BKPIECE1.cpp

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/* Author: Ioan Sucan */
 
#include "ompl/geometric/planners/kpiece/BKPIECE1.h"
#include "ompl/base/goals/GoalSampleableRegion.h"
#include "ompl/tools/config/SelfConfig.h"
#include <cassert>
 
ompl::geometric::BKPIECE1::BKPIECE1(const base::SpaceInformationPtr &si)
  : base::Planner(si, "BKPIECE1")
  , dStart_([this](Motion *m) { freeMotion(m); })
  , dGoal_([this](Motion *m) { freeMotion(m); })
{
    specs_.recognizedGoal = base::GOAL_SAMPLEABLE_REGION;
 
    Planner::declareParam<double>("range", this, &BKPIECE1::setRange, &BKPIECE1::getRange, "0.:1.:10000.");
    Planner::declareParam<double>("border_fraction", this, &BKPIECE1::setBorderFraction, &BKPIECE1::getBorderFraction,
                                  "0.:.05:1.");
    Planner::declareParam<double>("failed_expansion_score_factor", this, &BKPIECE1::setFailedExpansionCellScoreFactor,
                                  &BKPIECE1::getFailedExpansionCellScoreFactor);
    Planner::declareParam<double>("min_valid_path_fraction", this, &BKPIECE1::setMinValidPathFraction,
                                  &BKPIECE1::getMinValidPathFraction);
}
 
ompl::geometric::BKPIECE1::~BKPIECE1() = default;
 
void ompl::geometric::BKPIECE1::setup()
{
    Planner::setup();
    tools::SelfConfig sc(si_, getName());
    sc.configureProjectionEvaluator(projectionEvaluator_);
    sc.configurePlannerRange(maxDistance_);
 
    if (failedExpansionScoreFactor_ < std::numeric_limits<double>::epsilon() || failedExpansionScoreFactor_ > 1.0)
        throw Exception("Failed expansion cell score factor must be in the range (0,1]");
    if (minValidPathFraction_ < std::numeric_limits<double>::epsilon() || minValidPathFraction_ > 1.0)
        throw Exception("The minimum valid path fraction must be in the range (0,1]");
 
    dStart_.setDimension(projectionEvaluator_->getDimension());
    dGoal_.setDimension(projectionEvaluator_->getDimension());
}
 
ompl::base::PlannerStatus ompl::geometric::BKPIECE1::solve(const base::PlannerTerminationCondition &ptc)
{
    checkValidity();
    auto *goal = dynamic_cast<base::GoalSampleableRegion *>(pdef_->getGoal().get());
 
    if (goal == nullptr)
    {
        OMPL_ERROR("%s: Unknown type of goal", getName().c_str());
        return base::PlannerStatus::UNRECOGNIZED_GOAL_TYPE;
    }
 
    Discretization<Motion>::Coord xcoord(projectionEvaluator_->getDimension());
 
    while (const base::State *st = pis_.nextStart())
    {
        auto *motion = new Motion(si_);
        si_->copyState(motion->state, st);
        motion->root = motion->state;
        projectionEvaluator_->computeCoordinates(motion->state, xcoord);
        dStart_.addMotion(motion, xcoord);
    }
 
    if (dStart_.getMotionCount() == 0)
    {
        OMPL_ERROR("%s: Motion planning start tree could not be initialized!", getName().c_str());
        return base::PlannerStatus::INVALID_START;
    }
 
    if (!goal->couldSample())
    {
        OMPL_ERROR("%s: Insufficient states in sampleable goal region", getName().c_str());
        return base::PlannerStatus::INVALID_GOAL;
    }
 
    if (!sampler_)
        sampler_ = si_->allocValidStateSampler();
 
    OMPL_INFORM("%s: Starting planning with %d states already in datastructure", getName().c_str(),
                (int)(dStart_.getMotionCount() + dGoal_.getMotionCount()));
 
    std::vector<Motion *> solution;
    base::State *xstate = si_->allocState();
    bool startTree = true;
    bool solved = false;
 
    while (!ptc)
    {
        Discretization<Motion> &disc = startTree ? dStart_ : dGoal_;
        startTree = !startTree;
        Discretization<Motion> &otherDisc = startTree ? dStart_ : dGoal_;
        disc.countIteration();
 
