Lazy Probabilistic RoadMap planner. More...

#include <ompl/geometric/planners/prm/LazyPRM.h>

Inheritance diagram for ompl::geometric::LazyPRM:

Classes
struct	edge_flags_t

struct	vertex_component_t

struct	vertex_flags_t

struct	vertex_state_t

Public Types
using	Vertex = boost::adjacency_list_traits< boost::vecS, boost::listS, boost::undirectedS >::vertex_descriptor
	The type for a vertex in the roadmap.

using	Graph = boost::adjacency_list< boost::vecS, boost::listS, boost::undirectedS, boost::property< vertex_state_t, base::State *, boost::property< boost::vertex_index_t, unsigned long int, boost::property< vertex_flags_t, unsigned int, boost::property< vertex_component_t, unsigned long int, boost::property< boost::vertex_predecessor_t, Vertex, boost::property< boost::vertex_rank_t, unsigned long int > >> >> >, boost::property< boost::edge_weight_t, base::Cost, boost::property< edge_flags_t, unsigned int > >>
	The underlying roadmap graph. More...

using	Edge = boost::graph_traits< Graph >::edge_descriptor
	The type for an edge in the roadmap.

using	RoadmapNeighbors = std::shared_ptr< NearestNeighbors< Vertex > >
	A nearest neighbors data structure for roadmap vertices.

using	ConnectionStrategy = std::function< const std::vector< Vertex > &(const Vertex)>
	A function returning the milestones that should be attempted to connect to.

using	ConnectionFilter = std::function< bool(const Vertex &, const Vertex &)>
	A function that can reject connections. More...

Public Types inherited from ompl::base::Planner
using	PlannerProgressProperty = std::function< std::string()>
	Definition of a function which returns a property about the planner's progress that can be queried by a benchmarking routine.

using	PlannerProgressProperties = std::map< std::string, PlannerProgressProperty >
	A dictionary which maps the name of a progress property to the function to be used for querying that property.

Public Member Functions
	LazyPRM (const base::SpaceInformationPtr &si, bool starStrategy=false)
	Constructor.

	LazyPRM (const base::PlannerData &data, bool starStrategy=false)
	Constructor.

void	setRange (double distance)
	Set the maximum length of a motion to be added to the roadmap.

double	getRange () const
	Get the range the planner is using.

template<template< typename T > class NN>
void	setNearestNeighbors ()
	Set a different nearest neighbors datastructure.

void	setProblemDefinition (const base::ProblemDefinitionPtr &pdef) override

void	setConnectionStrategy (const ConnectionStrategy &connectionStrategy)
	Set the connection strategy function that specifies the milestones that connection attempts will be make to for a given milestone. More...

void	setDefaultConnectionStrategy ()

void	setMaxNearestNeighbors (unsigned int k)
	Convenience function that sets the connection strategy to the default one with k nearest neighbors.

void	setConnectionFilter (const ConnectionFilter &connectionFilter)
	Set the function that can reject a milestone connection. More...

unsigned long int	milestoneCount () const
	Return the number of milestones currently in the graph.

unsigned long int	edgeCount () const
	Return the number of edges currently in the graph.

void	getPlannerData (base::PlannerData &data) const override
	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).

void	setup () override
	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.

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

void	clearQuery () override
	Clear the query previously loaded from the ProblemDefinition. Subsequent calls to solve() will reuse the previously computed roadmap, but will clear the set of input states constructed by the previous call to solve(). This enables multi-query functionality for LazyPRM.

void	clearValidity ()
	change the validity flag of each node and edge to VALIDITY_UNKNOWN

base::PlannerStatus	solve (const base::PlannerTerminationCondition &ptc) override
	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 for 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). If clearQuery() is called, the planner may retain prior datastructures generated from a previous query on a new problem definition. The function terminates if the call to ptc returns true.

Public Member Functions inherited from ompl::base::Planner
	Planner (const Planner &)=delete

Planner &	operator= (const Planner &)=delete

	Planner (SpaceInformationPtr si, std::string name)
	Constructor.

virtual	~Planner ()=default
	Destructor.

template<class T >
T *	as ()
	Cast this instance to a desired type. More...

template<class T >
const T *	as () const
	Cast this instance to a desired type. More...

const SpaceInformationPtr &	getSpaceInformation () const
	Get the space information this planner is using.

const ProblemDefinitionPtr &	getProblemDefinition () const
	Get the problem definition the planner is trying to solve.

ProblemDefinitionPtr &	getProblemDefinition ()
	Get the problem definition the planner is trying to solve.

const PlannerInputStates &	getPlannerInputStates () const
	Get the planner input states.

virtual void	setProblemDefinition (const ProblemDefinitionPtr &pdef)
	Set the problem definition for the planner. The problem needs to be set before calling solve(). Note: If this problem definition replaces a previous one, it may also be necessary to call clear() or clearQuery().

