An SE(2) state space where distance is measured by the length of Dubins curves. More...
#include <ompl/base/spaces/DubinsStateSpace.h>
Classes  
class  DubinsPath 
Complete description of a Dubins path. More...  
Public Types  
enum  DubinsPathSegmentType { DUBINS_LEFT = 0, DUBINS_STRAIGHT = 1, DUBINS_RIGHT = 2 } 
The Dubins path segment type.  
Public Types inherited from ompl::base::CompoundStateSpace  
using  StateType = ompl::base::CompoundState 
Define the type of state allocated by this state space.  
Public Types inherited from ompl::base::StateSpace  
enum  SanityChecks { STATESPACE_DISTANCE_DIFFERENT_STATES = (1 << 1), STATESPACE_DISTANCE_SYMMETRIC = (1 << 2), STATESPACE_INTERPOLATION = (1 << 3), STATESPACE_TRIANGLE_INEQUALITY = (1 << 4), STATESPACE_DISTANCE_BOUND = (1 << 5), STATESPACE_RESPECT_BOUNDS = (1 << 6), STATESPACE_ENFORCE_BOUNDS_NO_OP = (1 << 7), STATESPACE_SERIALIZATION = (1 << 8) } 
Flags to use in a bit mask for state space sanity checks. Some basic checks do not have flags associated (they are always executed; for example, whether copyState() works as expected) More...  
using  StateType = ompl::base::State 
Define the type of state allocated by this space.  
Public Member Functions  
DubinsStateSpace (double turningRadius=1.0, bool isSymmetric=false)  
bool  isMetricSpace () const override 
Return true if the distance function associated with the space is a metric.  
double  distance (const State *state1, const State *state2) const override 
Computes distance between two states. This function satisfies the properties of a metric if isMetricSpace() is true, and its return value will always be between 0 and getMaximumExtent()  
void  interpolate (const State *from, const State *to, double t, State *state) const override 
Computes the state that lies at time t in [0, 1] on the segment that connects from state to to state. The memory location of state is not required to be different from the memory of either from or to.  
virtual void  interpolate (const State *from, const State *to, double t, bool &firstTime, DubinsPath &path, State *state) const 
bool  hasSymmetricDistance () const override 
Check if the distance function on this state space is symmetric, i.e. distance(s1,s2) = distance(s2,s1). Default implementation returns true.  
bool  hasSymmetricInterpolate () const override 
Check if the interpolation function on this state space is symmetric, i.e. interpolate(from, to, t, state) = interpolate(to, from, 1t, state). Default implementation returns true.  
void  sanityChecks () const override 
Convenience function that allows derived state spaces to choose which checks should pass (see SanityChecks flags) and how strict the checks are. This just calls sanityChecks() with some default arguments.  
DubinsPath  dubins (const State *state1, const State *state2) const 
Return the shortest Dubins path from SE(2) state state1 to SE(2) state state2.  
Public Member Functions inherited from ompl::base::SE2StateSpace  
void  setBounds (const RealVectorBounds &bounds) 
Set the bounds of this state space. This defines the range of the space in which sampling is performed. More...  
const RealVectorBounds &  getBounds () const 
Get the bounds for this state space. More...  
State *  allocState () const override 
Allocate a state that can store a point in the described space.  
void  freeState (State *state) const override 
Free the memory of the allocated state.  
void  registerProjections () override 
Register the projections for this state space. Usually, this is at least the default projection. These are implicit projections, set by the implementation of the state space. This is called by setup().  
Public Member Functions inherited from ompl::base::CompoundStateSpace  
CompoundStateSpace ()  
Construct an empty compound state space.  
