Description

Class for assemblies of physical items.

This class is a container of ChPhysicsItems items i.e. rigid bodies, shafts, links, etc. ChAssembly objects can also contain other ChAssembly objects. Location and rotation of the contained ChPhysicsItems are assumed to be expressed 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).

ChAssembly &	operator= (ChAssembly other)
	Assignment operator for ChAssembly.

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

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

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

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

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

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...

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

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

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

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

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	RemoveAllShafts ()
	Remove all shafts 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 > > &	GetBodies () const
	Get the list of bodies.

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

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

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

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

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

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

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

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

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

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

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

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

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

unsigned int	GetNumBodies () const
	Get the total number of bodies added to the assembly, including fixed and sleeping bodies.

unsigned int	GetNumBodiesActive () const
	Get the number of active bodies, excluding sleeping or fixed.

unsigned int	GetNumBodiesSleeping () const
	Get the number of sleeping bodies.

unsigned int	GetNumBodiesFixed () const
	Get the number of bodies fixed to ground.

unsigned int	GetNumShafts () const
	Get the number of shafts.

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

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

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

unsigned int	GetNumLinks () const
	Get the number of links (including non active).

unsigned int	GetNumLinksActive () const
	Get the number of active links.

unsigned int	GetNumMeshes () const
	Get the number of meshes.

unsigned int	GetNumOtherPhysicsItems () const
	Get the number of other active physics items (including non active).

unsigned int	GetNumOtherPhysicsItemsActive () const
	Get the number of other active physics items.

virtual unsigned int	GetNumCoordsPosLevel () override
	Get the number of scalar coordinates at the position level. More...

virtual unsigned int	GetNumCoordsVelLevel () override
	Get the number of scalar coordinates at the velocity level.

virtual unsigned int	GetNumConstraints () override
	Get the number of scalar constraints in the assembly.

virtual unsigned int	GetNumConstraintsBilateral () override
	Get the number of scalar bilateral constraints in the assembly.

virtual unsigned int	GetNumConstraintsUnilateral () override
	Get the number of scalar unilateral constraints in the assembly.

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	AddCollisionModelsToSystem (ChCollisionSystem *coll_sys) const override
	Add collision models (if any) for all items in the assembly to the provided collision system.

virtual void	RemoveCollisionModelsFromSystem (ChCollisionSystem *coll_sys) const override
	Remove the collision models (if any) for all items in the assembly from the provided collision system.

virtual void	SyncCollisionModels () override
	Synchronize collision models for all physics items in this assembly.

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

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, bool full_update) 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	IntStateGetIncrement (const unsigned int off_x, const ChState &x_new, const ChState &x, const unsigned int off_v, ChStateDelta &Dv) override
	Computes Dt = x_new - x, 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	IntLoadLumpedMass_Md (const unsigned int off, ChVectorDynamic<> &Md, double &err, const double c) override
	Adds the lumped mass to a Md vector, representing a mass diagonal matrix. 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 &descriptor) override
	Register with the given system descriptor any ChVariable objects associated with this item.

virtual void	InjectConstraints (ChSystemDescriptor &descriptor) override
	Register with the given system descriptor any ChConstraint objects associated with this item.

virtual void	LoadConstraintJacobians () override
	Compute and load current Jacobians in encapsulated ChConstraint objects.

virtual void	InjectKRMMatrices (ChSystemDescriptor &descriptor) override
	Register with the given system descriptor any ChKRMBlock objects associated with this item.

virtual void	LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor) override
	Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. 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 (std::ostream &outstream, int level=0) const
	Writes the hierarchy of contained bodies, markers, etc. More...

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

virtual void	ArchiveIn (ChArchiveIn &archive_in) override
	Method to allow 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	AddVisualModel (std::shared_ptr< ChVisualModel > model)
	Add an (optional) visualization model. More...

std::shared_ptr< ChVisualModel >	GetVisualModel () const
	Access the visualization model (if any). More...

void	AddVisualShape (std::shared_ptr< ChVisualShape > shape, const ChFrame<> &frame=ChFrame<>())
	Add the specified visual shape to the visualization model. More...

std::shared_ptr< ChVisualShape >	GetVisualShape (unsigned int i) const
	Access the specified visualization shape in the visualization model (if any). More...

void	AddVisualShapeFEA (std::shared_ptr< ChVisualShapeFEA > shapeFEA)
	Add the specified FEA visualization object to the visualization model. More...

std::shared_ptr< ChVisualShapeFEA >	GetVisualShapeFEA (unsigned int i) const
	Access the specified FEA visualization object in the visualization model (if any). More...

virtual ChFrame	GetVisualModelFrame (unsigned int nclone=0) const
	Get the reference frame (expressed in and relative to the absolute frame) of the visual model. More...

virtual unsigned int	GetNumVisualModelClones () const
	Return the number of clones of the visual model associated with this physics item. More...

void	AddCamera (std::shared_ptr< ChCamera > camera)
	Attach a ChCamera to this physical item. More...

std::vector< std::shared_ptr< ChCamera > >	GetCameras () const
	Get the set of cameras attached to this physics item.

virtual bool	IsActive () const
	Return true if the object is active and included in dynamics.

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

virtual ChAABB	GetTotalAABB ()
	Get the entire AABB axis-aligned bounding box of the object. More...

virtual void	GetCenter (ChVector3d &mcenter)
	Get a symbolic 'center' of the object. More...

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
	Get the unique integer identifier of this object. More...

void	SetTag (int tag)
	Set an object integer tag (default: -1). More...

int	GetTag () const
	Get the tag of this object.

void	SetName (const std::string &myname)
	Set the name of this object.

const std::string &	GetName () const
	Get the name of this object.

