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EST.cpp
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00034 
00035 /* Author: Ioan Sucan */
00036 
00037 #include "ompl/geometric/planners/est/EST.h"
00038 #include "ompl/base/GoalSampleableRegion.h"
00039 #include "ompl/tools/config/SelfConfig.h"
00040 #include <limits>
00041 #include <cassert>
00042 
00043 ompl::geometric::EST::EST(const base::SpaceInformationPtr &si) : base::Planner(si, "EST")
00044 {
00045     specs_.approximateSolutions = true;
00046     goalBias_ = 0.05;
00047     maxDistance_ = 0.0;
00048 
00049     Planner::declareParam<double>("range", this, &EST::setRange, &EST::getRange);
00050     Planner::declareParam<double>("goal_bias", this, &EST::setGoalBias, &EST::getGoalBias);
00051 }
00052 
00053 ompl::geometric::EST::~EST(void)
00054 {
00055     freeMemory();
00056 }
00057 
00058 void ompl::geometric::EST::setup(void)
00059 {
00060     Planner::setup();
00061     tools::SelfConfig sc(si_, getName());
00062     sc.configureProjectionEvaluator(projectionEvaluator_);
00063     sc.configurePlannerRange(maxDistance_);
00064 
00065     tree_.grid.setDimension(projectionEvaluator_->getDimension());
00066 }
00067 
00068 void ompl::geometric::EST::clear(void)
00069 {
00070     Planner::clear();
00071     sampler_.reset();
00072     freeMemory();
00073     tree_.grid.clear();
00074     tree_.size = 0;
00075     pdf_.clear();
00076 }
00077 
00078 void ompl::geometric::EST::freeMemory(void)
00079 {
00080     for (Grid<MotionInfo>::iterator it = tree_.grid.begin(); it != tree_.grid.end() ; ++it)
00081     {
00082         for (unsigned int i = 0 ; i < it->second->data.size() ; ++i)
00083         {
00084             if (it->second->data[i]->state)
00085                 si_->freeState(it->second->data[i]->state);
00086             delete it->second->data[i];
00087         }
00088     }
00089 }
00090 
00091 bool ompl::geometric::EST::solve(const base::PlannerTerminationCondition &ptc)
00092 {
00093     checkValidity();
00094     base::Goal                   *goal = pdef_->getGoal().get();
00095     base::GoalSampleableRegion *goal_s = dynamic_cast<base::GoalSampleableRegion*>(goal);
00096 
00097     while (const base::State *st = pis_.nextStart())
00098     {
00099         Motion *motion = new Motion(si_);
00100         si_->copyState(motion->state, st);
00101         addMotion(motion);
00102     }
00103 
00104     if (tree_.grid.size() == 0)
00105     {
00106         msg_.error("There are no valid initial states!");
00107         return false;
00108     }
00109 
00110     if (!sampler_)
00111         sampler_ = si_->allocValidStateSampler();
00112 
00113     msg_.inform("Starting with %u states", tree_.size);
00114 
00115     Motion *solution  = NULL;
00116     Motion *approxsol = NULL;
00117     double  approxdif = std::numeric_limits<double>::infinity();
00118     base::State *xstate = si_->allocState();
00119 
00120     while (ptc() == false)
00121     {
00122         /* Decide on a state to expand from */
00123         Motion *existing = selectMotion();
00124         assert(existing);
00125 
00126         /* sample random state (with goal biasing) */
00127         if (goal_s && rng_.uniform01() < goalBias_ && goal_s->canSample())
00128             goal_s->sampleGoal(xstate);
00129         else
00130             if (!sampler_->sampleNear(xstate, existing->state, maxDistance_))
00131                 continue;
00132 
00133         if (si_->checkMotion(existing->state, xstate))
00134         {
00135             /* create a motion */
00136             Motion *motion = new Motion(si_);
00137             si_->copyState(motion->state, xstate);
00138             motion->parent = existing;
00139 
00140             addMotion(motion);
00141             double dist = 0.0;
00142             bool solved = goal->isSatisfied(motion->state, &dist);
00143             if (solved)
00144             {
00145                 approxdif = dist;
00146                 solution = motion;
00147                 break;
00148             }
00149             if (dist < approxdif)
00150             {
00151                 approxdif = dist;
00152                 approxsol = motion;
00153             }
00154         }
00155     }
00156 
00157     bool solved = false;
00158     bool approximate = false;
00159     if (solution == NULL)
00160     {
00161         solution = approxsol;
00162         approximate = true;
00163     }
00164 
00165     if (solution != NULL)
00166     {
00167         /* construct the solution path */
00168         std::vector<Motion*> mpath;
00169         while (solution != NULL)
00170         {
00171             mpath.push_back(solution);
00172             solution = solution->parent;
00173         }
00174 
00175         /* set the solution path */
00176         PathGeometric *path = new PathGeometric(si_);
00177         for (int i = mpath.size() - 1 ; i >= 0 ; --i)
00178             path->append(mpath[i]->state);
00179         goal->addSolutionPath(base::PathPtr(path), approximate, approxdif);
00180         solved = true;
00181     }
00182 
00183     si_->freeState(xstate);
00184 
00185     msg_.inform("Created %u states in %u cells", tree_.size, tree_.grid.size());
00186 
00187     return solved;
00188 }
00189 
00190 ompl::geometric::EST::Motion* ompl::geometric::EST::selectMotion(void)
00191 {
00192     GridCell* cell = pdf_.sample(rng_.uniform01());
00193     return cell && !cell->data.empty() ? cell->data[rng_.uniformInt(0, cell->data.size() - 1)] : NULL;
00194 }
00195 
00196 void ompl::geometric::EST::addMotion(Motion *motion)
00197 {
00198     Grid<MotionInfo>::Coord coord;
00199     projectionEvaluator_->computeCoordinates(motion->state, coord);
00200     GridCell* cell = tree_.grid.getCell(coord);
00201     if (cell)
00202     {
00203         cell->data.push_back(motion);
00204         pdf_.update(cell->data.elem_, 1.0/cell->data.size());
00205     }
00206     else
00207     {
00208         cell = tree_.grid.createCell(coord);
00209         cell->data.push_back(motion);
00210         tree_.grid.add(cell);
00211         cell->data.elem_ = pdf_.add(cell, 1.0);
00212     }
00213     tree_.size++;
00214 }
00215 
00216 void ompl::geometric::EST::getPlannerData(base::PlannerData &data) const
00217 {
00218     Planner::getPlannerData(data);
00219 
00220     std::vector<MotionInfo> motions;
00221     tree_.grid.getContent(motions);
00222 
00223     for (unsigned int i = 0 ; i < motions.size() ; ++i)
00224         for (unsigned int j = 0 ; j < motions[i].size() ; ++j)
00225             data.recordEdge(motions[i][j]->parent ? motions[i][j]->parent->state : NULL, motions[i][j]->state);
00226 }