BLITstar.h

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/*********************************************************************
 * Attribution Notice:
 *
 * This file contains code partially adapted from the AIT* and BIT* planners
 * in the Open Motion Planning Library (OMPL). Elements such as sampling
 * structure and queue management are based on those planners.
 *
 * The overall planning strategy and key contributions for BLIT* were developed
 * independently by Yi Wang.
 *********************************************************************/
 
// Authors: Yi Wang, Eyal Weiss, Bingxian Mu, Oren Salzman
 
#ifndef OMPL_GEOMETRIC_PLANNERS_INFORMEDTREES_BLITSTAR_
#define OMPL_GEOMETRIC_PLANNERS_INFORMEDTREES_BLITSTAR_
 
#include <algorithm>
#include <memory>
#include <unordered_map>
#include "ompl/base/Planner.h"
#include <unsupported/Eigen/Polynomials>
#include "ompl/geometric/PathGeometric.h"
#include "ompl/geometric/planners/lazyinformedtrees/blitstar/ImplicitGraph.h"
#include "ompl/geometric/planners/lazyinformedtrees/blitstar/Vertex.h"
#include "ompl/geometric/planners/lazyinformedtrees/blitstar/Queuetypes.h"
 
#include <chrono>
using namespace std::chrono;
namespace ompl
{
    namespace geometric
    {
 
        class BLITstar : public ompl::base::Planner
        {
        public:
            explicit BLITstar(const ompl::base::SpaceInformationPtr &spaceInformation);

            ~BLITstar();

            void setup() override;

            ompl::base::PlannerStatus::StatusType ensureSetup();

            ompl::base::PlannerStatus::StatusType
            ensureStartAndGoalStates(const ompl::base::PlannerTerminationCondition &terminationCondition);

            void clear() override;

            ompl::base::PlannerStatus
            solve(const ompl::base::PlannerTerminationCondition &terminationCondition) override;

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

            void setBatchSize(std::size_t batchSize);

            std::size_t getBatchSize() const;

            void setRewireFactor(double rewireFactor);

            double getRewireFactor() const;

            void enablePruning(bool prune);

            bool isPruningEnabled() const;

            void setUseKNearest(bool useKNearest);

            bool getUseKNearest() const;

            void setMaxNumberOfGoals(unsigned int numberOfGoals);

            unsigned int getMaxNumberOfGoals() const;


            bool SCD(const blitstar::keyEdgePair &edge);
            bool CCD(const blitstar::keyEdgePair &edge);

            void clearReverseVertexQueue();
            void clearForwardVertexQueue();

            void resetReverseValue(const std::shared_ptr<blitstar::Vertex> &vertex);
            void resetForwardValue(const std::shared_ptr<blitstar::Vertex> &vertex);

            bool terminateSearch();

            void insertGoalVerticesInReverseVertexQueue();
            void insertStartVerticesInForWardVertexQueue();

            bool SelectExpandState(bool &forward);

            void resetForwardParentInformation(const std::shared_ptr<blitstar::Vertex> &vertex);
            void resetReverseParentInformation(const std::shared_ptr<blitstar::Vertex> &vertex);
            void resetForwardParentAndRemeberTheVertex(const std::shared_ptr<blitstar::Vertex> &child,
                                                       const std::shared_ptr<blitstar::Vertex> &parent);
            void resetReverseParentAndRemeberTheVertex(const std::shared_ptr<blitstar::Vertex> &child,
                                                       const std::shared_ptr<blitstar::Vertex> &parent);

            void lookingForBestNeighbor(ompl::base::Cost curMin_, size_t neighbor);
            void bestNeighbor(ompl::base::Cost costToCome, ompl::base::Cost costToGoal, size_t neighbor);

            void ForwardLazySearch(const std::shared_ptr<blitstar::Vertex> &vertex);
            void ReverseLazySearch(const std::shared_ptr<blitstar::Vertex> &vertex);

            bool PathValidity(std::shared_ptr<blitstar::Vertex> &vertex);
            void ForwardPathValidityChecking(std::shared_ptr<blitstar::Vertex> &vertex, bool &validity);
            void ReversePathValidityChecking(std::shared_ptr<blitstar::Vertex> &vertex, bool &validity);

            bool isValidAtResolution(const blitstar::keyEdgePair &edge, std::size_t numChecks, bool sparseCheck);

            void EvaluateValidityStartAndToGoal(const std::shared_ptr<blitstar::Vertex> &start,
                                                const std::shared_ptr<blitstar::Vertex> &goal);

            void insertOrUpdateInForwardVertexQueue(const std::shared_ptr<blitstar::Vertex> &vertex,
                                                    ompl::base::Cost CostToCome, ompl::base::Cost CostToGoal,
                                                    bool couldMeet);
            void insertOrUpdateInReverseVertexQueue(const std::shared_ptr<blitstar::Vertex> &vertex,
                                                    ompl::base::Cost CostToCome, ompl::base::Cost CostToGoal,
                                                    bool couldMeet);