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

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

virtual std::string &	ArchiveContainerName ()

Protected Member Functions
virtual void	SetupInitial () override

Protected Member Functions inherited from chrono::ChObj
int	GenerateUniqueIdentifier ()

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

std::vector< std::shared_ptr< ChShaft > >	shaftlist
	list of 1-D shafts

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

unsigned int	m_num_bodies_active
	number of active bodies

unsigned int	m_num_bodies_sleep
	number of sleeping bodies

unsigned int	m_num_bodies_fixed
	number of fixed bodies

unsigned int	m_num_shafts
	number of active shafts

unsigned int	m_num_shafts_sleep
	number of sleeping shafts

unsigned int	m_num_shafts_fixed
	number of fixed shafts

unsigned int	m_num_links_active
	number of active links

unsigned int	m_num_meshes
	number of meshes

unsigned int	m_num_otherphysicsitems_active
	number of other active physics items

unsigned int	m_num_coords_pos
	number of scalar position-level coordinates for all active bodies

unsigned int	m_num_coords_vel
	number of scalar velocity-level coordinates for all active bodies

unsigned int	m_num_constr
	number of scalar constraints

unsigned int	m_num_constr_bil
	number of scalar bilateral constraints

unsigned int	m_num_constr_uni
	number of scalar unilateral constraints

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

std::shared_ptr< ChVisualModelInstance >	vis_model_instance
	instantiated visualization model

std::vector< std::shared_ptr< ChCamera > >	cameras
	set of cameras

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
	object simulation time

std::string	m_name
	object name

int	m_identifier
	object unique identifier

int	m_tag
	user-supplied tag

Friends
class	ChSystem

class	ChSystemMulticore

ChApi void	swap (ChAssembly &first, ChAssembly &second)
	Swap the contents of the two provided ChAssembly objects. More...

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(), 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::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.

◆ 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().

◆ GetNumCoordsPosLevel()

virtual unsigned int chrono::ChAssembly::GetNumCoordsPosLevel ( )

inlineoverridevirtual

Get the number of scalar coordinates at the position level.

This count includes the 4th dimension of quaternions (if any), thus potentially differing from GetNumCoordsVelLevel().

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ IntLoadLumpedMass_Md()

void chrono::ChAssembly::IntLoadLumpedMass_Md	(	const unsigned int	off,
		ChVectorDynamic<> &	Md,
		double &	err,
		const double	c
	)

overridevirtual

Adds the lumped mass to a Md vector, representing a mass diagonal matrix.

Used by lumped explicit integrators. If mass lumping is impossible or approximate, adds scalar error to "error" parameter. Md += c*diag(M)

Parameters

off	offset in Md vector
Md	result: Md vector, diagonal of the lumped mass matrix
err	result: not touched if lumping does not introduce errors
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ IntStateGetIncrement()

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

overridevirtual

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

By default, when DOF = DOF_w, it does just the difference of two state vectors, 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, final position part
x	state vector, initial position part
off_v	offset in v state vector
Dv	state vector, increment. Here gets the result

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ IntStateScatter()

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

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
full_update	perform complete update

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ 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 copied into the q 'unknowns' term of the variables
R	vector copied into the F 'force' term of the variables
off_L	offset for L and Qc
L	vector copied into the L 'lagrangian ' term of the constraints
Qc	vector copied into the Qb 'constraint' term of the constraints

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::modal::ChModalAssembly.

◆ LoadKRMMatrices()

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

overridevirtual

Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects.

The resulting KRM blocks represent linear combinations of the K, R, and M matrices, with the specified coefficients Kfactor, Rfactor,and Mfactor, respectively. Note: signs are flipped from the term dF/dx in the integrator: K = -dF/dq and R = -dF/dv.

Reimplemented from chrono::ChPhysicsItem.

Reimplemented in chrono::modal::ChModalAssembly.

◆ 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::modal::ChModalAssembly.

◆ ShowHierarchy()

void chrono::ChAssembly::ShowHierarchy	(	std::ostream &	outstream,
		int	level = `0`
	)		const

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.

◆ 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 (Euler integration).

Reimplemented from chrono::ChPhysicsItem.

◆ 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.

◆ 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.

Friends And Related Function Documentation

◆ swap

ChApi void swap	(	ChAssembly &	first,
		ChAssembly &	second
	)

friend

Swap the contents of the two provided ChAssembly objects.

Implemented as a friend (as opposed to a member function) so classes with a ChAssembly member can use ADL when implementing their own swap.

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 Member Functions

Protected Attributes

Friends

Member Function Documentation

◆ Add()

◆ AddBatch()

◆ ConstraintsFetch_react()

◆ FlushBatch()

◆ GetNumCoordsPosLevel()

◆ IntFromDescriptor()

◆ IntLoadConstraint_C()

◆ IntLoadConstraint_Ct()

◆ IntLoadLumpedMass_Md()

◆ IntLoadResidual_CqL()

◆ IntLoadResidual_F()

◆ IntLoadResidual_Mv()

◆ IntStateGather()

◆ IntStateGatherAcceleration()

◆ IntStateGatherReactions()

◆ IntStateGetIncrement()

◆ IntStateIncrement()

◆ IntStateScatter()

◆ IntStateScatterAcceleration()

◆ IntStateScatterReactions()

◆ IntToDescriptor()

◆ LoadKRMMatrices()

◆ Setup()

◆ ShowHierarchy()

◆ VariablesFbIncrementMq()

◆ VariablesQbIncrementPosition()

◆ VariablesQbLoadSpeed()

◆ VariablesQbSetSpeed()

Friends And Related Function Documentation

◆ swap