SST.h

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/* Authors: Zakary Littlefield */

#ifndef OMPL_GEOMETRIC_PLANNERS_SST_SST_
#define OMPL_GEOMETRIC_PLANNERS_SST_SST_

#include "ompl/geometric/planners/PlannerIncludes.h"
#include "ompl/datastructures/NearestNeighbors.h"

namespace ompl
{
    namespace geometric
    {
        class SST : public base::Planner
        {
        public:
            SST(const base::SpaceInformationPtr &si);

            ~SST() override;

            void setup() override;

            base::PlannerStatus solve(const base::PlannerTerminationCondition &ptc) override;

            void getPlannerData(base::PlannerData &data) const override;

            void clear() override;

            void setGoalBias(double goalBias)
            {
                goalBias_ = goalBias;
            }

            double getGoalBias() const
            {
                return goalBias_;
            }

            void setRange(double distance)
            {
                maxDistance_ = distance;
            }

            double getRange() const
            {
                return maxDistance_;
            }

            void setSelectionRadius(double selectionRadius)
            {
                selectionRadius_ = selectionRadius;
            }

            double getSelectionRadius() const
            {
                return selectionRadius_;
            }

            void setPruningRadius(double pruningRadius)
            {
                pruningRadius_ = pruningRadius;
            }

            double getPruningRadius() const
            {
                return pruningRadius_;
            }

            template <template <typename T> class NN>
            void setNearestNeighbors()
            {
                if (nn_ && nn_->size() != 0)
                    OMPL_WARN("Calling setNearestNeighbors will clear all states.");
                clear();
                nn_ = std::make_shared<NN<Motion *>>();
                witnesses_ = std::make_shared<NN<Motion *>>();
                setup();
            }

        protected:
            class Motion
            {
            public:
                Motion() = default;

                Motion(const base::SpaceInformationPtr &si)
                  : state_(si->allocState())
                {
                }

                virtual ~Motion() = default;

                virtual base::State *getState() const
                {
                    return state_;
                }
                virtual Motion *getParent() const
                {
                    return parent_;
                }
                base::Cost accCost_{0.};

                base::State *state_{nullptr};

                Motion *parent_{nullptr};

                unsigned numChildren_{0};

                bool inactive_{false};
            };

            class Witness : public Motion
            {
            public:
                Witness() = default;

                Witness(const base::SpaceInformationPtr &si) : Motion(si)
                {
                }
                base::State *getState() const override
                {
                    return rep_->state_;
                }
                Motion *getParent() const override
                {
                    return rep_->parent_;
                }

                void linkRep(Motion *lRep)
                {
                    rep_ = lRep;
                }

                Motion *rep_{nullptr};
            };

            Motion *selectNode(Motion *sample);

            Witness *findClosestWitness(Motion *node);

            base::State *monteCarloProp(Motion *m);

            void freeMemory();

            double distanceFunction(const Motion *a, const Motion *b) const
            {
                return si_->distance(a->state_, b->state_);
            }

            base::StateSamplerPtr sampler_;

            std::shared_ptr<NearestNeighbors<Motion *>> nn_;

            std::shared_ptr<NearestNeighbors<Motion *>> witnesses_;

            double goalBias_{.05};

            double maxDistance_{5.};

            double selectionRadius_{5.};

            double pruningRadius_{3.};

            RNG rng_;

            std::vector<base::State *> prevSolution_;

            base::Cost prevSolutionCost_;

            base::OptimizationObjectivePtr opt_;
        };
    }
}

#endif