Fawkes API  Fawkes Development Version
edge_cost_constraint.cpp
1 /***************************************************************************
2  * edge_cost_constraint.cpp - base class for edge cost constraints
3  *
4  * Created: Fri Jul 18 12:11:35 2014
5  * Copyright 2014 Tim Niemueller
6  ****************************************************************************/
7 
8 /* This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU Library General Public License for more details.
17  *
18  * Read the full text in the LICENSE.GPL file in the doc directory.
19  */
20 
21 #include <navgraph/constraints/edge_cost_constraint.h>
22 
23 namespace fawkes {
24 
25 /** @class NavGraphEdgeCostConstraint <navgraph/constraints/edge_cost_constraint.h>
26  * Constraint that can be queried for an edge cost factor.
27  * @author Tim Niemueller
28  *
29  * @fn bool NavGraphEdgeCostConstraint::cost_factor(const fawkes::NavGraphNode &from, const fawkes::NavGraphNode &to) throw() = 0
30  * Get cost factor for given edge.
31  * This method must be implemented by constraint classes. It is called
32  * to determine a cost factor for an edge. That is, the path costs
33  * from the originating node to the destination node are multiplied
34  * with this factor and thus the chance of following that specific
35  * edge is decreased. The factor must be greater or equal to 1. That
36  * is a requirement to keep heuristics admissible and thus the search
37  * optimal.
38  *
39  * Note that the nodes may be passed in either ordering, therefore
40  * you should not rely on a particular order, not even for directed
41  * nodes!
42  *
43  * Further note that the method may not throw an exception. Handle
44  * this internally appropriately.
45  *
46  * @param from node from which the edge originates
47  * @param to node to which the edge leads
48  * @return cost factor, a number x >= 1.0
49  *
50  * @var std::string NavGraphEdgeCostConstraint::name_
51  * Name of constraint.
52  */
53 
54 /** Constructor.
55  * @param name name of edge constraint
56  */
58 {
59  name_ = name;
60 }
61 
62 /** Constructor.
63  * @param name name of edge constraint
64  */
66 {
67  name_ = name;
68 }
69 
70 /** Virtual empty destructor. */
72 {
73 }
74 
75 /** Get name of constraint.
76  * @return name of constraint
77  */
78 std::string
80 {
81  return name_;
82 }
83 
84 /** Perform compuations before graph search and to indicate re-planning.
85  * The compute method is called on all constraints just before a path
86  * search is performed and to check if re-planning should be tried.
87  *
88  * It can be used for example to cache results for the coming search
89  * run. The search guarantees that for each complete search run
90  * compute() is called once and only once and that no two search runs
91  * overlap, i.e., compute() will not be called while another search is
92  * still running.
93  *
94  * Constraints must indicate whether any change has occured during
95  * computation or since the last compute() call through the return
96  * value. This is used to determine if re-planning should be
97  * attempted.
98  *
99  * @return true if a change has occured during computation or since
100  * the last call, false otherwise
101  */
102 bool
104 {
105  return false;
106 }
107 
108 /** Check if constraint matches name.
109  * @param name name string to compare this constraints name to
110  * @return true if the given name is the same as this constraint's name,
111  * false otherwise
112  */
113 bool
114 NavGraphEdgeCostConstraint::operator==(const std::string &name) const
115 {
116  return name_ == name;
117 }
118 
119 } // end of namespace fawkes
fawkes::NavGraphEdgeCostConstraint::name_
std::string name_
Definition: edge_cost_constraint.h:54
fawkes::NavGraphEdgeCostConstraint::compute
virtual bool compute(void)
Perform compuations before graph search and to indicate re-planning.
Definition: edge_cost_constraint.cpp:108
fawkes::NavGraphEdgeCostConstraint::operator==
bool operator==(const std::string &name) const
Check if constraint matches name.
Definition: edge_cost_constraint.cpp:119
fawkes
fawkes::NavGraphEdgeCostConstraint::~NavGraphEdgeCostConstraint
virtual ~NavGraphEdgeCostConstraint()
Virtual empty destructor.
Definition: edge_cost_constraint.cpp:76
fawkes::NavGraphEdgeCostConstraint::NavGraphEdgeCostConstraint
NavGraphEdgeCostConstraint(std::string &name)
Constructor.
Definition: edge_cost_constraint.cpp:62
fawkes::NavGraphEdgeCostConstraint::name
std::string name()
Get name of constraint.
Definition: edge_cost_constraint.cpp:84