PlannerStatus	solve (const PlannerTerminationConditionFn &ptc, double checkInterval)
	Same as above except the termination condition is only evaluated at a specified interval.

PlannerStatus	solve (double solveTime)
	Same as above except the termination condition is solely a time limit: the number of seconds the algorithm is allowed to spend planning.

const std::string &	getName () const
	Get the name of the planner.

void	setName (const std::string &name)
	Set the name of the planner.

const PlannerSpecs &	getSpecs () const
	Return the specifications (capabilities of this planner)

virtual void	checkValidity ()
	Check to see if the planner is in a working state (setup has been called, a goal was set, the input states seem to be in order). In case of error, this function throws an exception.

bool	isSetup () const
	Check if setup() was called for this planner.

ParamSet &	params ()
	Get the parameters for this planner.

const ParamSet &	params () const
	Get the parameters for this planner.

const PlannerProgressProperties &	getPlannerProgressProperties () const
	Retrieve a planner's planner progress property map.

virtual void	printProperties (std::ostream &out) const
	Print properties of the motion planner.

virtual void	printSettings (std::ostream &out) const
	Print information about the motion planner's settings.

Protected Member Functions
std::string	getIterationCount () const

std::string	getBestCost () const

std::string	getMilestoneCountString () const

std::string	getEdgeCountString () const

void	freeMemory ()
	Free all the memory allocated by the planner.

Vertex	addMilestone (base::State *state)
	Construct a milestone for a given state (state), store it in the nearest neighbors data structure and then connect it to the roadmap in accordance to the connection strategy.

void	uniteComponents (Vertex a, Vertex b)

void	markComponent (Vertex v, unsigned long int newComponent)

long int	solutionComponent (std::pair< std::size_t, std::size_t > *startGoalPair) const
	Check if any pair of a start state and goal state are part of the same connected component. If so, return the id of that component. Otherwise, return -1.

ompl::base::PathPtr	constructSolution (const Vertex &start, const Vertex &goal)
	Given two milestones from the same connected component, construct a path connecting them and set it as the solution.

double	distanceFunction (const Vertex a, const Vertex b) const
	Compute distance between two milestones (this is simply distance between the states of the milestones)

base::Cost	costHeuristic (Vertex u, Vertex v) const
	Given two vertices, returns a heuristic on the cost of the path connecting them. This method wraps OptimizationObjective::motionCostHeuristic.

Protected Member Functions inherited from ompl::base::Planner
template<typename T , typename PlannerType , typename SetterType , typename GetterType >
void	declareParam (const std::string &name, const PlannerType &planner, const SetterType &setter, const GetterType &getter, const std::string &rangeSuggestion="")
	This function declares a parameter for this planner instance, and specifies the setter and getter functions.

template<typename T , typename PlannerType , typename SetterType >
void	declareParam (const std::string &name, const PlannerType &planner, const SetterType &setter, const std::string &rangeSuggestion="")
	This function declares a parameter for this planner instance, and specifies the setter function.

void	addPlannerProgressProperty (const std::string &progressPropertyName, const PlannerProgressProperty &prop)
	Add a planner progress property called progressPropertyName with a property querying function prop to this planner's progress property map.

Protected Attributes
bool	starStrategy_
	Flag indicating whether the default connection strategy is the Star strategy.

ConnectionStrategy	connectionStrategy_
	Function that returns the milestones to attempt connections with.

ConnectionFilter	connectionFilter_
	Function that can reject a milestone connection.

bool	userSetConnectionStrategy_ {false}
	Flag indicating whether the employed connection strategy was set by the user (or defaults are assumed)

double	maxDistance_ {0.}
	The maximum length of a motion to be added to a tree.

base::StateSamplerPtr	sampler_
	Sampler user for generating random in the state space.

RoadmapNeighbors	nn_
	Nearest neighbors data structure.

Graph	g_
	Connectivity graph.

std::vector< Vertex >	startM_
	Array of start milestones.

std::vector< Vertex >	goalM_
	Array of goal milestones.

boost::property_map< Graph, boost::vertex_index_t >::type	indexProperty_
	Access to the internal base::state at each Vertex.

boost::property_map< Graph, vertex_state_t >::type	stateProperty_
	Access to the internal base::state at each Vertex.

boost::property_map< Graph, boost::edge_weight_t >::type	weightProperty_
	Access to the weights of each Edge.

boost::property_map< Graph, vertex_component_t >::type	vertexComponentProperty_
	Access the connected component of a vertex.

boost::property_map< Graph, vertex_flags_t >::type	vertexValidityProperty_
	Access the validity state of a vertex.

boost::property_map< Graph, edge_flags_t >::type	edgeValidityProperty_
	Access the validity state of an edge.

unsigned long int	componentCount_ {0}
	Number of connected components created so far. This is used as an ID only, does not represent the actual number of components currently in the graph.

std::map< unsigned long int, unsigned long int >	componentSize_
	The number of elements in each component in the LazyPRM roadmap.

base::OptimizationObjectivePtr	opt_
	Objective cost function for PRM graph edges.

base::Cost	bestCost_ {std::numeric_limits<double>::quiet_NaN()}

unsigned long int	iterations_ {0}

Protected Attributes inherited from ompl::base::Planner
SpaceInformationPtr	si_
	The space information for which planning is done.

