src/rrts.cc

   1 #include <algorithm>
   2 #include "rrts.h"
   3
   4 #include "reeds_shepp.h"
   5
   6 #define ETA 1.0 // for steer, nv
   7 #define GAMMA(cV) ({ \
   8         __typeof__ (cV) _cV = (cV); \
   9         pow(log(_cV) / _cV, 1.0 / 3.0); \
  10 })
  11
  12 template <typename T> int sgn(T val) {
  13         return (T(0) < val) - (val < T(0));
  14 }
  15
  16 RRTNode::RRTNode()
  17 {
  18 }
  19
  20 RRTNode::RRTNode(const BicycleCar &bc) : BicycleCar(bc)
  21 {
  22 }
  23
  24 Obstacle::Obstacle()
  25 {
  26 }
  27
  28 double RRTS::elapsed()
  29 {
  30         std::chrono::duration<double> dt;
  31         dt = std::chrono::duration_cast<std::chrono::duration<double>>(
  32                 std::chrono::high_resolution_clock::now()
  33                 - this->tstart_
  34         );
  35         this->scnt_ = dt.count();
  36         return this->scnt_;
  37 }
  38
  39 bool RRTS::should_stop()
  40 {
  41         // the following counters must be updated, do not comment
  42         this->icnt_++;
  43         this->elapsed();
  44         // decide the stop conditions (maybe comment some lines)
  45         if (this->icnt_ > 999) return true;
  46         if (this->scnt_ > 10) return true;
  47         if (this->gf()) return true;
  48         // but continue by default
  49         return false;
  50 }
  51
  52 void RRTS::store_node(RRTNode n)
  53 {
  54         this->nodes().push_back(n);
  55 }
  56
  57 // RRT procedures
  58 std::tuple<bool, unsigned int, unsigned int>
  59 RRTS::collide(std::vector<std::tuple<double, double>> &poly)
  60 {
  61         for (auto &o: this->obstacles())
  62                 if (std::get<0>(::collide(poly, o.poly())))
  63                         return ::collide(poly, o.poly());
  64         return std::make_tuple(false, 0, 0);
  65 }
  66
  67 std::tuple<bool, unsigned int, unsigned int>
  68 RRTS::collide_steered_from(RRTNode &f)
  69 {
  70         std::vector<std::tuple<double, double>> s;
  71         s.push_back(std::make_tuple(f.x(), f.y()));
  72         for (auto &n: this->steered()) {
  73                 s.push_back(std::make_tuple(n.lfx(), n.lfy()));
  74                 s.push_back(std::make_tuple(n.lrx(), n.lry()));
  75                 s.push_back(std::make_tuple(n.rrx(), n.rry()));
  76                 s.push_back(std::make_tuple(n.rfx(), n.rfy()));
  77         }
  78         auto col = this->collide(s);
  79         auto strip_from = this->steered().size() - std::get<1>(col) / 4;
  80         if (std::get<0>(col) && strip_from > 0) {
  81                 while (strip_from-- > 0) {
  82                         this->steered().pop_back();
  83                 }
  84                 return this->collide_steered_from(f);
  85         }
  86         return col;
  87 }
  88
  89 std::tuple<bool, unsigned int, unsigned int>
  90 RRTS::collide_two_nodes(RRTNode &f, RRTNode &t)
  91 {
  92         std::vector<std::tuple<double, double>> p;
  93         p.push_back(std::make_tuple(f.lfx(), f.lfy()));
  94         p.push_back(std::make_tuple(f.lrx(), f.lry()));
  95         p.push_back(std::make_tuple(f.rrx(), f.rry()));
  96         p.push_back(std::make_tuple(f.rfx(), f.rfy()));
  97         p.push_back(std::make_tuple(t.lfx(), t.lfy()));
  98         p.push_back(std::make_tuple(t.lrx(), t.lry()));
  99         p.push_back(std::make_tuple(t.rrx(), t.rry()));
 100         p.push_back(std::make_tuple(t.rfx(), t.rfy()));
 101         return this->collide(p);
 102 }
 103
 104 double RRTS::cost_build(RRTNode &f, RRTNode &t)
 105 {
 106         double cost = 0;
 107         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
 108         return cost;
 109 }
 110
 111 double RRTS::cost_search(RRTNode &f, RRTNode &t)
 112 {
 113         double cost = 0;
 114         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
 115         return cost;
 116 }
 117
 118 void RRTS::sample()
 119 {
 120         double x = this->ndx_(this->gen_);
