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:

List of all members.

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.
virtual void setup ()
 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 base::PlannerStatus 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 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.
virtual void clear ()
 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.
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::ProjectionEvaluatorPtr
getProjectionEvaluator () const
 Get the projection evaluator.
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).

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)
void addMotion (Motion *motion)
 Add a motion to the exploration tree.
MotionselectMotion ()
 Select a motion to continue the expansion of the tree from.

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_
 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.
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_
 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.

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]](http://dx.doi.org/10.1109/ICRA.2013.6630908)

Definition at line 80 of file STRIDE.h.


Member Function Documentation

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 191 of file STRIDE.h.


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