ompl::geometric::EST Class Reference

Expansive Space Trees. More...

#include <EST.h>

Inheritance diagram for ompl::geometric::EST:

Classes
class	Motion
	The definition of a motion. More...
struct	TreeData
	The data contained by a tree of exploration. More...
Public Member Functions
virtual void	clear (void)
	Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() will ignore all previous work.
	EST (const base::SpaceInformationPtr &si)
	Constructor.
double	getGoalBias (void) const
	Get the goal bias the planner is using.
virtual void	getPlannerData (base::PlannerData &data) const
	Get information about the current run of the motion planner. Repeated calls to this function will update data (only additions are made). This is useful to see what changed in the exploration datastructure, between calls to solve(), for example (without calling clear() in between).
const base::ProjectionEvaluatorPtr &	getProjectionEvaluator (void) const
	Get the projection evaluator.
double	getRange (void) const
	Get the range the planner is using.
void	setGoalBias (double goalBias)
	In the process of randomly selecting states in the state space to attempt to go towards, the algorithm may in fact choose the actual goal state, if it knows it, with some probability. This probability is a real number between 0.0 and 1.0; its value should usually be around 0.05 and should not be too large. It is probably a good idea to use the default value.
void	setProjectionEvaluator (const std::string &name)
	Set the projection evaluator (select one from the ones registered with the state space).
void	setProjectionEvaluator (const base::ProjectionEvaluatorPtr &projectionEvaluator)
	Set the projection evaluator. This class is able to compute the projection of a given state.
void	setRange (double distance)
	Set the range the planner is supposed to use.
virtual void	setup (void)
	Perform extra configuration steps, if needed. This call will also issue a call to ompl::base::SpaceInformation::setup() if needed. This must be called before solving.
virtual bool	solve (const base::PlannerTerminationCondition &ptc)
	Function that can solve the motion planning problem. This function can be called multiple times on the same problem, without calling clear() in between. This allows the planner to continue work more time on an unsolved problem, for example. If this option is used, it is assumed the problem definition is not changed (unpredictable results otherwise). The only change in the problem definition that is accounted for is the addition of starting or goal states (but not changing previously added start/goal states). The function terminates if the call to ptc returns true.
virtual	~EST (void)
Protected Types
typedef std::vector< Motion * >	MotionSet
	An array of motions.
Protected Member Functions
void	addMotion (Motion *motion)
	Add a motion to the exploration tree.
void	freeMemory (void)
	Free the memory allocated by this planner.
Motion *	selectMotion (void)
	Select a motion to continue the expansion of the tree from.
Protected Attributes
double	goalBias_
	The fraction of time the goal is picked as the state to expand towards (if such a state is available).
double	maxDistance_
	The maximum length of a motion to be added to a tree.
base::ProjectionEvaluatorPtr	projectionEvaluator_
	This algorithm uses a discretization (a grid) to guide the exploration. The exploration is imposed on a projection of the state space.
RNG	rng_
	The random number generator.
base::ValidStateSamplerPtr	sampler_
	Valid state sampler.
TreeData	tree_
	The exploration tree constructed by this algorithm.

Detailed Description

Expansive Space Trees.

Short description: EST is a tree-based motion planner that attempts to detect the less explored area of the space through the use of a grid imposed on a projection of the state space. Using this information, EST continues tree expansion primarily from less explored areas. It is important to set the projection the algorithm uses (setProjectionEvaluator() function). If no projection is set, the planner will attempt to use the default projection associated to the state space. An exception is thrown if no default projection is available either.

External documentation: D. Hsu, J.-C. Latombe, and R. Motwani, Path planning in expansive configuration spaces, Intl. J. Computational Geometry and Applications, vol. 9, no. 4-5, pp. 495–512, 1999. DOI: 10.1142/S0218195999000285
[PDF]

Definition at line 68 of file EST.h.

Member Typedef Documentation

typedef std::vector<Motion*> ompl::geometric::EST::MotionSet [protected]

An array of motions.

Definition at line 149 of file EST.h.

Constructor & Destructor Documentation

ompl::geometric::EST::EST ( const base::SpaceInformationPtr & si ) [inline]

Constructor.

Definition at line 46 of file EST.h.

virtual ompl::geometric::EST::~EST ( void ) [inline, virtual]

Definition at line 54 of file EST.h.

Member Function Documentation

void ompl::geometric::EST::addMotion ( Motion * motion ) [protected]

Add a motion to the exploration tree.

virtual void ompl::geometric::EST::clear ( void ) [virtual]

Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() will ignore all previous work.

Reimplemented from ompl::base::Planner.

void ompl::geometric::EST::freeMemory ( void ) [protected]

Free the memory allocated by this planner.

double ompl::geometric::EST::getGoalBias ( void ) const [inline]

Get the goal bias the planner is using.

Definition at line 76 of file EST.h.

virtual void ompl::geometric::EST::getPlannerData ( base::PlannerData & data ) const [virtual]

Get information about the current run of the motion planner. Repeated calls to this function will update data (only additions are made). This is useful to see what changed in the exploration datastructure, between calls to solve(), for example (without calling clear() in between).

Reimplemented from ompl::base::Planner.

const base::ProjectionEvaluatorPtr& ompl::geometric::EST::getProjectionEvaluator ( void ) const [inline]

Get the projection evaluator.

Definition at line 112 of file EST.h.

double ompl::geometric::EST::getRange ( void ) const [inline]

Get the range the planner is using.

Definition at line 92 of file EST.h.

Motion* ompl::geometric::EST::selectMotion ( void ) [protected]

Select a motion to continue the expansion of the tree from.

void ompl::geometric::EST::setGoalBias ( double goalBias ) [inline]

In the process of randomly selecting states in the state space to attempt to go towards, the algorithm may in fact choose the actual goal state, if it knows it, with some probability. This probability is a real number between 0.0 and 1.0; its value should usually be around 0.05 and should not be too large. It is probably a good idea to use the default value.

Definition at line 70 of file EST.h.

void ompl::geometric::EST::setProjectionEvaluator ( const std::string & name ) [inline]

Set the projection evaluator (select one from the ones registered with the state space).

Definition at line 106 of file EST.h.

void ompl::geometric::EST::setProjectionEvaluator ( const base::ProjectionEvaluatorPtr & projectionEvaluator ) [inline]

Set the projection evaluator. This class is able to compute the projection of a given state.

Definition at line 99 of file EST.h.

void ompl::geometric::EST::setRange ( double distance ) [inline]

Set the range the planner is supposed to use.

This parameter greatly influences the runtime of the algorithm. It represents the maximum length of a motion to be added in the tree of motions.

Definition at line 86 of file EST.h.

virtual void ompl::geometric::EST::setup ( void ) [virtual]

Perform extra configuration steps, if needed. This call will also issue a call to ompl::base::SpaceInformation::setup() if needed. This must be called before solving.

Reimplemented from ompl::base::Planner.

virtual bool ompl::geometric::EST::solve ( const base::PlannerTerminationCondition & ptc ) [virtual]

Function that can solve the motion planning problem. This function can be called multiple times on the same problem, without calling clear() in between. This allows the planner to continue work more time on an unsolved problem, for example. If this option is used, it is assumed the problem definition is not changed (unpredictable results otherwise). The only change in the problem definition that is accounted for is the addition of starting or goal states (but not changing previously added start/goal states). The function terminates if the call to ptc returns true.

Implements ompl::base::Planner.