 121         double y = this->ndy_(this->gen_);
 122         double h = this->ndh_(this->gen_);
 123         this->samples().push_back(RRTNode());
 124         this->samples().back().x(x);
 125         this->samples().back().y(y);
 126         this->samples().back().h(h);
 127 }
 128
 129 RRTNode *RRTS::nn(RRTNode &t)
 130 {
 131         RRTNode *nn = &this->nodes().front();
 132         double cost = this->cost_search(*nn, t);
 133         for (auto &f: this->nodes()) {
 134                 if (this->cost_search(f, t) < cost) {
 135                         nn = &f;
 136                         cost = this->cost_search(f, t);
 137                 }
 138         }
 139         return nn;
 140 }
 141
 142 std::vector<RRTNode *> RRTS::nv(RRTNode &t)
 143 {
 144         std::vector<RRTNode *> nv;
 145         double cost = std::min(GAMMA(this->nodes().size()), ETA);
 146         for (auto &f: this->nodes())
 147                 if (this->cost_search(f, t) < cost)
 148                         nv.push_back(&f);
 149         return nv;
 150 }
 151
 152 int cb_rs_steer(double q[4], void *user_data)
 153 {
 154         std::vector<RRTNode> *nodes = (std::vector<RRTNode> *) user_data;
 155         RRTNode *ln = nullptr;
 156         if (nodes->size() > 0)
 157                 ln = &nodes->back();
 158         nodes->push_back(RRTNode());
 159         nodes->back().x(q[0]);
 160         nodes->back().y(q[1]);
 161         nodes->back().h(q[2]);
 162         nodes->back().sp(q[3]);
 163         if (nodes->back().sp() == 0)
 164                 nodes->back().set_t(RRTNodeType::cusp);
 165         else if (ln != nullptr && sgn(ln->sp()) != sgn(nodes->back().sp()))
 166                 ln->set_t(RRTNodeType::cusp);
 167         return 0;
 168 }
 169
 170 void RRTS::steer(RRTNode &f, RRTNode &t)
 171 {
 172         this->steered().clear();
 173         double q0[] = {f.x(), f.y(), f.h()};
 174         double q1[] = {t.x(), t.y(), t.h()};
 175         ReedsSheppStateSpace rsss(f.mtr());
 176         rsss.sample(q0, q1, 0.5, cb_rs_steer, &this->steered());
 177 }
 178
 179 void RRTS::join_steered(RRTNode *f)
 180 {
 181         while (this->steered().size() > 0) {
 182                 this->store_node(this->steered().front());
 183                 RRTNode *t = &this->nodes().back();
 184                 t->p(f);
 185                 t->c(this->cost_build(*f, *t));
 186                 this->steered().erase(this->steered().begin());
 187                 f = t;
 188         }
 189 }
 190
 191 bool RRTS::goal_found(RRTNode &f)
 192 {
 193         bool found = false;
 194         for (auto &g: this->goals()) {
 195                 double cost = this->cost_build(f, g);
 196                 double edist = sqrt(
 197                         pow(f.x() - g.x(), 2)
 198                         + pow(f.y() - g.y(), 2)
 199                 );
 200                 double adist = std::abs(f.h() - g.h());
 201                 if (edist < 0.05 && adist < M_PI / 32) {
 202                         found = true;
 203                         if (g.p() == nullptr || cc(f) + cost < cc(g)) {
 204                                 g.p(&f);
 205                                 g.c(cost);
 206                         }
 207                 }
 208         }
 209         return found;
 210 }
 211
 212 // RRT* procedures
 213 bool RRTS::connect()
 214 {
 215         RRTNode *t = &this->steered().front();
 216         RRTNode *f = this->nn(this->samples().back());
 217         double cost = this->cost_search(*f, *t);
 218         for (auto n: this->nv(*t)) {
 219                 if (
 220                         !std::get<0>(this->collide_two_nodes(*n, *t))
 221                         && this->cost_search(*n, *t) < cost
 222                 ) {
 223                         f = n;
 224                         cost = this->cost_search(*n, *t);
 225                 }
 226         }
 227         this->store_node(this->steered().front());
 228         t = &this->nodes().back();
