The Bellman-Ford algorithm solves the shortest path from one node problem when the edges can have negative length but the graph should not contain cycles with negative sum of length. If we can assume that all edge is non-negative in the graph then the dijkstra algorithm should be used rather.
The complexity of the algorithm is O(n * e).
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Public Types |
typedef _Traits::Graph | Graph |
| The type of the underlying graph.
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typedef _Traits::LengthMap::Value | Value |
| The type of the length of the edges.
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typedef _Traits::LengthMap | LengthMap |
| The type of the map that stores the edge lengths.
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typedef _Traits::PredMap | PredMap |
| The type of the map that stores the last edges of the shortest paths.
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typedef _Traits::DistMap | DistMap |
| The type of the map that stores the dists of the nodes.
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typedef _Traits::OperationTraits | OperationTraits |
| The operation traits.
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Public Member Functions |
| BellmanFord (const Graph &_graph, const LengthMap &_length) |
| Constructor.
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| ~BellmanFord () |
| Destructor.
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BellmanFord & | lengthMap (const LengthMap &m) |
| Sets the length map.
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BellmanFord & | predMap (PredMap &m) |
| Sets the map storing the predecessor edges.
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BellmanFord & | distMap (DistMap &m) |
| Sets the map storing the distances calculated by the algorithm.
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The simplest way to execute the algorithm is to use one of the member functions called run (...).
If you need more control on the execution, first you must call init(), then you can add several source nodes with addSource(). Finally start() will perform the actual path computation.
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void | init (const Value value=OperationTraits::infinity()) |
| Initializes the internal data structures.
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void | addSource (Node source, Value dst=OperationTraits::zero()) |
| Adds a new source node.
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bool | processNextRound () |
| Executes one round from the bellman ford algorithm.
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bool | processNextWeakRound () |
| Executes one weak round from the bellman ford algorithm.
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void | start () |
| Executes the algorithm.
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bool | checkedStart () |
| Executes the algorithm and checks the negative cycles.
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void | limitedStart (int length) |
| Executes the algorithm with path length limit.
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void | run (Node s) |
| Runs BellmanFord algorithm from node s .
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void | run (Node s, int len) |
| Runs BellmanFord algorithm with limited path length from node s .
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The result of the BellmanFord algorithm can be obtained using these functions.
Before the use of these functions, either run() or start() must be called.
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template<typename Path> |
bool | getPath (Path &p, Node t) |
| Copies the shortest path to t into p .
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Value | dist (Node v) const |
| The distance of a node from the root.
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Edge | predEdge (Node v) const |
| Returns the 'previous edge' of the shortest path tree.
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Node | predNode (Node v) const |
| Returns the 'previous node' of the shortest path tree.
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const DistMap & | distMap () const |
| Returns a reference to the NodeMap of distances.
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const PredMap & | predMap () const |
| Returns a reference to the shortest path tree map.
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bool | reached (Node v) |
| Checks if a node is reachable from the root.
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Classes |
struct | DefDistMap |
| Named parameter for setting DistMap type More...
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struct | DefOperationTraits |
| Named parameter for setting OperationTraits type More...
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struct | DefPredMap |
| Named parameter for setting PredMap type Named parameter for setting PredMap type More...
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class | UninitializedParameter |
| Exception for uninitialized parameters. More...
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