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