CompoundStateSpace (const std::vector< StateSpacePtr > &components, const std::vector< double > &weights)  
Construct a compound state space from a list of subspaces (components) and their corresponding weights (weights)  
template<class T >  
T *  as (const unsigned int index) const 
Cast a component of this instance to a desired type. More...  
template<class T >  
T *  as (const std::string &name) const 
Cast a component of this instance to a desired type. More...  
bool  isCompound () const override 
Check if the state space is compound.  
bool  isHybrid () const override 
Check if this is a hybrid state space (i.e., both discrete and continuous components exist)  
void  printState (const State *state, std::ostream &out) const override 
Print a state to a stream.  
void  printSettings (std::ostream &out) const override 
Print the settings for this state space to a stream.  
void  computeLocations () override 
Compute the location information for various components of the state space. Either this function or setup() must be called before any calls to getValueAddressAtName(), getValueAddressAtLocation() (and other functions where those are used).  
void  setup () override 
Perform final setup steps. This function is automatically called by the SpaceInformation. If any default projections are to be registered, this call will set them and call their setup() functions. It is safe to call this function multiple times. At a subsequent call, projections that have been previously user configured are not reinstantiated, but their setup() method is still called.  
void  addSubspace (const StateSpacePtr &component, double weight) 
Adds a new state space as part of the compound state space. For computing distances within the compound state space, the weight of the component also needs to be specified.  
unsigned int  getSubspaceCount () const 
Get the number of state spaces that make up the compound state space.  
const StateSpacePtr &  getSubspace (unsigned int index) const 
Get a specific subspace from the compound state space.  
const StateSpacePtr &  getSubspace (const std::string &name) const 
Get a specific subspace from the compound state space.  
unsigned int  getSubspaceIndex (const std::string &name) const 
Get the index of a specific subspace from the compound state space.  
bool  hasSubspace (const std::string &name) const 
Check if a specific subspace is contained in this state space.  
double  getSubspaceWeight (unsigned int index) const 
Get the weight of a subspace from the compound state space (used in distance computation)  
double  getSubspaceWeight (const std::string &name) const 
Get the weight of a subspace from the compound state space (used in distance computation)  
void  setSubspaceWeight (unsigned int index, double weight) 
Set the weight of a subspace in the compound state space (used in distance computation)  
void  setSubspaceWeight (const std::string &name, double weight) 
Set the weight of a subspace in the compound state space (used in distance computation)  
const std::vector< StateSpacePtr > &  getSubspaces () const 
Get the list of components.  
const std::vector< double > &  getSubspaceWeights () const 
Get the list of component weights.  
bool  isLocked () const 
Return true if the state space is locked. A value of true means that no further spaces can be added as components.  
void  lock () 
Lock this state space. This means no further spaces can be added as components. This function can be for instance called from the constructor of a state space that inherits from CompoundStateSpace to prevent the user to add further components.  
StateSamplerPtr  allocSubspaceStateSampler (const StateSpace *subspace) const override 
Allocate a sampler that actually samples only components that are part of subspace.  
unsigned int  getDimension () const override 
Get the dimension of the space (not the dimension of the surrounding ambient space)  
double  getMaximumExtent () const override 
Get the maximum value a call to distance() can return (or an upper bound). For unbounded state spaces, this function can return infinity. More...  
double  getMeasure () const override 
Get a measure of the space (this can be thought of as a generalization of volume)  
void  enforceBounds (State *state) const override 
Bring the state within the bounds of the state space. For unbounded spaces this function can be a noop.  
bool  satisfiesBounds (const State *state) const override 
Check if a state is inside the bounding box. For unbounded spaces this function can always return true.  
void  copyState (State *destination, const State *source) const override 
Copy a state to another. The memory of source and destination should NOT overlap. More...  
unsigned int  getSerializationLength () const override 
Get the number of chars in the serialization of a state in this space.  
void  serialize (void *serialization, const State *state) const override 
Write the binary representation of state to serialization.  
void  deserialize (State *state, const void *serialization) const override 
Read the binary representation of a state from serialization and write it to state.  
