ompl::geometric::SPARStwo Class Reference

SPArse Roadmap Spanner Version 2.0 More...

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

Inheritance diagram for ompl::geometric::SPARStwo:

Classes
struct	InterfaceData
	Interface information storage class, which does bookkeeping for criterion four. More...
struct	vertex_color_t
struct	vertex_interface_data_t
struct	vertex_state_t

Public Types
enum	GuardType {   START, GOAL, COVERAGE, CONNECTIVITY,   INTERFACE, QUALITY }
	Enumeration which specifies the reason a guard is added to the spanner.
using	VertexIndexType = unsigned long
	The type used internally for representing vertex IDs.
using	VertexPair = std::pair< VertexIndexType, VertexIndexType >
	Pair of vertices which support an interface.
using	InterfaceHash = std::unordered_map< VertexPair, InterfaceData >
	the hash which maps pairs of neighbor points to pairs of states
using	Graph = boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS, boost::property< vertex_state_t, base::State *, boost::property< boost::vertex_predecessor_t, VertexIndexType, boost::property< boost::vertex_rank_t, VertexIndexType, boost::property< vertex_color_t, GuardType, boost::property< vertex_interface_data_t, InterfaceHash > >> >>, boost::property< boost::edge_weight_t, base::Cost > >
	The underlying roadmap graph. More...
using	Vertex = boost::graph_traits< Graph >::vertex_descriptor
	Vertex in Graph.
using	Edge = boost::graph_traits< Graph >::edge_descriptor
	Edge in Graph.
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
	SPARStwo (const base::SpaceInformationPtr &si)
	Constructor.
	~SPARStwo () override
	Destructor.
void	setProblemDefinition (const base::ProblemDefinitionPtr &pdef) override
void	setStretchFactor (double t)
	Sets the stretch factor.
void	setSparseDeltaFraction (double D)
	Sets vertex visibility range as a fraction of max. extent.
void	setDenseDeltaFraction (double d)
	Sets interface support tolerance as a fraction of max. extent.
void	setMaxFailures (unsigned int m)
	Sets the maximum failures until termination.
unsigned int	getMaxFailures () const
	Retrieve the maximum consecutive failure limit.
double	getDenseDeltaFraction () const
	Retrieve the dense graph interface support delta.
double	getSparseDeltaFraction () const
	Retrieve the sparse graph visibility range delta.
double	getStretchFactor () const
	Retrieve the spanner's set stretch factor.
void	constructRoadmap (const base::PlannerTerminationCondition &ptc)
	While the termination condition permits, construct the spanner graph.
void	constructRoadmap (const base::PlannerTerminationCondition &ptc, bool stopOnMaxFail)
	While the termination condition permits, construct the spanner graph. If stopOnMaxFail is true, the function also terminates when the failure limit set by setMaxFailures() is reached.
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. Start and goal states from the currently specified ProblemDefinition are cached. This means that between calls to solve(), input states are only added, not removed. When using PRM as a multi-query planner, the input states should be however cleared, without clearing the roadmap itself. This can be done using the clearQuery() function.
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 PRM.
void	clear () override
	Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() will ignore all previous work.
template<template< typename T > class NN>
void	setNearestNeighbors ()
	Set a different nearest neighbors datastructure.
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.
const Graph &	getRoadmap () const
	Retrieve the computed roadmap.
unsigned int	milestoneCount () const
	Get the number of vertices in the sparse roadmap.
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	printDebug (std::ostream &out=std::cout) const
	Print debug information about planner.
std::string	getIterationCount () const
std::string	getBestCost () const
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
void	freeMemory ()
	Free all the memory allocated by the planner.
void	checkQueryStateInitialization ()
	Check that the query vertex is initialized (used for internal nearest neighbor searches)
bool	checkAddCoverage (const base::State *qNew, std::vector< Vertex > &visibleNeighborhood)
	Checks to see if the sample needs to be added to ensure coverage of the space.
bool	checkAddConnectivity (const base::State *qNew, std::vector< Vertex > &visibleNeighborhood)
	Checks to see if the sample needs to be added to ensure connectivity.
bool	checkAddInterface (const base::State *qNew, std::vector< Vertex > &graphNeighborhood, std::vector< Vertex > &visibleNeighborhood)
	Checks to see if the current sample reveals the existence of an interface, and if so, tries to bridge it.
bool	checkAddPath (Vertex v)
	Checks vertex v for short paths through its region and adds when appropriate.
void	resetFailures ()
	A reset function for resetting the failures count.
void	findGraphNeighbors (base::State *st, std::vector< Vertex > &graphNeighborhood, std::vector< Vertex > &visibleNeighborhood)
	Finds visible nodes in the graph near st.
void	approachGraph (Vertex v)
	Approaches the graph from a given vertex.
Vertex	findGraphRepresentative (base::State *st)
	Finds the representative of the input state, st
void	findCloseRepresentatives (base::State *workArea, const base::State *qNew, Vertex qRep, std::map< Vertex, base::State * > &closeRepresentatives, const base::PlannerTerminationCondition &ptc)
	Finds representatives of samples near qNew_ which are not his representative.
void	updatePairPoints (Vertex rep, const base::State *q, Vertex r, const base::State *s)
	High-level method which updates pair point information for repV_ with neighbor r.
void	computeVPP (Vertex v, Vertex vp, std::vector< Vertex > &VPPs)
	Computes all nodes which qualify as a candidate v" for v and vp.
void	computeX (Vertex v, Vertex vp, Vertex vpp, std::vector< Vertex > &Xs)
	Computes all nodes which qualify as a candidate x for v, v', and v".
VertexPair	index (Vertex vp, Vertex vpp)
	Rectifies indexing order for accessing the vertex data.
InterfaceData &	getData (Vertex v, Vertex vp, Vertex vpp)
	Retrieves the Vertex data associated with v,vp,vpp.
void	distanceCheck (Vertex rep, const base::State *q, Vertex r, const base::State *s, Vertex rp)
	Performs distance checking for the candidate new state, q against the current information.
void	abandonLists (base::State *st)
	When a new guard is added at state st, finds all guards who must abandon their interface information and deletes that information.
Vertex	addGuard (base::State *state, GuardType type)
	Construct a guard for a given state (state) and store it in the nearest neighbors data structure.
void	connectGuards (Vertex v, Vertex vp)
	Connect two guards in the roadmap.
bool	haveSolution (const std::vector< Vertex > &starts, const std::vector< Vertex > &goals, base::PathPtr &solution)
	Check if there exists a solution, i.e., there exists a pair of milestones such that the first is in start and the second is in goal, and the two milestones are in the same connected component. If a solution is found, the path is saved.
void	checkForSolution (const base::PlannerTerminationCondition &ptc, base::PathPtr &solution)
bool	reachedTerminationCriterion () const
	Returns true if we have reached the iteration failures limit, maxFailures_ or if a solution was added.
bool	reachedFailureLimit () const
	Returns whether we have reached the iteration failures limit, maxFailures_.
base::PathPtr	constructSolution (Vertex start, Vertex goal) const
	Given two milestones from the same connected component, construct a path connecting them and set it as the solution.
bool	sameComponent (Vertex m1, Vertex m2)
	Check if two milestones (m1 and m2) are part of the same connected component. This is not a const function since we use incremental connected components from boost.
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
base::ValidStateSamplerPtr	sampler_
	Sampler user for generating valid samples in the state space.
std::shared_ptr< NearestNeighbors< Vertex > >	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.
Vertex	queryVertex_
	Vertex for performing nearest neighbor queries.
double	stretchFactor_ {3.}
	Stretch Factor as per graph spanner literature (multiplicative bound on path quality)
double	sparseDeltaFraction_ {.25}
	Maximum visibility range for nodes in the graph as a fraction of maximum extent.
double	denseDeltaFraction_ {.001}
	Maximum range for allowing two samples to support an interface as a fraction of maximum extent.
unsigned int	maxFailures_ {5000}
	The number of consecutive failures to add to the graph before termination.
unsigned int	nearSamplePoints_
	Number of sample points to use when trying to detect interfaces.
boost::property_map< Graph, vertex_state_t >::type	stateProperty_
	Access to the internal base::state at each Vertex.
PathSimplifierPtr	psimp_
	A path simplifier used to simplify dense paths added to the graph.
boost::property_map< Graph, boost::edge_weight_t >::type	weightProperty_
	Access to the weights of each Edge.
boost::property_map< Graph, vertex_color_t >::type	colorProperty_
	Access to the colors for the vertices.
boost::property_map< Graph, vertex_interface_data_t >::type	interfaceDataProperty_
	Access to the interface pair information for the vertices.
boost::disjoint_sets< boost::property_map< Graph, boost::vertex_rank_t >::type, boost::property_map< Graph, boost::vertex_predecessor_t >::type >	disjointSets_
	Data structure that maintains the connected components.
RNG	rng_
	Random number generator.
bool	addedSolution_ {false}
	A flag indicating that a solution has been added during solve()
unsigned int	consecutiveFailures_ {0}
	A counter for the number of consecutive failed iterations of the algorithm.
double	sparseDelta_ {0.}
	Maximum visibility range for nodes in the graph.
double	denseDelta_ {0.}
	Maximum range for allowing two samples to support an interface.
std::mutex	graphMutex_
	Mutex to guard access to the Graph member (g_)
base::OptimizationObjectivePtr	opt_
	Objective cost function for PRM graph edges.
long unsigned int	iterations_ {0ul}
	A counter for the number of iterations of the algorithm.
base::Cost	bestCost_ {std::numeric_limits<double>::quiet_NaN()}
	Best cost found so far by algorithm.
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.

