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SimpleDirectedControlSampler.cpp
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34 
35 /* Author: Ioan Sucan */
36 
37 #include "ompl/control/SimpleDirectedControlSampler.h"
38 #include "ompl/control/SpaceInformation.h"
39 
41  DirectedControlSampler(si), cs_(si->allocControlSampler()), numControlSamples_(k)
42 {
43 }
44 
45 ompl::control::SimpleDirectedControlSampler::~SimpleDirectedControlSampler(void)
46 {
47 }
48 
49 unsigned int ompl::control::SimpleDirectedControlSampler::sampleTo(Control *control, const base::State *source, const base::State *target)
50 {
51  return getBestControl(control, source, target, NULL);
52 }
53 
54 unsigned int ompl::control::SimpleDirectedControlSampler::sampleTo(Control *control, const Control *previous, const base::State *source, const base::State *target)
55 {
56  return getBestControl(control, source, target, previous);
57 }
58 
59 unsigned int ompl::control::SimpleDirectedControlSampler::getBestControl (Control *control, const base::State *source, const base::State *target, const Control *previous)
60 {
61  // Sample the first control
62  if (previous)
63  cs_->sampleNext(control, previous, source);
64  else
65  cs_->sample(control, source);
66 
67  const double minDuration = si_->getMinControlDuration();
68  const double maxDuration = si_->getMaxControlDuration();
69 
70  unsigned int steps = cs_->sampleStepCount(minDuration, maxDuration);
71 
72  if (numControlSamples_ > 1)
73  {
74  Control *tempControl = si_->allocControl();
75  base::State *tempState = si_->allocState();
76 
77  // Propagate the first control, and find how far it is from the target state
78  si_->propagateWhileValid(source, control, steps, tempState);
79  double bestDistance = si_->distance(tempState, target);
80 
81  // Sample k-1 more controls, and save the control that gets closest to target
82  for (unsigned int i = 1; i < numControlSamples_; ++i)
83  {
84  unsigned int sampleSteps = cs_->sampleStepCount(minDuration, maxDuration);
85  if (previous)
86  cs_->sampleNext(tempControl, previous, source);
87  else
88  cs_->sample(tempControl, source);
89 
90  si_->propagateWhileValid(source, tempControl, sampleSteps, tempState);
91  double tempDistance = si_->distance(tempState, target);
92  if (tempDistance < bestDistance)
93  {
94  si_->copyControl(control, tempControl);
95  bestDistance = tempDistance;
96  steps = sampleSteps;
97  }
98  }
99 
100  si_->freeControl(tempControl);
101  si_->freeState(tempState);
102  }
103  return steps;
104 }