        // if we have not sampled too many goals already
        if (dGoal_.getMotionCount() == 0 || pis_.getSampledGoalsCount() < dGoal_.getMotionCount() / 2)
        {
            const base::State *st = dGoal_.getMotionCount() == 0 ? pis_.nextGoal(ptc) : pis_.nextGoal();
            if (st != nullptr)
            {
                auto *motion = new Motion(si_);
                si_->copyState(motion->state, st);
                motion->root = motion->state;
                projectionEvaluator_->computeCoordinates(motion->state, xcoord);
                dGoal_.addMotion(motion, xcoord);
            }
            if (dGoal_.getMotionCount() == 0)
            {
                OMPL_ERROR("%s: Unable to sample any valid states for goal tree", getName().c_str());
                break;
            }
        }
 
        Discretization<Motion>::Cell *ecell = nullptr;
        Motion *existing = nullptr;
        disc.selectMotion(existing, ecell);
        assert(existing);
        if (sampler_->sampleNear(xstate, existing->state, maxDistance_))
        {
            std::pair<base::State *, double> fail(xstate, 0.0);
            bool keep = si_->checkMotion(existing->state, xstate, fail);
            if (!keep && fail.second > minValidPathFraction_)
                keep = true;
 
            if (keep)
            {
                /* create a motion */
                auto *motion = new Motion(si_);
                si_->copyState(motion->state, xstate);
                motion->root = existing->root;
                motion->parent = existing;
 
                projectionEvaluator_->computeCoordinates(motion->state, xcoord);
                disc.addMotion(motion, xcoord);
 
                Discretization<Motion>::Cell *cellC = otherDisc.getGrid().getCell(xcoord);
 
                if ((cellC != nullptr) && !cellC->data->motions.empty())
                {
                    Motion *connectOther = cellC->data->motions[rng_.uniformInt(0, cellC->data->motions.size() - 1)];
 
                    if (goal->isStartGoalPairValid(startTree ? connectOther->root : motion->root,
                                                   startTree ? motion->root : connectOther->root) &&
                        si_->checkMotion(motion->state, connectOther->state))
                    {
                        if (startTree)
                            connectionPoint_ = std::make_pair(connectOther->state, motion->state);
                        else
                            connectionPoint_ = std::make_pair(motion->state, connectOther->state);
 
                        /* extract the motions and put them in solution vector */
 
                        std::vector<Motion *> mpath1;
                        while (motion != nullptr)
                        {
                            mpath1.push_back(motion);
                            motion = motion->parent;
                        }
 
                        std::vector<Motion *> mpath2;
                        while (connectOther != nullptr)
                        {
                            mpath2.push_back(connectOther);
                            connectOther = connectOther->parent;
                        }
 
                        if (startTree)
                            mpath1.swap(mpath2);
 
                        auto path(std::make_shared<PathGeometric>(si_));
                        path->getStates().reserve(mpath1.size() + mpath2.size());
                        for (int i = mpath1.size() - 1; i >= 0; --i)
                            path->append(mpath1[i]->state);
                        for (auto &i : mpath2)
                            path->append(i->state);
 
                        pdef_->addSolutionPath(path, false, 0.0, getName());
                        solved = true;
                        break;
                    }
                }
            }
            else
                ecell->data->score *= failedExpansionScoreFactor_;
        }
        else
            ecell->data->score *= failedExpansionScoreFactor_;
        disc.updateCell(ecell);
    }
 
    si_->freeState(xstate);
 
    OMPL_INFORM("%s: Created %u (%u start + %u goal) states in %u cells (%u start (%u on boundary) + %u goal (%u on "
                "boundary))",
                getName().c_str(), dStart_.getMotionCount() + dGoal_.getMotionCount(), dStart_.getMotionCount(),
                dGoal_.getMotionCount(), dStart_.getCellCount() + dGoal_.getCellCount(), dStart_.getCellCount(),
                dStart_.getGrid().countExternal(), dGoal_.getCellCount(), dGoal_.getGrid().countExternal());
 
    return solved ? base::PlannerStatus::EXACT_SOLUTION : base::PlannerStatus::TIMEOUT;
}
 
void ompl::geometric::BKPIECE1::freeMotion(Motion *motion)
{
    if (motion->state != nullptr)
        si_->freeState(motion->state);
    delete motion;
}
 
void ompl::geometric::BKPIECE1::clear()
{
    Planner::clear();
 
    sampler_.reset();
    dStart_.clear();
    dGoal_.clear();
    connectionPoint_ = std::make_pair<base::State *, base::State *>(nullptr, nullptr);
}
 
void ompl::geometric::BKPIECE1::getPlannerData(base::PlannerData &data) const
{
    Planner::getPlannerData(data);
    dStart_.getPlannerData(data, 1, true, nullptr);
    dGoal_.getPlannerData(data, 2, false, nullptr);
 
    // Insert the edge connecting the two trees
    data.addEdge(data.vertexIndex(connectionPoint_.first), data.vertexIndex(connectionPoint_.second));
}