Detailed Description

SPArse Roadmap Spanner Version 2.0

Short description

SPARStwo is a variant of the SPARS algorithm which removes the dependency on having the dense graph, D. It works through similar mechanics, but uses a different approach to identifying interfaces and computing shortest paths through said interfaces.

External documentation

A. Dobson, K. Bekris, Improving Sparse Roadmap Spanners, IEEE International Conference on Robotics and Automation (ICRA) May 2013. [PDF]

Definition at line 141 of file SPARStwo.h.

Member Typedef Documentation

Graph

using ompl::geometric::SPARStwo::Graph = boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS, boost::property< vertex_state_t, base::State *, boost::property< boost::vertex_predecessor_t, VertexIndexType, boost::property<boost::vertex_rank_t, VertexIndexType, boost::property<vertex_color_t, GuardType, boost::property<vertex_interface_data_t, InterfaceHash> >> >>, boost::property<boost::edge_weight_t, base::Cost> >

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.

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 309 of file SPARStwo.h.

Member Function Documentation

checkForSolution()

void ompl::geometric::SPARStwo::checkForSolution ( const base::PlannerTerminationCondition &  ptc, base::PathPtr &  solution  )

protected

Thread that checks for solution

Definition at line 365 of file SPARStwo.cpp.

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

• ompl/geometric/planners/prm/SPARStwo.h
• ompl/geometric/planners/prm/src/SPARStwo.cpp