 229         t->p(f);
 230         t->c(this->cost_build(*f, *t));
 231         t->set_t(RRTNodeType::connected);
 232         return true;
 233 }
 234
 235 void RRTS::rewire()
 236 {
 237         RRTNode *f = &this->nodes().back();
 238         for (auto n: this->nv(*f)) {
 239                 if (
 240                         !std::get<0>(this->collide_two_nodes(*f, *n))
 241                         && cc(*f) + this->cost_search(*f, *n) < cc(*n)
 242                 ) {
 243                         n->p(f);
 244                         n->c(this->cost_build(*f, *n));
 245                 }
 246         }
 247 }
 248
 249 // API
 250 void RRTS::init()
 251 {
 252 }
 253
 254 void RRTS::deinit()
 255 {
 256 }
 257
 258 std::vector<RRTNode *> RRTS::path()
 259 {
 260         std::vector<RRTNode *> path;
 261         if (this->goals().size() == 0)
 262                 return path;
 263         RRTNode *goal = &this->goals().front();
 264         for (auto &n: this->goals()) {
 265                 if (
 266                         n.p() != nullptr
 267                         && (n.c() < goal->c() || goal->p() == nullptr)
 268                 ) {
 269                         goal = &n;
 270                 }
 271         }
 272         if (goal->p() == nullptr)
 273                 return path;
 274         while (goal != nullptr) {
 275                 path.push_back(goal);
 276                 goal = goal->p();
 277         }
 278         std::reverse(path.begin(), path.end());
 279         return path;
 280 }
 281
 282 bool RRTS::next()
 283 {
 284         if (this->icnt_ == 0)
 285                 this->tstart_ = std::chrono::high_resolution_clock::now();
 286         bool next = true;
 287         if (this->should_stop())
 288                 return false;
 289         this->sample();
 290         this->steer(
 291                 *this->nn(this->samples().back()),
 292                 this->samples().back()
 293         );
 294         if (std::get<0>(this->collide_steered_from(
 295                 *this->nn(this->samples().back())
 296         )))
 297                 return next;
 298         if (!this->connect())
 299                 return next;
 300         this->rewire();
 301         unsigned scnt = this->steered().size();
 302         this->steered().erase(this->steered().begin());
 303         this->join_steered(&this->nodes().back());
 304         RRTNode *just_added = &this->nodes().back();
 305         while (scnt > 0) {
 306                 scnt--;
 307                 for (auto &g: this->goals()) {
 308                         this->steer(*just_added, g);
 309                         if (std::get<0>(this->collide_steered_from(
 310                                 *just_added
 311                         )))
 312                                 continue;
 313                         this->join_steered(just_added);
 314                 }
 315                 this->gf(this->goal_found(this->nodes().back()));
 316                 just_added = just_added->p();
 317         }
 318         return next;
 319 }
 320
 321 void RRTS::set_sample(
 322         double mx, double dx,
 323         double my, double dy,
 324         double mh, double dh
 325 )
 326 {
 327         this->ndx_ = std::normal_distribution<double>(mx, dx);
 328         this->ndy_ = std::normal_distribution<double>(my, dy);
 329         this->ndh_ = std::normal_distribution<double>(mh, dh);
 330 }
 331
 332 RRTS::RRTS()
 333         : gen_(std::random_device{}())
 334 {
 335         this->goals().reserve(100);
 336         this->nodes().reserve(4000000);
 337         this->samples().reserve(1000);
 338         this->steered().reserve(20000);
 339         this->store_node(RRTNode()); // root
 340 }
 341
 342 double cc(RRTNode &t)
 343 {
 344         RRTNode *n = &t;
 345         double cost = 0;
 346         while (n != nullptr) {
 347                 cost += n->c();
 348                 n = n->p();
 349         }
 350         return cost;
 351 }