ompl::geometric::LBKPIECE1 Class Reference

Lazy Bi-directional KPIECE with one level of discretization. More...

#include <LBKPIECE1.h>

Inheritance diagram for ompl::geometric::LBKPIECE1:

Classes
class	Motion
	Representation of a motion for this algorithm. 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.
double	getBorderFraction (void) const
	Get the fraction of time to focus exploration on boundary.
double	getMinValidPathFraction (void) const
	Get the value of the fraction set by setMinValidPathFraction().
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.
	LBKPIECE1 (const base::SpaceInformationPtr &si)
	Constructor.
void	setBorderFraction (double bp)
	Set the fraction of time for focusing on the border (between 0 and 1). This is the minimum fraction used to select cells that are exterior (minimum because if 95% of cells are on the border, they will be selected with 95% chance, even if this fraction is set to 90%).
void	setMinValidPathFraction (double fraction)
	When extending a motion, the planner can decide to keep the first valid part of it, even if invalid states are found, as long as the valid part represents a sufficiently large fraction from the original motion. This function sets the minimum acceptable fraction.
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	~LBKPIECE1 (void)
Protected Member Functions
void	freeMotion (Motion *motion)
	Free the memory for a motion.
bool	isPathValid (Discretization< Motion > &disc, Motion motion, base::State temp)
	Since solutions are computed in a lazy fashion, once trees are connected, the solution found needs to be checked for validity. This function checks whether the reverse path from a given motion to a root is valid. If this is not the case, invalid motions are removed.
void	removeMotion (Discretization< Motion > &disc, Motion *motion)
	Remove a motion from a tree of motions.
Protected Attributes
Discretization< Motion >	dGoal_
	The goal tree.
Discretization< Motion >	dStart_
	The start tree.
double	maxDistance_
	The maximum length of a motion to be added to a tree.
double	minValidPathFraction_
	When extending a motion, the planner can decide to keep the first valid part of it, even if invalid states are found, as long as the valid part represents a sufficiently large fraction from the original motion.
base::ProjectionEvaluatorPtr	projectionEvaluator_
	The employed projection evaluator.
RNG	rng_
	The random number generator.
base::StateSamplerPtr	sampler_
	The employed state sampler.

Detailed Description

Lazy Bi-directional KPIECE with one level of discretization.

Short description: KPIECE is a tree-based planner that uses a discretization (multiple levels, in general) to guide the exploration of the continuous space. This implementation is a simplified one, using a single level of discretization: one grid. The grid is imposed on a projection of the state space. When exploring the space, preference is given to the boundary of this grid. The boundary is computed to be the set of grid cells that have less than 2n non-diagonal neighbors in an n-dimensional projection space. 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. This variant of the implementation use two trees of exploration with lazy collision checking, hence the LB prefix.

External documentation

I.A. Şucan and L.E. Kavraki, Kinodynamic motion planning by interior-exterior cell exploration, in Workshop on the Algorithmic Foundations of Robotics, Dec. 2008.
[PDF]
R. Bohlin and L.E. Kavraki, Path planning using lazy PRM, in Proc. 2000 IEEE Intl. Conf. on Robotics and Automation, pp. 521–528, 2000. DOI: 10.1109/ROBOT.2000.844107
[PDF]

Definition at line 81 of file LBKPIECE1.h.

Constructor & Destructor Documentation

ompl::geometric::LBKPIECE1::LBKPIECE1 ( const base::SpaceInformationPtr & si ) [inline]

Constructor.

Definition at line 86 of file LBKPIECE1.h.

virtual ompl::geometric::LBKPIECE1::~LBKPIECE1 ( void ) [inline, virtual]

Definition at line 96 of file LBKPIECE1.h.

Member Function Documentation

virtual void ompl::geometric::LBKPIECE1::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::LBKPIECE1::freeMotion ( Motion * motion ) [protected]

Free the memory for a motion.

double ompl::geometric::LBKPIECE1::getBorderFraction ( void ) const [inline]

Get the fraction of time to focus exploration on boundary.

Definition at line 149 of file LBKPIECE1.h.

double ompl::geometric::LBKPIECE1::getMinValidPathFraction ( void ) const [inline]

Get the value of the fraction set by setMinValidPathFraction().

Definition at line 166 of file LBKPIECE1.h.

virtual void ompl::geometric::LBKPIECE1::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::LBKPIECE1::getProjectionEvaluator ( void ) const [inline]

Get the projection evaluator.

Definition at line 115 of file LBKPIECE1.h.

double ompl::geometric::LBKPIECE1::getRange ( void ) const [inline]

Get the range the planner is using.

Definition at line 131 of file LBKPIECE1.h.

bool ompl::geometric::LBKPIECE1::isPathValid	(	Discretization< Motion > &	disc,
		Motion *	motion,
		base::State *	temp
	)			`[protected]`

Since solutions are computed in a lazy fashion, once trees are connected, the solution found needs to be checked for validity. This function checks whether the reverse path from a given motion to a root is valid. If this is not the case, invalid motions are removed.

void ompl::geometric::LBKPIECE1::removeMotion	(	Discretization< Motion > &	disc,
		Motion *	motion
	)			`[protected]`

Remove a motion from a tree of motions.

void ompl::geometric::LBKPIECE1::setBorderFraction ( double bp ) [inline]

Set the fraction of time for focusing on the border (between 0 and 1). This is the minimum fraction used to select cells that are exterior (minimum because if 95% of cells are on the border, they will be selected with 95% chance, even if this fraction is set to 90%).

Definition at line 141 of file LBKPIECE1.h.

void ompl::geometric::LBKPIECE1::setMinValidPathFraction ( double fraction ) [inline]

When extending a motion, the planner can decide to keep the first valid part of it, even if invalid states are found, as long as the valid part represents a sufficiently large fraction from the original motion. This function sets the minimum acceptable fraction.

Definition at line 160 of file LBKPIECE1.h.

void ompl::geometric::LBKPIECE1::setProjectionEvaluator ( const std::string & name ) [inline]

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

Definition at line 109 of file LBKPIECE1.h.

void ompl::geometric::LBKPIECE1::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 102 of file LBKPIECE1.h.

void ompl::geometric::LBKPIECE1::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 125 of file LBKPIECE1.h.

virtual void ompl::geometric::LBKPIECE1::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::LBKPIECE1::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.

Member Data Documentation

Discretization<Motion> ompl::geometric::LBKPIECE1::dGoal_ [protected]

The goal tree.

Definition at line 237 of file LBKPIECE1.h.

Discretization<Motion> ompl::geometric::LBKPIECE1::dStart_ [protected]

The start tree.

Definition at line 234 of file LBKPIECE1.h.

double ompl::geometric::LBKPIECE1::maxDistance_ [protected]

The maximum length of a motion to be added to a tree.

Definition at line 247 of file LBKPIECE1.h.

double ompl::geometric::LBKPIECE1::minValidPathFraction_ [protected]

When extending a motion, the planner can decide to keep the first valid part of it, even if invalid states are found, as long as the valid part represents a sufficiently large fraction from the original motion.

Definition at line 244 of file LBKPIECE1.h.

base::ProjectionEvaluatorPtr ompl::geometric::LBKPIECE1::projectionEvaluator_ [protected]

The employed projection evaluator.

Definition at line 231 of file LBKPIECE1.h.

RNG ompl::geometric::LBKPIECE1::rng_ [protected]

The random number generator.

Definition at line 250 of file LBKPIECE1.h.

base::StateSamplerPtr ompl::geometric::LBKPIECE1::sampler_ [protected]

The employed state sampler.

Definition at line 228 of file LBKPIECE1.h.

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