constrained_goal_sampler.cpp

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/* Author: Ioan Sucan */

#include <moveit/ompl_interface/detail/constrained_goal_sampler.h>
#include <moveit/ompl_interface/model_based_planning_context.h>
#include <moveit/ompl_interface/detail/state_validity_checker.h>
#include <moveit/profiler/profiler.h>

ompl_interface::ConstrainedGoalSampler::ConstrainedGoalSampler(const ModelBasedPlanningContext *pc,
                                                               const kinematic_constraints::KinematicConstraintSetPtr &ks,
                                                               const constraint_samplers::ConstraintSamplerPtr &cs) 
  : ob::GoalLazySamples(pc->getOMPLSimpleSetup()->getSpaceInformation(),
                        boost::bind(&ConstrainedGoalSampler::sampleUsingConstraintSampler, this, _1, _2), false)
  , planning_context_(pc)
  , kinematic_constraint_set_(ks)
  , constraint_sampler_(cs)
  , work_state_(pc->getCompleteInitialRobotState())
  , invalid_sampled_constraints_(0)
  , warned_invalid_samples_(false)
  , verbose_display_(0)
{
  if (!constraint_sampler_)
    default_sampler_ = si_->allocStateSampler();
  logDebug("Constructed a ConstrainedGoalSampler instance at address %p", this);
  startSampling();
}

bool ompl_interface::ConstrainedGoalSampler::checkStateValidity(ob::State* new_goal,
                                                                const robot_state::RobotState& state,
                                                                bool verbose) const
{
  planning_context_->getOMPLStateSpace()->copyToOMPLState(new_goal, state);
  return static_cast<const StateValidityChecker*>(si_->getStateValidityChecker().get())->isValid(new_goal, verbose);
}

bool ompl_interface::ConstrainedGoalSampler::stateValidityCallback(ob::State* new_goal, 
                                                                   robot_state::RobotState const* state,
                                                                   const robot_model::JointModelGroup* jmg,
                                                                   const double* jpos,
                                                                   bool verbose) const
{
  // we copy the state to not change the seed state
  robot_state::RobotState solution_state( *state );
  solution_state.setJointGroupPositions(jmg, jpos);
  solution_state.update();
  return checkStateValidity(new_goal, solution_state, verbose);
}

bool ompl_interface::ConstrainedGoalSampler::sampleUsingConstraintSampler(const ob::GoalLazySamples *gls, ob::State *new_goal)
{
  //  moveit::Profiler::ScopedBlock sblock("ConstrainedGoalSampler::sampleUsingConstraintSampler");
  
  unsigned int max_attempts = planning_context_->getMaximumGoalSamplingAttempts();
  unsigned int attempts_so_far = gls->samplingAttemptsCount();
  
  // terminate after too many attempts
  if (attempts_so_far >= max_attempts)
    return false;
  
  // terminate after a maximum number of samples
  if (gls->getStateCount() >= planning_context_->getMaximumGoalSamples())
    return false;
  
  // terminate the sampling thread when a solution has been found
  if (planning_context_->getOMPLSimpleSetup()->getProblemDefinition()->hasSolution())
    return false;

  unsigned int max_attempts_div2 = max_attempts/2;
  for (unsigned int a = gls->samplingAttemptsCount() ; a < max_attempts && gls->isSampling() ; ++a)
  {
    bool verbose = false;
    if (gls->getStateCount() == 0 && a >= max_attempts_div2)
      if (verbose_display_ < 1)
      {
        verbose = true;
        verbose_display_++;
      }
    
    if (constraint_sampler_)
    {
      // makes the constraint sampler also perform a validity callback
      robot_state::GroupStateValidityCallbackFn gsvcf = boost::bind(&ompl_interface::ConstrainedGoalSampler::stateValidityCallback,
                                                                    this,
                                                                    new_goal, 
                                                                    _1,  // pointer to state 
                                                                    _2,  // const* joint model group
                                                                    _3,  // double* of joint positions
                                                                    verbose);
      constraint_sampler_->setGroupStateValidityCallback( gsvcf );

      if (constraint_sampler_->project(work_state_, planning_context_->getMaximumStateSamplingAttempts()))
      {
        work_state_.update();
        if (kinematic_constraint_set_->decide(work_state_, verbose).satisfied)
        {
          if (checkStateValidity(new_goal, work_state_, verbose))
            return true;
        }
        else
        {
          invalid_sampled_constraints_++;
          if (!warned_invalid_samples_ && invalid_sampled_constraints_ >= (attempts_so_far * 8) / 10)
          {
            warned_invalid_samples_ = true;
            logWarn("More than 80%% of the sampled goal states fail to satisfy the constraints imposed on the goal sampler. Is the constrained sampler working correctly?");
          }
        }
      }
    }
    else
    {
      default_sampler_->sampleUniform(new_goal);
      if (static_cast<const StateValidityChecker*>(si_->getStateValidityChecker().get())->isValid(new_goal, verbose))
      {
        planning_context_->getOMPLStateSpace()->copyToRobotState(work_state_, new_goal);
        if (kinematic_constraint_set_->decide(work_state_, verbose).satisfied)
          return true;
      }
    }
  }
  return false;
}