constraints_library.cpp

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/* Author: Ioan Sucan */

#include <moveit/ompl_interface/constraints_library.h>
#include <moveit/ompl_interface/detail/constrained_sampler.h>
#include <moveit/profiler/profiler.h>
#include <ompl/tools/config/SelfConfig.h>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/filesystem.hpp>
#include <fstream>

namespace ompl_interface
{

namespace
{
template<typename T>
void msgToHex(const T& msg, std::string &hex)
{
  static const char symbol[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
  const size_t serial_size_arg = ros::serialization::serializationLength(msg);

  boost::shared_array<uint8_t> buffer_arg(new uint8_t[serial_size_arg]);
  ros::serialization::OStream stream_arg(buffer_arg.get(), serial_size_arg);
  ros::serialization::serialize(stream_arg, msg);
  hex.resize(serial_size_arg * 2);
  for (std::size_t i = 0 ; i < serial_size_arg ; ++i)
  {
    hex[i * 2] = symbol[buffer_arg[i]/16];
    hex[i * 2 + 1] = symbol[buffer_arg[i]%16];
  }
}

template<typename T>
void hexToMsg(const std::string &hex, T& msg)
{
  const size_t serial_size_arg = hex.length() / 2;
  boost::shared_array<uint8_t> buffer_arg(new uint8_t[serial_size_arg]);
  for (std::size_t i = 0 ; i < serial_size_arg ; ++i)
  {
    buffer_arg[i] =
      (hex[i * 2] <= '9' ? (hex[i * 2] - '0') : (hex[i * 2] - 'A' + 10)) * 16 +
      (hex[i * 2 + 1] <= '9' ? (hex[i * 2 + 1] - '0') : (hex[i * 2 + 1] - 'A' + 10));
  }
  ros::serialization::IStream stream_arg(buffer_arg.get(), serial_size_arg);
  ros::serialization::deserialize(stream_arg, msg);
}
}

class ConstraintApproximationStateSampler : public ob::StateSampler
{
public:

  ConstraintApproximationStateSampler(const ob::StateSpace *space, const ConstraintApproximationStateStorage *state_storage, std::size_t milestones) :
    ob::StateSampler(space), state_storage_(state_storage)
  {
    max_index_ = milestones - 1;
    inv_dim_ = space->getDimension() > 0 ? 1.0 / (double)space->getDimension() : 1.0;
  }

  virtual void sampleUniform(ob::State *state)
  {
    space_->copyState(state, state_storage_->getState(rng_.uniformInt(0, max_index_)));
  }

  virtual void sampleUniformNear(ob::State *state, const ob::State *near, const double distance)
  {
    int index = -1;
    int tag = near->as<ModelBasedStateSpace::StateType>()->tag;

    if (tag >= 0)
    {
      const ConstrainedStateMetadata &md = state_storage_->getMetadata(tag);
      if (!md.first.empty())
      {
        std::size_t matt = md.first.size() / 3;
        std::size_t att = 0;
        do
        {
          index = md.first[rng_.uniformInt(0, md.first.size() - 1)];
        } while (dirty_.find(index) != dirty_.end() && ++att < matt);
        if (att >= matt)
          index = -1;
        else
          dirty_.insert(index);
      }
    }
    if (index < 0)
      index = rng_.uniformInt(0, max_index_);

    double dist = space_->distance(near, state_storage_->getState(index));

    if (dist > distance)
    {
      double d = pow(rng_.uniform01(), inv_dim_) * distance;
      space_->interpolate(near, state_storage_->getState(index), d / dist, state);
    }
    else
      space_->copyState(state, state_storage_->getState(index));
  }

  virtual void sampleGaussian(ob::State *state, const ob::State *mean, const double stdDev)
  {
    sampleUniformNear(state, mean, rng_.gaussian(0.0, stdDev));
  }

protected:

  const ConstraintApproximationStateStorage *state_storage_;
  std::set<std::size_t> dirty_;
  unsigned int max_index_;
  double inv_dim_;
};

bool interpolateUsingStoredStates(const ConstraintApproximationStateStorage *state_storage, const ob::State *from, const ob::State *to, const double t, ob::State *state)
{
  int tag_from = from->as<ModelBasedStateSpace::StateType>()->tag;
  int tag_to = to->as<ModelBasedStateSpace::StateType>()->tag;

  if (tag_from < 0 || tag_to < 0)
    return false;
  
  if (tag_from == tag_to)
    state_storage->getStateSpace()->copyState(state, to);
  else
  {
    const ConstrainedStateMetadata &md = state_storage->getMetadata(tag_from);
    
