ompl::geometric::STRIDE Class Reference

Search Tree with Resolution Independent Density Estimation. More...

#include <ompl/geometric/planners/stride/STRIDE.h>

Inheritance diagram for ompl::geometric::STRIDE:

Classes

class  Motion
The definition of a motion. More...

Public Member Functions

STRIDE (const base::SpaceInformationPtr &si, bool useProjectedDistance=false, unsigned int degree=16, unsigned int minDegree=12, unsigned int maxDegree=18, unsigned int maxNumPtsPerLeaf=6, double estimatedDimension=0.0)
Constructor.

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.

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). The function terminates if the call to ptc returns true.

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

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.

double getGoalBias () const
Get the goal bias the planner is using.

void setUseProjectedDistance (bool useProjectedDistance)
Set whether nearest neighbors are computed based on distances in a projection of the state rather distances in the state space itself.

bool getUseProjectedDistance () const
Return whether nearest neighbors are computed based on distances in a projection of the state rather distances in the state space itself.

void setDegree (unsigned int degree)
Set desired degree of a node in the GNAT.

unsigned int getDegree () const
Get desired degree of a node in the GNAT.

void setMinDegree (unsigned int minDegree)
Set minimum degree of a node in the GNAT.

unsigned int getMinDegree () const
Get minimum degree of a node in the GNAT.

void setMaxDegree (unsigned int maxDegree)
Set maximum degree of a node in the GNAT.

unsigned int getMaxDegree () const
Set maximum degree of a node in the GNAT.

void setMaxNumPtsPerLeaf (unsigned int maxNumPtsPerLeaf)
Set maximum number of elements stored in a leaf node of the GNAT.

unsigned int getMaxNumPtsPerLeaf () const
Get maximum number of elements stored in a leaf node of the GNAT.

void setEstimatedDimension (double estimatedDimension)
Set estimated dimension of the free space, which is needed to compute the sampling weight for a node in the GNAT.

double getEstimatedDimension () const
Get estimated dimension of the free space, which is needed to compute the sampling weight for a node in the GNAT.

void setRange (double distance)
Set the range the planner is supposed to use. More...

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

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 (between 0 and 1).

double getMinValidPathFraction () const
Get the value of the fraction set by setMinValidPathFraction()

void setProjectionEvaluator (const base::ProjectionEvaluatorPtr &projectionEvaluator)
Set the projection evaluator. This class is able to compute the projection of a given state.

void setProjectionEvaluator (const std::string &name)
Set the projection evaluator (select one from the ones registered with the state space).

const base::ProjectionEvaluatorPtrgetProjectionEvaluator () const
Get the projection evaluator.

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).

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

Planneroperator= (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 SpaceInformationPtrgetSpaceInformation () const
Get the space information this planner is using.

const ProblemDefinitionPtrgetProblemDefinition () const
Get the problem definition the planner is trying to solve.

const PlannerInputStatesgetPlannerInputStates () 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().

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 PlannerSpecsgetSpecs () 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.

ParamSetparams ()
Get the parameters for this planner.

const ParamSetparams () const
Get the parameters for this planner.

const PlannerProgressPropertiesgetPlannerProgressProperties () 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 the memory allocated by this planner.

void setupTree ()
Initialize GNAT data structure.

double distanceFunction (const Motion *a, const Motion *b) const
Compute distance between motions (actually distance between contained states)

double projectedDistanceFunction (const Motion *a, const Motion *b) const
Compute distance between motions (actually distance between projections of contained states)

Add a motion to the exploration tree.

MotionselectMotion ()
Select a motion to continue the expansion of the tree from.

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_
Valid state sampler.

base::ProjectionEvaluatorPtr projectionEvaluator_
This algorithm can optionally use a projection to guide the exploration.

boost::scoped_ptr< NearestNeighborsGNAT< Motion * > > tree_
The exploration tree constructed by this algorithm.

double goalBias_ {.05}
The fraction of time the goal is picked as the state to expand towards (if such a state is available)

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

bool useProjectedDistance_
Whether to use distance in the projection (instead of distance in the state space) for the GNAT.

unsigned int degree_
Desired degree of an internal node in the GNAT.

unsigned int minDegree_
Minimum degree of an internal node in the GNAT.

unsigned int maxDegree_
Maximum degree of an internal node in the GNAT.

unsigned int maxNumPtsPerLeaf_
Maximum number of points stored in a leaf node in the GNAT.

double estimatedDimension_
Estimate of the local dimensionality of the free space around a state.

double minValidPathFraction_ {.2}
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 is used only when extendWhileValid_ is true.

RNG rng_
The random number generator.

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.

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

typedef std::map< std::string, PlannerProgressPropertyPlannerProgressProperties
A dictionary which maps the name of a progress property to the function to be used for querying that property.

Detailed Description

Search Tree with Resolution Independent Density Estimation.

Short description
STRIDE (Search Tree with Resolution Independent Density Estimation) is a tree-based motion planner that attempts to detect the less explored area of the space through the use of a GNAT nearest-neighbor data structure. It is similar to EST, but unlike the EST implementation in OMPL does not require a projection. However, in case the state space has many dimensions, a projection can be specified and the GNAT can be built using distances in the projected space. This has the advantage over the EST implementation that no grid cell sizes have to be specified.
External documentation
B. Gipson, M. Moll, and L.E. Kavraki, Resolution independent density estimation for motion planning in high-dimensional spaces, in IEEE Intl. Conf. on Robotics and Automation, pp. 2429-2435, 2013. [PDF]

Definition at line 78 of file STRIDE.h.

◆ setRange()

 void ompl::geometric::STRIDE::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 188 of file STRIDE.h.

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