SST.h

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/* Authors: Zakary Littlefield */
 
#ifndef OMPL_CONTROL_PLANNERS_SST_SST_
#define OMPL_CONTROL_PLANNERS_SST_SST_
 
#include "ompl/control/planners/PlannerIncludes.h"
#include "ompl/datastructures/NearestNeighbors.h"
 
namespace ompl
{
    namespace control
    {
        class SST : public base::Planner
        {
        public:
            SST(const 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 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 SpaceInformation *si) : state_(si->allocState()), control_(si->allocControl())
                {
                }
 
                virtual ~Motion() = default;
 
                virtual base::State *getState() const
                {
                    return state_;
                }
                virtual Motion *getParent() const
                {
                    return parent_;
                }
 
                base::Cost accCost_{0};

                base::State *state_{nullptr};

                Control *control_{nullptr};

                unsigned int steps_{0};

                Motion *parent_{nullptr};

                unsigned numChildren_{0};

                bool inactive_{false};
            };
 
            class Witness : public Motion
            {
            public:
                Witness() = default;
 
                Witness(const SpaceInformation *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);

            void freeMemory();

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

            base::StateSamplerPtr sampler_;

            ControlSamplerPtr controlSampler_;

            const SpaceInformation *siC_;

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

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

            double goalBias_{0.05};

            double selectionRadius_{0.2};

            double pruningRadius_{0.1};

            RNG rng_;

            std::vector<base::State *> prevSolution_;
            std::vector<Control *> prevSolutionControls_;
            std::vector<unsigned> prevSolutionSteps_;

            base::Cost prevSolutionCost_;

            base::OptimizationObjectivePtr opt_;
        };
    }  // namespace control
}  // namespace ompl
 
#endif