double  distance (const State *state1, const State *state2) const override 
Computes distance between two states. This function satisfies the properties of a metric if isMetricSpace() is true, and its return value will always be between 0 and getMaximumExtent()  
void  setLongestValidSegmentFraction (double segmentFraction) override 
When performing discrete validation of motions, the length of the longest segment that does not require state validation needs to be specified. This function sets this length as a fraction of the space's maximum extent. The call is passed to all contained subspaces.  
unsigned int  validSegmentCount (const State *state1, const State *state2) const override 
Count how many segments of the "longest valid length" fit on the motion from state1 to state2. This is the max() of the counts returned by contained subspaces.  
bool  equalStates (const State *state1, const State *state2) const override 
Checks whether two states are equal.  
void  interpolate (const State *from, const State *to, double t, State *state) const override 
Computes the state that lies at time t in [0, 1] on the segment that connects from state to to state. The memory location of state is not required to be different from the memory of either from or to.  
StateSamplerPtr  allocDefaultStateSampler () const override 
Allocate an instance of the default uniform state sampler for this space.  
State *  allocState () const override 
Allocate a state that can store a point in the described space.  
void  freeState (State *state) const override 
Free the memory of the allocated state.  
double *  getValueAddressAtIndex (State *state, unsigned int index) const override 
Many states contain a number of double values. This function provides a means to get the memory address of a double value from state state located at position index. The first double value is returned for index = 0. If index is too large (does not point to any double values in the state), the return value is nullptr. More...  
Public Member Functions inherited from ompl::base::StateSpace  
StateSpace (const StateSpace &)=delete  
StateSpace &  operator= (const StateSpace &)=delete 
StateSpace ()  
Constructor. Assigns a unique name to the space.  
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...  
virtual bool  isDiscrete () const 
Check if the set of states is discrete. More...  
const std::string &  getName () const 
Get the name of the state space.  
void  setName (const std::string &name) 
Set the name of the state space.  
int  getType () const 
Get the type of the state space. The type can be used to verify whether two space instances are of the same type (e.g., SO2)  
bool  includes (const StateSpacePtr &other) const 
Return true if other is a space included (perhaps equal, perhaps a subspace) in this one.  
bool  includes (const StateSpace *other) const 
Return true if other is a space included (perhaps equal, perhaps a subspace) in this one.  
bool  covers (const StateSpacePtr &other) const 
Return true if other is a space that is either included (perhaps equal, perhaps a subspace) in this one, or all of its subspaces are included in this one.  
bool  covers (const StateSpace *other) const 
Return true if other is a space that is either included (perhaps equal, perhaps a subspace) in this one, or all of its subspaces are included in this one.  
ParamSet &  params () 
Get the parameters for this space.  
const ParamSet &  params () const 
Get the parameters for this space.  
virtual double  getLongestValidSegmentFraction () const 
When performing discrete validation of motions, the length of the longest segment that does not require state validation needs to be specified. This function returns this length, for this state space, as a fraction of the space's maximum extent.  
virtual void  setValidSegmentCountFactor (unsigned int factor) 
Set factor to be the value to multiply the return value of validSegmentCount(). By default, this value is 1. The higher the value, the smaller the size of the segments considered valid. The effect of this function is immediate (setup() does not need to be called).  
virtual unsigned int  getValidSegmentCountFactor () const 
Get the value used to multiply the return value of validSegmentCount().  
virtual double  getLongestValidSegmentLength () const 
Get the longest valid segment at the time setup() was called.  
virtual void  computeSignature (std::vector< int > &signature) const 
Compute an array of ints that uniquely identifies the structure of the state space. The first element of the signature is the number of integers that follow.  
