STRIDE.cpp
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34 
35 /* Author: Bryant Gipson, Mark Moll, Ioan Sucan */
36 
37 #include "ompl/geometric/planners/stride/STRIDE.h"
38 // enable sampling from the GNAT data structure
39 #define GNAT_SAMPLER
40 #include "ompl/datastructures/NearestNeighborsGNAT.h"
41 #include "ompl/base/goals/GoalSampleableRegion.h"
42 #include "ompl/tools/config/SelfConfig.h"
43 #include <limits>
44 #include <cassert>
45 
46 ompl::geometric::STRIDE::STRIDE(const base::SpaceInformationPtr &si, bool useProjectedDistance, unsigned int degree,
47  unsigned int minDegree, unsigned int maxDegree, unsigned int maxNumPtsPerLeaf,
48  double estimatedDimension)
49  : base::Planner(si, "STRIDE")
50  , useProjectedDistance_(useProjectedDistance)
51  , degree_(degree)
52  , minDegree_(minDegree)
53  , maxDegree_(maxDegree)
54  , maxNumPtsPerLeaf_(maxNumPtsPerLeaf)
55  , estimatedDimension_(estimatedDimension)
56 {
58 
59  if (estimatedDimension_ < 1.)
60  estimatedDimension_ = si->getStateDimension();
61 
62  Planner::declareParam<double>("range", this, &STRIDE::setRange, &STRIDE::getRange, "0.:1.:10000.");
63  Planner::declareParam<double>("goal_bias", this, &STRIDE::setGoalBias, &STRIDE::getGoalBias, "0.:.05:1.");
64  Planner::declareParam<bool>("use_projected_distance", this, &STRIDE::setUseProjectedDistance,
66  Planner::declareParam<unsigned int>("degree", this, &STRIDE::setDegree, &STRIDE::getDegree, "2:20");
67  Planner::declareParam<unsigned int>("max_degree", this, &STRIDE::setMaxDegree, &STRIDE::getMaxDegree, "2:20");
68  Planner::declareParam<unsigned int>("min_degree", this, &STRIDE::setMinDegree, &STRIDE::getMinDegree, "2:20");
69  Planner::declareParam<unsigned int>("max_pts_per_leaf", this, &STRIDE::setMaxNumPtsPerLeaf,
70  &STRIDE::getMaxNumPtsPerLeaf, "1:200");
71  Planner::declareParam<double>("estimated_dimension", this, &STRIDE::setEstimatedDimension,
73  Planner::declareParam<double>("min_valid_path_fraction", this, &STRIDE::setMinValidPathFraction,
74  &STRIDE::getMinValidPathFraction, "0.:.05:1.");
75 }
76 
77 ompl::geometric::STRIDE::~STRIDE()
78 {
79  freeMemory();
80 }
81 
83 {
84  Planner::setup();
88  setupTree();
89 }
90 
92 {
93  tree_.reset(
96  tree_->setDistanceFunction([this](const Motion *a, const Motion *b)
97  {
98  return projectedDistanceFunction(a, b);
99  });
100  else
101  tree_->setDistanceFunction([this](const Motion *a, const Motion *b)
102  {
103  return distanceFunction(a, b);
104  });
105 }
106 
108 {
109  Planner::clear();
110  sampler_.reset();
111  freeMemory();
112  setupTree();
113 }
114 
116 {
117  if (tree_)
118  {
119  std::vector<Motion *> motions;
120  tree_->list(motions);
121  for (auto &motion : motions)
122  {
123  if (motion->state)
124  si_->freeState(motion->state);
125  delete motion;
126  }
127  tree_.reset();
128  }
129 }
130 
132 {
133  checkValidity();
134  base::Goal *goal = pdef_->getGoal().get();
135  auto *goal_s = dynamic_cast<base::GoalSampleableRegion *>(goal);
136 
137  while (const base::State *st = pis_.nextStart())
138  {
139  auto *motion = new Motion(si_);
140  si_->copyState(motion->state, st);
141  addMotion(motion);
142  }
143 
144  if (tree_->size() == 0)
145  {
146  OMPL_ERROR("%s: There are no valid initial states!", getName().c_str());
148  }
149 
150  if (!sampler_)
151  sampler_ = si_->allocValidStateSampler();
152 
153  OMPL_INFORM("%s: Starting planning with %u states already in datastructure", getName().c_str(), tree_->size());
154 
155  Motion *solution = nullptr;
156  Motion *approxsol = nullptr;
157  double approxdif = std::numeric_limits<double>::infinity();
158  base::State *xstate = si_->allocState();
159 
160  while (ptc == false)
161  {
162  /* Decide on a state to expand from */
163  Motion *existing = selectMotion();
164  assert(existing);
165 
166  /* sample random state (with goal biasing) */
167  if (goal_s && rng_.uniform01() < goalBias_ && goal_s->canSample())
168  goal_s->sampleGoal(xstate);
169  else if (!sampler_->sampleNear(xstate, existing->state, maxDistance_))
170  continue;
171 
172  std::pair<base::State *, double> fail(xstate, 0.0);
173  bool keep = si_->checkMotion(existing->state, xstate, fail) || fail.second > minValidPathFraction_;
174 
175  if (keep)
176  {
177  /* create a motion */
178  auto *motion = new Motion(si_);
179  si_->copyState(motion->state, xstate);
180  motion->parent = existing;
181 
182  addMotion(motion);
183  double dist = 0.0;