            void updateReverseCost(const std::shared_ptr<blitstar::Vertex> &vertex, ompl::base::Cost costToCome,
                                   ompl::base::Cost &costToGo);
            void updateForwardCost(const std::shared_ptr<blitstar::Vertex> &vertex, ompl::base::Cost costToCome,
                                   ompl::base::Cost &costToGo);
            void updateCostToGo(ompl::base::Cost &costToCome, ompl::base::Cost &costToGo,
                                ompl::base::Cost costFromOriginal, bool meetOnTree);

            void updateBestSolutionFoundSoFar(const std::shared_ptr<blitstar::Vertex> &vertex,
                                              ompl::base::Cost meetCost, ompl::base::Cost costToCome,
                                              ompl::base::Cost &costToGo, ompl::base::Cost costFromOri);
 
        private:
            void iterate(const ompl::base::PlannerTerminationCondition &terminationCondition);
            ompl::base::SpaceInformationPtr spaceInformation_;
 
            ompl::base::State *detectionState_;

            void informAboutNewSolution() const;
            void informAboutPlannerStatus(ompl::base::PlannerStatus::StatusType status) const;

            void insertGoalVerticesInReverseQueue();

            std::shared_ptr<ompl::geometric::PathGeometric>
            getPathToVertex(const std::shared_ptr<blitstar::Vertex> &vertex) const;

            std::array<ompl::base::Cost, 3u> computeEstimatedPathCosts(ompl::base::Cost CostToStart,
                                                                       ompl::base::Cost CostToGoal,
                                                                       ompl::base::Cost motionCost) const;
 
            std::array<ompl::base::Cost, 3u> computeSortKey(const std::shared_ptr<blitstar::Vertex> &parent,
                                                            const std::shared_ptr<blitstar::Vertex> &child) const;

            std::array<ompl::base::Cost, 2u> computeSortKey(const std::shared_ptr<blitstar::Vertex> &vertex) const;
 
            std::array<ompl::base::Cost, 2u> computeEstimatedPathCosts(ompl::base::Cost CostToStart,
                                                                       ompl::base::Cost CostToGoal) const;

            void updateExactSolution();

            ompl::base::PlannerStatus::StatusType updateSolution();

            ompl::base::PlannerStatus::StatusType updateSolution(const std::shared_ptr<blitstar::Vertex> &vertex);

            ompl::base::Cost lowerboundToStart(const std::shared_ptr<blitstar::Vertex> &vertex) const;
            ompl::base::Cost lowerboundToGoal(const std::shared_ptr<blitstar::Vertex> &vertex) const;

            std::size_t countNumVerticesInForwardTree() const;

            std::size_t countNumVerticesInReverseTree() const;

            ompl::base::Cost solutionCost_;

            ompl::base::Cost PriorityC;

            ompl::base::Cost C_curr;

            ompl::base::Cost approximateSolutionCost_{};

            ompl::base::Cost approximateSolutionCostToGoal_{};

            ompl::base::Cost fmin_{0u};

            ompl::base::Cost ForwardCost{0u};
            ompl::base::Cost ReverseCost{0u};
 
            ompl::base::Cost minimalneighbor_{0u};
            blitstar::ImplicitGraph graph_;

            blitstar::VertexQueue forwardVertexQueue_;
            blitstar::VertexQueue reverseVertexQueue_;

            std::shared_ptr<blitstar::Vertex> BestVertex_;

            std::shared_ptr<ompl::geometric::PathGeometric> path_;

            blitstar::MiddleVertex V_meet;

            bool isVertexBetter(const blitstar::KeyVertexPair &lhs, const blitstar::KeyVertexPair &rhs) const;

            std::size_t numIterations_{0u};
            std::size_t bestNeighbor_{0u};
            std::size_t numSparseCollisionChecksCurrentLevel_{0u};

            std::size_t forwardId_{0u};
            std::size_t reverseId_{0u};
 
            std::size_t meetId_{0u};
            std::size_t batchSize_{100u};

            bool trackApproximateSolutions_{true};

            bool isPruningEnabled_{false};
            bool increProcess_{false};
 
            bool meeting_{false};
            bool start_scratch_{false};
 
            bool betterThan(const ompl::base::Cost &cost1, const ompl::base::Cost &cost2);
            bool largerThan(const ompl::base::Cost &cost1, const ompl::base::Cost &cost2);

            bool NeedMoreSamples();
            bool iSolution_{false};
            bool need_Prune_{false};
            bool isVertexEmpty_{true};
            bool found_meeting_{false};
            bool find_solution_{false};
            bool forwardInvalid_{false};
            bool reverseInvalid_{false};
            bool goalCloseToStart_{false};
            bool searchExhausted_{false};
 
            double time_taken{0u};
            ompl::base::OptimizationObjectivePtr objective_;

            ompl::base::MotionValidatorPtr motionValidator_;

            std::size_t numProcessedEdges_{0u};
            std::size_t numbatch_{0u};
            std::shared_ptr<ompl::base::StateSpace> space_;
            std::size_t numEdgeCollisionChecks_{0u};

            mutable unsigned int numCollisionCheckedEdges_{0u};
        };
    }  // namespace geometric
}  // namespace ompl
 
#endif  // OMPL_GEOMETRIC_PLANNERS_INFORMEDTREES_bmitstar