State *  cloneState (const State *source) const 
Clone a state.  
virtual StateSamplerPtr  allocStateSampler () const 
Allocate an instance of the state sampler for this space. This sampler will be allocated with the sampler allocator that was previously specified by setStateSamplerAllocator() or, if no sampler allocator was specified, allocDefaultStateSampler() is called.  
void  setStateSamplerAllocator (const StateSamplerAllocator &ssa) 
Set the sampler allocator to use.  
void  clearStateSamplerAllocator () 
Clear the state sampler allocator (reset to default)  
const double *  getValueAddressAtIndex (const State *state, unsigned int index) const 
Const variant of the same function as above;.  
const std::vector< ValueLocation > &  getValueLocations () const 
Get the locations of values of type double contained in a state from this space. The order of the values is consistent with getValueAddressAtIndex(). The setup() function must have been previously called.  
const std::map< std::string, ValueLocation > &  getValueLocationsByName () const 
Get the named locations of values of type double contained in a state from this space. The setup() function must have been previously called.  
double *  getValueAddressAtLocation (State *state, const ValueLocation &loc) const 
Get a pointer to the double value in state that loc points to.  
const double *  getValueAddressAtLocation (const State *state, const ValueLocation &loc) const 
Const variant of the same function as above;.  
double *  getValueAddressAtName (State *state, const std::string &name) const 
Get a pointer to the double value in state that name points to.  
const double *  getValueAddressAtName (const State *state, const std::string &name) const 
Const variant of the same function as above;.  
virtual void  copyToReals (std::vector< double > &reals, const State *source) const 
Copy all the real values from a state source to the array reals using getValueAddressAtLocation()  
virtual void  copyFromReals (State *destination, const std::vector< double > &reals) const 
Copy the values from reals to the state destination using getValueAddressAtLocation()  
void  registerProjection (const std::string &name, const ProjectionEvaluatorPtr &projection) 
Register a projection for this state space under a specified name.  
void  registerDefaultProjection (const ProjectionEvaluatorPtr &projection) 
Register the default projection for this state space.  
ProjectionEvaluatorPtr  getProjection (const std::string &name) const 
Get the projection registered under a specific name.  
ProjectionEvaluatorPtr  getDefaultProjection () const 
Get the default projection.  
bool  hasProjection (const std::string &name) const 
Check if a projection with a specified name is available.  
bool  hasDefaultProjection () const 
Check if a default projection is available.  
const std::map< std::string, ProjectionEvaluatorPtr > &  getRegisteredProjections () const 
Get all the registered projections.  
StateSamplerPtr  allocSubspaceStateSampler (const StateSpacePtr &subspace) const 
Allocate a sampler that actually samples only components that are part of subspace.  
State *  getSubstateAtLocation (State *state, const SubstateLocation &loc) const 
Get the substate of state that is pointed to by loc.  
const State *  getSubstateAtLocation (const State *state, const SubstateLocation &loc) const 
Get the substate of state that is pointed to by loc.  
const std::map< std::string, SubstateLocation > &  getSubstateLocationsByName () const 
Get the list of known substate locations (keys of the map corrspond to names of subspaces)  
void  getCommonSubspaces (const StateSpacePtr &other, std::vector< std::string > &subspaces) const 
Get the set of subspaces that this space and other have in common. The computed list of subspaces does not contain spaces that cover each other, even though they may be common, as that is redundant information.  
void  getCommonSubspaces (const StateSpace *other, std::vector< std::string > &subspaces) const 
Get the set of subspaces that this space and other have in common. The computed list of subspaces does not contain spaces that cover each other, even though they may be common, as that is redundant information.  
virtual void  printProjections (std::ostream &out) const 
Print the list of registered projections. This function is also called by printSettings()  
virtual void  sanityChecks (double zero, double eps, unsigned int flags) const 
Perform sanity checks for this state space. Throws an exception if failures are found. More...  
void  diagram (std::ostream &out) const 
Print a Graphviz digraph that represents the containment diagram for the state space.  
void  list (std::ostream &out) const 
Print the list of all contained state space instances.  
Static Public Attributes  
static const DubinsPathSegmentType  dubinsPathType [6][3] 
Dubins path types. More...  