    std::map<std::size_t, std::pair<std::size_t, std::size_t> >::const_iterator it = md.second.find(tag_to);
    if (it == md.second.end())
      return false;
    const std::pair<std::size_t, std::size_t> &istates = it->second;
    std::size_t index = (std::size_t)((istates.second - istates.first + 2) * t + 0.5);
    
    if (index == 0)
      state_storage->getStateSpace()->copyState(state, from);
    else
    {
      --index;
      if (index >= istates.second - istates.first)
        state_storage->getStateSpace()->copyState(state, to);
      else
        state_storage->getStateSpace()->copyState(state, state_storage->getState(istates.first + index));
    }
  }
  return true;
}

ompl_interface::InterpolationFunction ompl_interface::ConstraintApproximation::getInterpolationFunction() const
{
  if (explicit_motions_ && milestones_ > 0 && milestones_ < state_storage_->size())
    return boost::bind(&interpolateUsingStoredStates, state_storage_, _1, _2, _3, _4);
  return InterpolationFunction();
}

ompl::base::StateSamplerPtr allocConstraintApproximationStateSampler(const ob::StateSpace *space, const std::vector<int> &expected_signature,
                                                                     const ConstraintApproximationStateStorage *state_storage, std::size_t milestones)
{
  std::vector<int> sig;
  space->computeSignature(sig);
  if (sig != expected_signature)
    return ompl::base::StateSamplerPtr();
  else
    return ompl::base::StateSamplerPtr(new ConstraintApproximationStateSampler(space, state_storage, milestones));
}

}

ompl_interface::ConstraintApproximation::ConstraintApproximation(const std::string &group, const std::string &state_space_parameterization,
                                                                 bool explicit_motions, const moveit_msgs::Constraints &msg, const std::string &filename,
                                                                 const ompl::base::StateStoragePtr &storage, std::size_t milestones) :
  group_(group), state_space_parameterization_(state_space_parameterization), explicit_motions_(explicit_motions), constraint_msg_(msg),
  ompldb_filename_(filename), state_storage_ptr_(storage), milestones_(milestones)
{
  state_storage_ = static_cast<ConstraintApproximationStateStorage*>(state_storage_ptr_.get());
  state_storage_->getStateSpace()->computeSignature(space_signature_);
  if (milestones_ == 0)
    milestones_ = state_storage_->size();
}

ompl::base::StateSamplerAllocator ompl_interface::ConstraintApproximation::getStateSamplerAllocator(const moveit_msgs::Constraints &msg) const
{
  if (state_storage_->size() == 0)
    return ompl::base::StateSamplerAllocator();
  return boost::bind(&allocConstraintApproximationStateSampler, _1, space_signature_, state_storage_, milestones_);
}
/*
void ompl_interface::ConstraintApproximation::visualizeDistribution(const std::string &link_name, unsigned int count, visualization_msgs::MarkerArray &arr) const
{
  robot_state::RobotState kstate(kmodel_);
  kstate.setToDefaultValues();

  ompl::RNG rng;
  std_msgs::ColorRGBA color;
  color.r = 0.0f;
  color.g = 1.0f;
  color.b = 1.0f;
  color.a = 1.0f;
  if (state_storage_->size() < count)
    count = state_storage_->size();

  for (std::size_t i = 0 ; i < count ; ++i)
  {
    state_storage_->getStateSpace()->as<ModelBasedStateSpace>()->copyToRobotState(kstate, state_storage_->getState(rng.uniformInt(0, state_storage_->size() - 1)));
    const Eigen::Vector3d &pos = kstate.getLinkState(link_name)->getGlobalLinkTransform().translation();

    visualization_msgs::Marker mk;
    mk.header.stamp = ros::Time::now();
    mk.header.frame_id = kmodel_->getModelFrame();
    mk.ns = "stored_constraint_data";
    mk.id = i;
    mk.type = visualization_msgs::Marker::SPHERE;
    mk.action = visualization_msgs::Marker::ADD;
    mk.pose.position.x = pos.x();
    mk.pose.position.y = pos.y();
    mk.pose.position.z = pos.z();
    mk.pose.orientation.w = 1.0;
    mk.scale.x = mk.scale.y = mk.scale.z = 0.035;
    mk.color = color;
    mk.lifetime = ros::Duration(30.0);
    arr.markers.push_back(mk);
  }
  }
*/

