Moby::TimeSteppingSimulator Class Reference

An event-driven simulator. More...

#include <TimeSteppingSimulator.h>

Inheritance diagram for Moby::TimeSteppingSimulator:

Public Member Functions
	TimeSteppingSimulator ()
	Default constructor.
virtual void	load_from_xml (boost::shared_ptr< const XMLTree > node, std::map< std::string, BasePtr > &id_map)
	Implements Base::load_from_xml()
virtual void	save_to_xml (XMLTreePtr node, std::list< boost::shared_ptr< const Base > > &shared_objects) const
	Implements Base::save_to_xml()
virtual double	step (double dt)
	Steps the simulator forward by the given step size.
boost::shared_ptr < ContactParameters >	get_contact_parameters (CollisionGeometryPtr geom1, CollisionGeometryPtr geom2) const
boost::shared_ptr < TimeSteppingSimulator >	get_this ()
	Gets the shared pointer for this.
Public Member Functions inherited from Moby::ConstraintSimulator
	ConstraintSimulator ()
	Default constructor.
boost::shared_ptr < ContactParameters >	get_contact_parameters (CollisionGeometryPtr geom1, CollisionGeometryPtr geom2) const
	Gets the contact data between a pair of geometries (if any) More...
const std::vector < PairwiseDistInfo > &	get_pairwise_distances () const
std::vector < UnilateralConstraint > &	get_compliant_constraints ()
	Gets the (sorted) compliant constraint data.
std::vector < UnilateralConstraint > &	get_rigid_constraints ()
	Gets the (sorted) rigid constraint data.
boost::shared_ptr < CollisionDetection >	get_collision_detection () const
	Gets the collision detection mechanism.
Public Member Functions inherited from Moby::Simulator
	Simulator ()
	Sets up the simulator. More...
ControlledBodyPtr	find_dynamic_body (const std::string &name) const
	Finds the dynamic body in the simulator, if any. More...
void	add_dynamic_body (ControlledBodyPtr body)
	Adds a dynamic body to the simulator. More...
void	remove_dynamic_body (ControlledBodyPtr body)
	Removes a dynamic body from the simulator.
void	update_visualization ()
	Updates all visualization under the simulator.
const std::vector < ControlledBodyPtr > &	get_dynamic_bodies () const
	Gets the list of dynamic bodies in the simulator. More...
void	add_transient_vdata (osg::Node *vdata)
	Adds transient visualization data to the simulator.
osg::Node *	get_persistent_vdata () const
	Gets the persistent visualization data.
osg::Node *	get_transient_vdata () const
	Gets the transient (one-step) visualization data.
template<class ForwardIterator >
double	integrate (double dt, ForwardIterator begin, ForwardIterator end)
	Integrates both position and velocity of rigid _bodies. More...
Public Member Functions inherited from Moby::Base
	Base (const Base *b)

Public Attributes
double	min_step_size
std::set< Ravelin::sorted_pair < CollisionGeometryPtr > >	unchecked_pairs
	Determines whether two geometries are not checked.
std::vector< std::pair < ControlledBodyPtr, Ravelin::VectorNd > >	_x0
	Vectors set and passed to collision detection.
std::vector< std::pair < ControlledBodyPtr, Ravelin::VectorNd > >	_x1
Public Attributes inherited from Moby::ConstraintSimulator
ConstraintStabilization	cstab
	The constraint stabilization mechanism.
std::set< Ravelin::sorted_pair < CollisionGeometryPtr > >	unchecked_pairs
	Determines whether two geometries are not checked.
std::vector< std::pair < ControlledBodyPtr, Ravelin::VectorNd > >	_x0
	Vectors set and passed to collision detection.
std::vector< std::pair < ControlledBodyPtr, Ravelin::VectorNd > >	_x1
boost::shared_ptr < ContactParameters >(*	get_contact_parameters_callback_fn )(CollisionGeometryPtr g1, CollisionGeometryPtr g2)
	Callback function for getting contact parameters.
void(*	post_mini_step_callback_fn )(ConstraintSimulator *s)
	Callback function after a mini-step is completed.
void(*	constraint_callback_fn )(std::vector< UnilateralConstraint > &, boost::shared_ptr< void >)
	The callback function (called when constraints have been determined) More...
void(*	constraint_post_callback_fn )(const std::vector< UnilateralConstraint > &, boost::shared_ptr< void >)
	The callback function (called after forces/impulses are applied)
boost::shared_ptr< void >	constraint_callback_data
	Data passed to unilateral constraint callback.
boost::shared_ptr< void >	constraint_post_callback_data
	Data passed to post-constraint callback.
std::map< Ravelin::sorted_pair < BasePtr >, boost::shared_ptr < ContactParameters > >	contact_params
	Mapping from objects to contact parameters.
bool	render_contact_points
	If set to 'true' simulator will process contact points for rendering.
Public Attributes inherited from Moby::Simulator
double	current_time
	The current simulation time.
boost::shared_ptr< Dissipation >	dissipator
	The dissipation mechanism for larger time steps.
void(*	post_step_callback_fn )(Simulator *s)
	Callback function after a step is completed.
double	dynamics_time
	User time spent by dynamics on the last step.
std::vector< JointPtr >	implicit_joints
	Set of implicit joints maintained in the simulation (does not include implicit joints belonging to RCArticulatedBody objects)
Public Attributes inherited from Moby::Base
boost::shared_ptr< void >	userdata
	Any relevant userdata.
std::string	id
	The unique ID for this object.

