssembly::VariablesQbSetSpeed ( double step = 0 )

overridevirtual

Fetches the item speed (ex.

linear and angular vel.in rigid bodies) from the 'qb' part of the ChVariables and sets it as the current item speed. If 'step' is not 0, also should compute the approximate acceleration of the item using backward differences, that is accel=(new_speed-old_speed)/step. Mostly used after the solver provided the solution in ChVariables.

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::ChSystem.

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

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

Description

Public Member Functions

Protected Attributes

Member Function Documentation

◆ Add()

◆ AddBatch()

◆ ConstraintsFetch_react()

◆ FlushBatch()

◆ IntFromDescriptor()

◆ IntLoadConstraint_C()

◆ IntLoadConstraint_Ct()

◆ IntLoadResidual_CqL()

◆ IntLoadResidual_F()

◆ IntLoadResidual_Mv()

◆ IntStateGather()

◆ IntStateGatherAcceleration()

◆ IntStateGatherReactions()

◆ IntStateIncrement()

◆ IntStateScatter()

◆ IntStateScatterAcceleration()

◆ IntStateScatterReactions()

◆ IntToDescriptor()

◆ KRMmatricesLoad()

◆ Setup()

◆ ShowHierarchy()

◆ VariablesFbIncrementMq()

◆ VariablesQbIncrementPosition()

◆ VariablesQbLoadSpeed()

◆ VariablesQbSetSpeed()