void ompl_interface::ConstraintsLibrary::loadConstraintApproximations(const std::string &path)
{
  constraint_approximations_.clear();
  std::ifstream fin((path + "/manifest").c_str());
  if (!fin.good())
  {
    logWarn("Manifest not found in folder '%s'. Not loading constraint approximations.", path.c_str());
    return;
  }

  logInform("Loading constrained space approximations from '%s'...", path.c_str());

  while (fin.good() && !fin.eof())
  {
    std::string group, state_space_parameterization, serialization, filename;
    bool explicit_motions;
    unsigned int milestones;
    fin >> group;
    if (fin.eof())
      break;
    fin >> state_space_parameterization;
    if (fin.eof())
      break;
    fin >> explicit_motions;
    if (fin.eof())
      break;
    fin >> milestones;
    if (fin.eof())
      break;
    fin >> serialization;
    if (fin.eof())
      break;
    fin >> filename;
    logInform("Loading constraint approximation of type '%s' for group '%s' from '%s'...", state_space_parameterization.c_str(), group.c_str(), filename.c_str());
    const ModelBasedPlanningContextPtr &pc = context_manager_.getPlanningContext(group, state_space_parameterization);
    if (pc)
    {
      moveit_msgs::Constraints msg;
      hexToMsg(serialization, msg);
      ConstraintApproximationStateStorage *cass = new ConstraintApproximationStateStorage(pc->getOMPLSimpleSetup()->getStateSpace());
      cass->load((path + "/" + filename).c_str());
      ConstraintApproximationPtr cap(new ConstraintApproximation(group, state_space_parameterization, explicit_motions, msg, filename,
                                                                 ompl::base::StateStoragePtr(cass), milestones));
      if (constraint_approximations_.find(cap->getName()) != constraint_approximations_.end())
        logWarn("Overwriting constraint approximation named '%s'", cap->getName().c_str());
      constraint_approximations_[cap->getName()] = cap;
      std::size_t sum = 0;
      for (std::size_t i = 0 ; i < cass->size() ; ++i)
        sum += cass->getMetadata(i).first.size();
      logInform("Loaded %lu states (%lu milestones) and %lu connections (%0.1lf per state) for constraint named '%s'%s",
                cass->size(), cap->getMilestoneCount(), sum, (double)sum / (double)cap->getMilestoneCount(), msg.name.c_str(), explicit_motions ? ". Explicit motions included." : "");
    }
  }
  logInform("Done loading constrained space approximations.");
}

void ompl_interface::ConstraintsLibrary::saveConstraintApproximations(const std::string &path)
{
  logInform("Saving %u constrained space approximations to '%s'", (unsigned int)constraint_approximations_.size(), path.c_str());
  try
  {
    boost::filesystem::create_directories(path);
  }
  catch(...)
  {
  }

  std::ofstream fout((path + "/manifest").c_str());
  if (fout.good())
    for (std::map<std::string, ConstraintApproximationPtr>::const_iterator it = constraint_approximations_.begin() ; it != constraint_approximations_.end() ; ++it)
    {
      fout << it->second->getGroup() << std::endl;
      fout << it->second->getStateSpaceParameterization() << std::endl;
      fout << it->second->hasExplicitMotions() << std::endl;
      fout << it->second->getMilestoneCount() << std::endl;
      std::string serialization;
      msgToHex(it->second->getConstraintsMsg(), serialization);
      fout << serialization << std::endl;
      fout << it->second->getFilename() << std::endl;
      if (it->second->getStateStorage())
        it->second->getStateStorage()->store((path + "/" + it->second->getFilename()).c_str());
    }
  else
    logError("Unable to save constraint approximation to '%s'", path.c_str());
  fout.close();
}

void ompl_interface::ConstraintsLibrary::clearConstraintApproximations()
{
  constraint_approximations_.clear();
}

void ompl_interface::ConstraintsLibrary::printConstraintApproximations(std::ostream &out) const
{
  for (std::map<std::string, ConstraintApproximationPtr>::const_iterator it = constraint_approximations_.begin() ; it != constraint_approximations_.end() ; ++it)
  {
    out << it->second->getGroup() << std::endl;
    out << it->second->getStateSpaceParameterization() << std::endl;
    out << it->second->hasExplicitMotions() << std::endl;
    out << it->second->getMilestoneCount() << std::endl;
    out << it->second->getFilename() << std::endl;
    out << it->second->getConstraintsMsg() << std::endl;
  }
}