184  bool solved = goal->isSatisfied(motion->state, &dist);
185  if (solved)
186  {
187  approxdif = dist;
188  solution = motion;
189  break;
190  }
191  if (dist < approxdif)
192  {
193  approxdif = dist;
194  approxsol = motion;
195  }
196  }
197  }
198 
199  bool solved = false;
200  bool approximate = false;
201  if (solution == nullptr)
202  {
203  solution = approxsol;
204  approximate = true;
205  }
206 
207  if (solution != nullptr)
208  {
209  /* construct the solution path */
210  std::vector<Motion *> mpath;
211  while (solution != nullptr)
212  {
213  mpath.push_back(solution);
214  solution = solution->parent;
215  }
216 
217  /* set the solution path */
218  auto path(std::make_shared<PathGeometric>(si_));
219  for (int i = mpath.size() - 1; i >= 0; --i)
220  path->append(mpath[i]->state);
221  pdef_->addSolutionPath(path, approximate, approxdif, getName());
222  solved = true;
223  }
224 
225  si_->freeState(xstate);
226 
227  OMPL_INFORM("%s: Created %u states", getName().c_str(), tree_->size());
228 
229  return base::PlannerStatus(solved, approximate);
230 }
231 
233 {
234  tree_->add(motion);
235 }
236 
238 {
239  return tree_->sample(rng_);
240 }
241 
243 {
244  Planner::getPlannerData(data);
245 
246  std::vector<Motion *> motions;
247  tree_->list(motions);
248  for (auto &motion : motions)
249  {
250  if (motion->parent == nullptr)
251  data.addStartVertex(base::PlannerDataVertex(motion->state, 1));
252  else
253  data.addEdge(base::PlannerDataVertex(motion->parent->state, 1), base::PlannerDataVertex(motion->state, 1));
254  }
255 }
void setupTree()
Initialize GNAT data structure.
Definition: STRIDE.cpp:91
bool approximateSolutions
Flag indicating whether the planner is able to compute approximate solutions.
Definition: Planner.h:203
Object containing planner generated vertex and edge data. It is assumed that all vertices are unique...
Definition: PlannerData.h:174
double getEstimatedDimension() const
Get estimated dimension of the free space, which is needed to compute the sampling weight for a node ...
Definition: STRIDE.h:178
base::ProjectionEvaluatorPtr projectionEvaluator_
This algorithm can optionally use a projection to guide the exploration.
Definition: STRIDE.h:289
void freeMemory()
Free the memory allocated by this planner.
Definition: STRIDE.cpp:115
The definition of a motion.
Definition: STRIDE.h:238
double estimatedDimension_
Estimate of the local dimensionality of the free space around a state.
Definition: STRIDE.h:313
base::PlannerStatus solve(const base::PlannerTerminationCondition &ptc) override
Function that can solve the motion planning problem. This function can be called multiple times on th...
Definition: STRIDE.cpp:131
void setMinDegree(unsigned int minDegree)
Set minimum degree of a node in the GNAT.
Definition: STRIDE.h:137
void setEstimatedDimension(double estimatedDimension)
Set estimated dimension of the free space, which is needed to compute the sampling weight for a node ...
Definition: STRIDE.h:171
Abstract definition of goals.
Definition: Goal.h:62
Encapsulate a termination condition for a motion planner. Planners will call operator() to decide whe...
unsigned int minDegree_
Minimum degree of an internal node in the GNAT.
Definition: STRIDE.h:307
void setup() override
Perform extra configuration steps, if needed. This call will also issue a call to ompl::base::SpaceIn...
Definition: STRIDE.cpp:82
Geometric Near-neighbor Access Tree (GNAT), a data structure for nearest neighbor search...
bool useProjectedDistance_
Whether to use distance in the projection (instead of distance in the state space) for the GNAT...
Definition: STRIDE.h:303
ProblemDefinitionPtr pdef_
The user set problem definition.
Definition: Planner.h:409
unsigned int maxDegree_
Maximum degree of an internal node in the GNAT.
Definition: STRIDE.h:309
double projectedDistanceFunction(const Motion *a, const Motion *b) const
Compute distance between motions (actually distance between projections of contained states) ...
Definition: STRIDE.h:270
base::ValidStateSamplerPtr sampler_
Valid state sampler.
Definition: STRIDE.h:286
double uniform01()
Generate a random real between 0 and 1.
Definition: RandomNumbers.h:68
Base class for a vertex in the PlannerData structure. All derived classes must implement the clone an...
Definition: PlannerData.h:58
double getMinValidPathFraction() const
Get the value of the fraction set by setMinValidPathFraction()
Definition: STRIDE.h:210
Invalid start state or no start state specified.