ProblemDefinitionPtr	pdef_
	The user set problem definition.

PlannerInputStates	pis_
	Utility class to extract valid input states

std::string	name_
	The name of this planner.

PlannerSpecs	specs_
	The specifications of the planner (its capabilities)

ParamSet	params_
	A map from parameter names to parameter instances for this planner. This field is populated by the declareParam() function.

PlannerProgressProperties	plannerProgressProperties_
	A mapping between this planner's progress property names and the functions used for querying those progress properties.

bool	setup_
	Flag indicating whether setup() has been called.

Static Protected Attributes
static const unsigned int	VALIDITY_UNKNOWN = 0
	Flag indicating validity of an edge of a vertex.

static const unsigned int	VALIDITY_TRUE = 1
	Flag indicating validity of an edge of a vertex.

Detailed Description

Lazy Probabilistic RoadMap planner.

Short description: LazyPRM is a planner that constructs a roadmap of milestones that approximate the connectivity of the state space, just like PRM does. The difference is that the planner uses lazy collision checking.

External documentation: R. Bohlin and L.E. Kavraki Path Planning Using Lazy PRM IEEE International Conference on Robotics and Automation, San Francisco, pp. 521–528, 2000. DOI: 10.1109/ROBOT.2000.844107
[more]

Definition at line 105 of file LazyPRM.h.

Member Typedef Documentation

◆ ConnectionFilter

using ompl::geometric::LazyPRM::ConnectionFilter = std::function<bool (const Vertex &, const Vertex &)>

A function that can reject connections.

This is called after previous connections from the neighbor list have been added to the roadmap.

Definition at line 176 of file LazyPRM.h.

◆ Graph

using ompl::geometric::LazyPRM::Graph = boost::adjacency_list< boost::vecS, boost::listS, boost::undirectedS, boost::property< vertex_state_t, base::State *, boost::property< boost::vertex_index_t, unsigned long int, boost::property<vertex_flags_t, unsigned int, boost::property<vertex_component_t, unsigned long int, boost::property<boost::vertex_predecessor_t, Vertex, boost::property<boost::vertex_rank_t, unsigned long int> >> >> >, boost::property<boost::edge_weight_t, base::Cost, boost::property<edge_flags_t, unsigned int> >>

The underlying roadmap graph.

Any BGL graph representation could be used here. Because we: expect the roadmap to be sparse (m<n^2), an adjacency_list is more appropriate than an adjacency_matrix. We use listS for the vertex list because vertex descriptors are invalidated by remove operations if using vecS.

Obviously, a ompl::base::State* vertex property is required.: The incremental connected components algorithm requires vertex_predecessor_t and vertex_rank_t properties. If boost::vecS is not used for vertex storage, then there must also be a boost:vertex_index_t property manually added.

Edges should be undirected and have a weight property.

Definition at line 159 of file LazyPRM.h.

Member Function Documentation

◆ setConnectionFilter()

void ompl::geometric::LazyPRM::setConnectionFilter ( const ConnectionFilter & connectionFilter )

inline

Set the function that can reject a milestone connection.

The given function is called immediately before a connection: is checked for collision and added to the roadmap. Other neighbors may have already been connected before this function is called. This allows certain heuristics that use the structure of the roadmap (like connected components or useful cycles) to be implemented by changing this function.

Parameters

connectionFilter A function that takes the new milestone, a neighboring milestone and returns whether a connection should be attempted.

Definition at line 250 of file LazyPRM.h.

◆ setConnectionStrategy()

void ompl::geometric::LazyPRM::setConnectionStrategy ( const ConnectionStrategy & connectionStrategy )

inline

Set the connection strategy function that specifies the milestones that connection attempts will be make to for a given milestone.

The behavior and performance of PRM can be changed drastically: by varying the number and properties if the milestones that are connected to each other.

Parameters

pdef	A function that takes a milestone as an argument and returns a collection of other milestones to which a connection attempt must be made. The default connection strategy is to connect a milestone's 10 closest neighbors.

Definition at line 224 of file LazyPRM.h.

◆ setDefaultConnectionStrategy()

void ompl::geometric::LazyPRM::setDefaultConnectionStrategy ( )

Set default strategy for connecting to nearest neighbors

Definition at line 230 of file LazyPRM.cpp.

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

ompl/geometric/planners/prm/LazyPRM.h
ompl/geometric/planners/prm/src/LazyPRM.cpp

Classes

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Public Member Functions

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