Protected Member Functions  
virtual void  interpolate (const State *from, const DubinsPath &path, double t, State *state) const 
Protected Member Functions inherited from ompl::base::CompoundStateSpace  
void  allocStateComponents (CompoundState *state) const 
Allocate the state components. Called by allocState(). Usually called by derived state spaces.  
Protected Attributes  
double  rho_ 
Turning radius.  
bool  isSymmetric_ 
Whether the distance is "symmetrized". More...  
Protected Attributes inherited from ompl::base::CompoundStateSpace  
std::vector< StateSpacePtr >  components_ 
The state spaces that make up the compound state space.  
unsigned int  componentCount_ {0u} 
The number of components.  
std::vector< double >  weights_ 
The weight assigned to each component of the state space when computing the compound distance.  
double  weightSum_ {0.0} 
The sum of all the weights in weights_.  
bool  locked_ {false} 
Flag indicating whether adding further components is allowed or not.  
Protected Attributes inherited from ompl::base::StateSpace  
int  type_ 
A type assigned for this state space.  
StateSamplerAllocator  ssa_ 
An optional state sampler allocator.  
double  maxExtent_ 
The extent of this space at the time setup() was called.  
double  longestValidSegmentFraction_ 
The fraction of the longest valid segment.  
double  longestValidSegment_ 
The longest valid segment at the time setup() was called.  
unsigned int  longestValidSegmentCountFactor_ 
The factor to multiply the value returned by validSegmentCount(). Rarely used but useful for things like doubling the resolution.  
std::map< std::string, ProjectionEvaluatorPtr >  projections_ 
List of available projections.  
ParamSet  params_ 
The set of parameters for this space.  
std::vector< ValueLocation >  valueLocationsInOrder_ 
The value locations for all varliables of type double contained in a state; The locations point to values in the same order as that returned by getValueAddressAtIndex()  
std::map< std::string, ValueLocation >  valueLocationsByName_ 
All the known value locations, by name. The names of state spaces access the first element of a state. RealVectorStateSpace dimensions are used to access individual dimensions.  
std::map< std::string, SubstateLocation >  substateLocationsByName_ 
All the known substat locations, by name.  
Additional Inherited Members  
Static Public Member Functions inherited from ompl::base::StateSpace  
static void  Diagram (std::ostream &out) 
Print a Graphviz digraph that represents the containment diagram for all the instantiated state spaces.  
static void  List (std::ostream &out) 
Print the list of available state space instances.  
Static Protected Attributes inherited from ompl::base::StateSpace  
static const std::string  DEFAULT_PROJECTION_NAME = "" 
The name used for the default projection.  
Detailed Description
An SE(2) state space where distance is measured by the length of Dubins curves.
Note that this Dubins distance is not a proper distance metric, so nearest neighbor methods that rely on distance() being a metric (such as ompl::NearestNeighborsGNAT) will not always return the true nearest neighbors or get stuck in an infinite loop.
The notation and solutions in the code are taken from:
A.M. Shkel and V. Lumelsky, “Classification of the Dubins set,” Robotics and Autonomous Systems, 34(4):179202, 2001. DOI: 10.1016/S09218890(00)001275
The classification scheme described there is not actually used, since it only applies to “long” paths.
Definition at line 125 of file DubinsStateSpace.h.
Member Data Documentation
◆ dubinsPathType

static 
Dubins path types.
Definition at line 167 of file DubinsStateSpace.h.
◆ isSymmetric_

protected 
Whether the distance is "symmetrized".
If true the distance from state s1 to state s2 is the same as the distance from s2 to s1. This is done by taking the minimum length of the Dubins curves that connect s1 to s2 and s2 to s1. If isSymmetric_ is true, then the distance no longer satisfies the triangle inequality.
Definition at line 248 of file DubinsStateSpace.h.
The documentation for this class was generated from the following files:
 ompl/base/spaces/DubinsStateSpace.h
 ompl/base/spaces/src/DubinsStateSpace.cpp