Protected Member Functions
bool	constraints_met (const std::vector< PairwiseDistInfo > &current_pairwise_distances)
	Checks to see whether all constraints are met.
std::set< Ravelin::sorted_pair < CollisionGeometryPtr > >	get_current_contact_geoms () const
	Gets the current set of contact geometries.
double	do_mini_step (double dt)
	Does a full integration cycle (but not necessarily a full step)
void	step_si_Euler (double dt)
	Does a semi-implicit step. More...
double	calc_next_CA_Euler_step () const
	Finds the next event time assuming constant velocity. More...
Protected Member Functions inherited from Moby::ConstraintSimulator
void	calc_impacting_unilateral_constraint_forces (double dt)
	Handles constraints.
void	find_unilateral_constraints ()
	Finds the set of unilateral constraints.
void	calc_compliant_unilateral_constraint_forces ()
	Computes compliant contact forces.
void	preprocess_constraint (UnilateralConstraint &e)
	Performs necessary preprocessing on an constraint.
void	determine_geometries ()
	Sets up the list of collision geometries.
void	broad_phase (double dt)
	Does broad phase collision detection, identifying which pairs of geometries may come into contact over time step of dt.
void	calc_pairwise_distances ()
	Computes pairwise distances of geometries at their current poses, using broad phase results to determine which pairs should be checked. More...
void	visualize_contact (UnilateralConstraint &constraint)
	Draws a ray directed from a contact point along the contact normal.
double	calc_CA_step ()
double	calc_next_CA_Euler_step (double contact_dist_thresh) const
Protected Member Functions inherited from Moby::Simulator
void	apply_impulse (boost::shared_ptr< Ravelin::DynamicBodyd > db, const Ravelin::SharedVectorNd &gj)
	Applies a generalized impulse to a dynamic body. More...
void	solve (const std::vector< boost::shared_ptr< Ravelin::DynamicBodyd > > &island, const std::vector< JointPtr > &island_joints, const Ravelin::VectorNd &v, const Ravelin::VectorNd &f, double dt, Ravelin::VectorNd &a, Ravelin::VectorNd &lambda) const
virtual double	check_pairwise_constraint_violations (double t)
void	find_islands (std::vector< std::vector< boost::shared_ptr< Ravelin::DynamicBodyd > > > &islands)
	Finds islands.
unsigned	num_generalized_coordinates (const std::vector< boost::shared_ptr< Ravelin::DynamicBodyd > > &island) const
	Gets the number of generalized coordinates in an island.
void	calc_fwd_dyn (double dt)
	Calculates forward dynamics for bodies (does not consider unilateral constraints)
void	precalc_fwd_dyn ()
	Prepares to calculate forward dynamics for bodies.
template<class ForwardIterator >
double	integrate (double step_size, ForwardIterator begin, ForwardIterator end)
	Integrates both position and velocity of rigid _bodies. More...
double	integrate (double step_size)
	Integrates all dynamic bodies.

Friends
class	CollisionDetection

Additional Inherited Members
Static Public Member Functions inherited from Moby::Base
template<class T >
static boost::shared_ptr< T >	clone (boost::shared_ptr< T > x)
	Static method for cloning a shared pointer.
Protected Attributes inherited from Moby::ConstraintSimulator
ImpactConstraintHandler	_impact_constraint_handler
	Object for handling impact constraints.
PenaltyConstraintHandler	_penalty_constraint_handler
	Object for handling penalty constraints.
std::vector< UnilateralConstraint >	_rigid_constraints
	The vector of rigid constraints.
std::vector< UnilateralConstraint >	_compliant_constraints
	The vector of compliant constraints.
std::vector< PairwiseDistInfo >	_pairwise_distances
	Pairwise distances at bodies' current configurations.
Ravelin::VectorNd	_workV
	Work vector.
boost::shared_ptr < CollisionDetection >	_coldet
	The collision detection mechanism.
std::vector< CollisionGeometryPtr >	_geometries
	The geometries in the simulator.
std::vector< std::pair < CollisionGeometryPtr, CollisionGeometryPtr > >	_pairs_to_check
	Geometric pairs that should be checked for unilateral constraints (according to broad phase collision detection)
Protected Attributes inherited from Moby::Simulator
osg::Group *	_persistent_vdata
osg::Group *	_transient_vdata
std::vector< ControlledBodyPtr >	_bodies
	The set of bodies in the simulation.
Ravelin::VectorNd	_current_dx
	The derivative at the current time.

Detailed Description

An event-driven simulator.

Member Function Documentation

double TimeSteppingSimulator::calc_next_CA_Euler_step ( ) const

protected

Finds the next event time assuming constant velocity.

This method returns the next possible time of contact, discarding current contacts from consideration.

Note

proper operation of this function is critical. If the function improperly designates an event as not occuring at the current time, calc_next_CA_Euler_step(.) will return a small value and prevent large integration steps from being taken. If the function improperly designates an event as occuring at the current time, constraint violation could occur.

void TimeSteppingSimulator::step_si_Euler ( double  dt )

protected

Does a semi-implicit step.

Does a semi-implicit step (version with conservative advancement)

---

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

• /home/drum/Moby/include/Moby/TimeSteppingSimulator.h
• /home/drum/Moby/src/TimeSteppingSimulator.cpp