Definition: PlannerStatus.h:56
Abstract definition of a goal region that can be sampled.
double getRange() const
Get the range the planner is using.
Definition: STRIDE.h:194
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.
Definition: STRIDE.h:319
unsigned int getMaxDegree() const
Set maximum degree of a node in the GNAT.
Definition: STRIDE.h:152
void setDegree(unsigned int degree)
Set desired degree of a node in the GNAT.
Definition: STRIDE.h:127
void setMaxNumPtsPerLeaf(unsigned int maxNumPtsPerLeaf)
Set maximum number of elements stored in a leaf node of the GNAT.
Definition: STRIDE.h:158
double distanceFunction(const Motion *a, const Motion *b) const
Compute distance between motions (actually distance between contained states)
Definition: STRIDE.h:264
#define OMPL_ERROR(fmt,...)
Log a formatted error string.
Definition: Console.h:64
double maxDistance_
The maximum length of a motion to be added to a tree.
Definition: STRIDE.h:299
bool getUseProjectedDistance() const
Return whether nearest neighbors are computed based on distances in a projection of the state rather ...
Definition: STRIDE.h:121
void clear() override
Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() wil...
Definition: STRIDE.cpp:107
A class to store the exit status of Planner::solve()
Definition: PlannerStatus.h:48
virtual bool addEdge(unsigned int v1, unsigned int v2, const PlannerDataEdge &edge=PlannerDataEdge(), Cost weight=Cost(1.0))
Adds a directed edge between the given vertex indexes. An optional edge structure and weight can be s...
A shared pointer wrapper for ompl::base::SpaceInformation.
unsigned int addStartVertex(const PlannerDataVertex &v)
Adds the given vertex to the graph data, and marks it as a start vertex. The vertex index is returned...
Definition of an abstract state.
Definition: State.h:49
void setRange(double distance)
Set the range the planner is supposed to use.
Definition: STRIDE.h:188
virtual void checkValidity()
Check to see if the planner is in a working state (setup has been called, a goal was set...
Definition: Planner.cpp:101
virtual bool isSatisfied(const State *st) const =0
Return true if the state satisfies the goal constraints.
PlannerInputStates pis_
Utility class to extract valid input states.
Definition: Planner.h:412
unsigned int degree_
Desired degree of an internal node in the GNAT.
Definition: STRIDE.h:305
PlannerSpecs specs_
The specifications of the planner (its capabilities)
Definition: Planner.h:418
const State * nextStart()
Return the next valid start state or nullptr if no more valid start states are available.
Definition: Planner.cpp:227
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.
Definition: STRIDE.cpp:46
void configureProjectionEvaluator(base::ProjectionEvaluatorPtr &proj)
If proj is undefined, it is set to the default projection reported by base::StateSpace::getDefaultPro...
Definition: SelfConfig.cpp:231
const std::string & getName() const
Get the name of the planner.
Definition: Planner.cpp:56
Motion * selectMotion()
Select a motion to continue the expansion of the tree from.
Definition: STRIDE.cpp:237
void configurePlannerRange(double &range)
Compute what a good length for motion segments is.
Definition: SelfConfig.cpp:225
This class contains methods that automatically configure various parameters for motion planning...
Definition: SelfConfig.h:59
unsigned int getDegree() const
Get desired degree of a node in the GNAT.
Definition: STRIDE.h:132
double getGoalBias() const
Get the goal bias the planner is using.
Definition: STRIDE.h:106
double goalBias_
The fraction of time the goal is picked as the state to expand towards (if such a state is available)...
Definition: STRIDE.h:296
void getPlannerData(base::PlannerData &data) const override
Get information about the current run of the motion planner. Repeated calls to this function will upd...
Definition: STRIDE.cpp:242
SpaceInformationPtr si_
The space information for which planning is done.
Definition: Planner.h:406
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).
Definition: STRIDE.h:204
base::State * state
The state contained by the motion.
Definition: STRIDE.h:251
unsigned int getMinDegree() const
Get minimum degree of a node in the GNAT.
Definition: STRIDE.h:142
unsigned int maxNumPtsPerLeaf_
Maximum number of points stored in a leaf node in the GNAT.
Definition: STRIDE.h:311
unsigned int getMaxNumPtsPerLeaf() const
Get maximum number of elements stored in a leaf node of the GNAT.
Definition: STRIDE.h:164
void setUseProjectedDistance(bool useProjectedDistance)
Set whether nearest neighbors are computed based on distances in a projection of the state rather dis...
Definition: STRIDE.h:114
void setMaxDegree(unsigned int maxDegree)
Set maximum degree of a node in the GNAT.
Definition: STRIDE.h:147
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.
Definition: STRIDE.h:100
void addMotion(Motion *motion)
Add a motion to the exploration tree.
Definition: STRIDE.cpp:232
#define OMPL_INFORM(fmt,...)
Log a formatted information string.
Definition: Console.h:68
boost::scoped_ptr< NearestNeighborsGNAT< Motion * > > tree_
The exploration tree constructed by this algorithm.
Definition: STRIDE.h:292
RNG rng_
The random number generator.
Definition: STRIDE.h:322