const ompl_interface::ConstraintApproximationPtr& ompl_interface::ConstraintsLibrary::getConstraintApproximation(const moveit_msgs::Constraints &msg) const
{
  std::map<std::string, ConstraintApproximationPtr>::const_iterator it = constraint_approximations_.find(msg.name);
  if (it != constraint_approximations_.end())
    return it->second;

  static ConstraintApproximationPtr empty;
  return empty;
}

ompl_interface::ConstraintApproximationConstructionResults
ompl_interface::ConstraintsLibrary::addConstraintApproximation(const moveit_msgs::Constraints &constr, const std::string &group,
                                                               const planning_scene::PlanningSceneConstPtr &scene,
                                                               const ConstraintApproximationConstructionOptions &options)
{
  return addConstraintApproximation(constr, constr, group, scene, options);
}

ompl_interface::ConstraintApproximationConstructionResults
ompl_interface::ConstraintsLibrary::addConstraintApproximation(const moveit_msgs::Constraints &constr_sampling, const moveit_msgs::Constraints &constr_hard,
                                                               const std::string &group, const planning_scene::PlanningSceneConstPtr &scene,
                                                               const ConstraintApproximationConstructionOptions &options)
{
  ConstraintApproximationConstructionResults res;
  ModelBasedPlanningContextPtr pc = context_manager_.getPlanningContext(group, options.state_space_parameterization);
  if (pc)
  {
    pc->clear();
    pc->setPlanningScene(scene);
    pc->setCompleteInitialState(scene->getCurrentState());

    ros::WallTime start = ros::WallTime::now();
    ompl::base::StateStoragePtr ss = constructConstraintApproximation(pc, constr_sampling, constr_hard, options, res);
    logInform("Spent %lf seconds constructing the database", (ros::WallTime::now() - start).toSec());
    if (ss)
    {
      ConstraintApproximationPtr ca(new ConstraintApproximation(group, options.state_space_parameterization, options.explicit_motions, constr_hard, group + "_" +
                                                                boost::posix_time::to_iso_extended_string(boost::posix_time::microsec_clock::universal_time()) + ".ompldb",
                                                                ss, res.milestones));
      if (constraint_approximations_.find(ca->getName()) != constraint_approximations_.end())
        logWarn("Overwriting constraint approximation named '%s'", ca->getName().c_str());
      constraint_approximations_[ca->getName()] = ca;
      res.approx = ca;
    }
    else
      logError("Unable to construct constraint approximation for group '%s'", group.c_str());
  }
  return res;
}

ompl::base::StateStoragePtr ompl_interface::ConstraintsLibrary::constructConstraintApproximation(const ModelBasedPlanningContextPtr &pcontext,
                                                                                                 const moveit_msgs::Constraints &constr_sampling, const moveit_msgs::Constraints &constr_hard,
                                                                                                 const ConstraintApproximationConstructionOptions &options,
                                                                                                 ConstraintApproximationConstructionResults &result)
{
  // state storage structure
  ConstraintApproximationStateStorage *cass = new ConstraintApproximationStateStorage(pcontext->getOMPLStateSpace());
  ob::StateStoragePtr sstor(cass);

  // construct a sampler for the sampling constraints
  kinematic_constraints::KinematicConstraintSet kset(pcontext->getRobotModel());
  robot_state::Transforms no_transforms(pcontext->getRobotModel()->getModelFrame());
  kset.add(constr_hard, no_transforms);

  const robot_state::RobotState &default_state = pcontext->getCompleteInitialRobotState();

  unsigned int attempts = 0;

  double bounds_val = std::numeric_limits<double>::max() / 2.0 - 1.0;
  pcontext->getOMPLStateSpace()->setPlanningVolume(-bounds_val, bounds_val, -bounds_val, bounds_val, -bounds_val, bounds_val);
  pcontext->getOMPLStateSpace()->setup();

  // construct the constrained states

  robot_state::RobotState kstate(default_state);
  const constraint_samplers::ConstraintSamplerManagerPtr &csmng = pcontext->getConstraintSamplerManager();
  ConstrainedSampler *csmp = NULL;
  if (csmng)
  {
    constraint_samplers::ConstraintSamplerPtr cs = csmng->selectSampler(pcontext->getPlanningScene(), pcontext->getJointModelGroup()->getName(), constr_sampling);
    if (cs)
      csmp = new ConstrainedSampler(pcontext.get(), cs);
  }

  ob::StateSamplerPtr ss(csmp ? ob::StateSamplerPtr(csmp) : pcontext->getOMPLStateSpace()->allocDefaultStateSampler());

