HillClimbing.cpp
1 /*********************************************************************
2 * Software License Agreement (BSD License)
3 *
4 * Copyright (c) 2008, Willow Garage, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
17 * * Neither the name of the Willow Garage nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
29 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
31 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 *********************************************************************/
34 
35 /* Author: Ioan Sucan */
36 
37 #include "ompl/geometric/HillClimbing.h"
38 
39 namespace ompl
40 {
41  namespace magic
42  {
47  static const unsigned int MAX_CLIMB_NO_UPDATE_STEPS = 10;
48  }
49 }
50 
51 bool ompl::geometric::HillClimbing::tryToImprove(const base::GoalRegion &goal, base::State *state, double nearDistance,
52  double *betterGoalDistance) const
53 {
54  double tempDistance;
55  double initialDistance;
56 
57  bool wasValid = valid(state);
58  bool wasValidStart = wasValid;
59 
60  bool wasSatisfied = goal.isSatisfied(state, &initialDistance);
61  bool wasSatisfiedStart = wasSatisfied;
62 
63  double bestDist = initialDistance;
64 
65  base::StateSamplerPtr ss = si_->allocStateSampler();
66  base::State *test = si_->allocState();
67  unsigned int noUpdateSteps = 0;
68 
69  for (unsigned int i = 0; noUpdateSteps < magic::MAX_CLIMB_NO_UPDATE_STEPS && i < maxImproveSteps_; ++i)
70  {
71  bool update = false;
72  ss->sampleUniformNear(test, state, nearDistance);
73  bool isValid = valid(test);
74  bool isSatisfied = goal.isSatisfied(test, &tempDistance);
75  if (!wasValid && isValid)
76  {
77  si_->copyState(state, test);
78  wasValid = true;
79  wasSatisfied = isSatisfied;
80  update = true;
81  }
82  else if (wasValid == isValid)
83  {
84  if (!wasSatisfied && isSatisfied)
85  {
86  si_->copyState(state, test);
87  wasSatisfied = true;
88  update = true;
89  }
90  else if (wasSatisfied == isSatisfied)
91  {
92  if (tempDistance < bestDist)
93  {
94  si_->copyState(state, test);
95  bestDist = tempDistance;
96  update = true;
97  }
98  }
99  }
100  if (update)
101  noUpdateSteps = 0;
102  else
103  noUpdateSteps++;
104  }
105  si_->freeState(test);
106 
107  if (betterGoalDistance)
108  *betterGoalDistance = bestDist;
109  return (bestDist < initialDistance) || (!wasSatisfiedStart && wasSatisfied) || (!wasValidStart && wasValid);
110 }
bool tryToImprove(const base::GoalRegion &goal, base::State *state, double nearDistance, double *betterGoalDistance=nullptr) const
Try to improve a state (reduce distance to goal). The updates are performed by sampling near the stat...
Definition of a goal region.
Definition: GoalRegion.h:111
Definition of an abstract state.
Definition: State.h:113
static const unsigned int MAX_CLIMB_NO_UPDATE_STEPS
Maximum number of consecutive failures to allow before giving up on improving a state....
Main namespace. Contains everything in this library.
Definition: AppBase.h:21