  ompl::base::ScopedState<> temp(pcontext->getOMPLStateSpace());
  int done = -1;
  bool slow_warn = false;
  ompl::time::point start = ompl::time::now();
  while (sstor->size() < options.samples)
  {
    ++attempts;
    int done_now = 100 * sstor->size() / options.samples;
    if (done != done_now)
    {
      done = done_now;
      logInform("%d%% complete (kept %0.1lf%% sampled states)", done, 100.0 * (double)sstor->size() / (double)attempts);
    }

    if (!slow_warn && attempts > 10 && attempts > sstor->size() * 100)
    {
      slow_warn = true;
      logWarn("Computation of valid state database is very slow...");
    }

    if (attempts > options.samples && sstor->size() == 0)
    {
      logError("Unable to generate any samples");
      break;
    }

    ss->sampleUniform(temp.get());
    pcontext->getOMPLStateSpace()->copyToRobotState(kstate, temp.get());
    if (kset.decide(kstate).satisfied)
    {
      if (sstor->size() < options.samples)
      {
        temp->as<ModelBasedStateSpace::StateType>()->tag = sstor->size();
        sstor->addState(temp.get());
      }
    }
  }

  result.state_sampling_time = ompl::time::seconds(ompl::time::now() - start);
  logInform("Generated %u states in %lf seconds", (unsigned int)sstor->size(), result.state_sampling_time);
  if (csmp)
  {
    result.sampling_success_rate = csmp->getConstrainedSamplingRate();
    logInform("Constrained sampling rate: %lf", result.sampling_success_rate);
  }

  result.milestones = sstor->size();
  if (options.edges_per_sample > 0)
  {
    logInform("Computing graph connections (max %u edges per sample) ...", options.edges_per_sample);
    
    // construct connexions
    const ob::StateSpacePtr &space = pcontext->getOMPLSimpleSetup()->getStateSpace();
    unsigned int milestones = sstor->size();
    std::vector<ob::State*> int_states(options.max_explicit_points, NULL);
    pcontext->getOMPLSimpleSetup()->getSpaceInformation()->allocStates(int_states);
    
    ompl::time::point start = ompl::time::now();
    int good = 0;
    int done = -1;
    
    for (std::size_t j = 0 ; j < milestones ; ++j)
    {
      int done_now = 100 * j / milestones;
      if (done != done_now)
      {
        done = done_now;
        logInform("%d%% complete", done);
      }
      if (cass->getMetadata(j).first.size() >= options.edges_per_sample)
        continue;
      
      const ob::State *sj = sstor->getState(j);
      
      for (std::size_t i = j + 1 ; i < milestones ; ++i)
      {
        if (cass->getMetadata(i).first.size() >= options.edges_per_sample)
          continue;
        double d = space->distance(sstor->getState(i), sj);
        if (d >= options.max_edge_length)
          continue;
        unsigned int isteps = std::min<unsigned int>(options.max_explicit_points, d / options.explicit_points_resolution);
        double step = 1.0 / (double)isteps;
        double remain = 1.0;
        bool ok = true;
        space->interpolate(sstor->getState(i), sj, step, int_states[0]);
        for (unsigned int k = 1 ; k < isteps ; ++k)
        {
          double this_step = step / (1.0 - (k - 1) * step);
          space->interpolate(int_states[k-1], sj, this_step, int_states[k]);
          pcontext->getOMPLStateSpace()->copyToRobotState(kstate, int_states[k]);
          if (!kset.decide(kstate).satisfied)
          {
            ok = false;
            break;
          }
        }
        
        if (ok)
        {
          cass->getMetadata(i).first.push_back(j);
          cass->getMetadata(j).first.push_back(i);
          
          if (options.explicit_motions)
          {
            cass->getMetadata(i).second[j].first = sstor->size();
            for (unsigned int k = 0 ; k < isteps ; ++k)
            {
              int_states[k]->as<ModelBasedStateSpace::StateType>()->tag = -1;
              sstor->addState(int_states[k]);
            }
            cass->getMetadata(i).second[j].second = sstor->size();
            cass->getMetadata(j).second[i] = cass->getMetadata(i).second[j];
          }
          
          good++;
          if (cass->getMetadata(j).first.size() >= options.edges_per_sample)
            break;
        }
      }
    }
    
    result.state_connection_time = ompl::time::seconds(ompl::time::now() - start);
    logInform("Computed possible connexions in %lf seconds. Added %d connexions", result.state_connection_time, good);
    pcontext->getOMPLSimpleSetup()->getSpaceInformation()->freeStates(int_states);
    
    return sstor;
  }
}