#include <lemon/bfs.h>
Inherited by Bfs::DefDistMap, Bfs::DefPredMap, Bfs::DefProcessedMap, Bfs::DefProcessedMapToBeDefaultMap, and Bfs::DefReachedMap.
Inheritance diagram for Bfs:
GR | The graph type the algorithm runs on. The default value is ListGraph. The value of GR is not used directly by Bfs, it is only passed to BfsDefaultTraits. | |
TR | Traits class to set various data types used by the algorithm. The default traits class is BfsDefaultTraits<GR>. See BfsDefaultTraits for the documentation of a Bfs traits class. |
Public Types | |
typedef TR::Graph | Graph |
The type of the underlying graph. | |
typedef Graph::Node | Node |
| |
typedef Graph::NodeIt | NodeIt |
| |
typedef Graph::Edge | Edge |
| |
typedef Graph::OutEdgeIt | OutEdgeIt |
| |
typedef TR::PredMap | PredMap |
The type of the map that stores the last edges of the shortest paths. | |
typedef TR::ReachedMap | ReachedMap |
The type of the map indicating which nodes are reached. | |
typedef TR::ProcessedMap | ProcessedMap |
The type of the map indicating which nodes are processed. | |
typedef TR::DistMap | DistMap |
The type of the map that stores the dists of the nodes. | |
Public Member Functions | |
Bfs (const Graph &_G) | |
Constructor. | |
~Bfs () | |
Destructor. | |
Bfs & | predMap (PredMap &m) |
Sets the map storing the predecessor edges. | |
Bfs & | reachedMap (ReachedMap &m) |
Sets the map indicating the reached nodes. | |
Bfs & | processedMap (ProcessedMap &m) |
Sets the map indicating the processed nodes. | |
Bfs & | distMap (DistMap &m) |
Sets the map storing the distances calculated by the algorithm. | |
Execution control | |
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. | |
void | init () |
Initializes the internal data structures. | |
void | addSource (Node s) |
Adds a new source node. | |
Node | processNextNode () |
Processes the next node. | |
Node | nextNode () |
Next node to be processed. | |
bool | emptyQueue () |
Returns false if there are nodes to be processed in the queue. | |
int | queueSize () |
Returns the number of the nodes to be processed. | |
void | start () |
Executes the algorithm. | |
void | start (Node dest) |
Executes the algorithm until dest is reached. | |
template<class NM> | |
void | start (const NM &nm) |
Executes the algorithm until a condition is met. | |
void | run (Node s) |
Runs BFS algorithm from node s . | |
int | run (Node s, Node t) |
Finds the shortest path between s and t . | |
Query Functions | |
The result of the BFS algorithm can be obtained using these functions. Before the use of these functions, either run() or start() must be called. | |
template<class P> | |
bool | getPath (P &p, Node t) |
Copies the shortest path to t into p . | |
int | dist (Node v) const |
The distance of a node from the root(s). | |
Edge | predEdge (Node v) const |
Returns the 'previous edge' of the shortest path tree. | |
Node | predNode (Node v) const |
Returns the 'previous node' of the shortest path tree. | |
const DistMap & | distMap () const |
Returns a reference to the NodeMap of distances. | |
const PredMap & | predMap () const |
Returns a reference to the shortest path tree map. | |
bool | reached (Node v) |
Checks if a node is reachable from the root. | |
Private Member Functions | |
void | create_maps () |
Private Attributes | |
const Graph * | G |
Pointer to the underlying graph. | |
PredMap * | _pred |
Pointer to the map of predecessors edges. | |
bool | local_pred |
Indicates if _pred is locally allocated (true ) or not. | |
DistMap * | _dist |
Pointer to the map of distances. | |
bool | local_dist |
Indicates if _dist is locally allocated (true ) or not. | |
ReachedMap * | _reached |
Pointer to the map of reached status of the nodes. | |
bool | local_reached |
Indicates if _reached is locally allocated (true ) or not. | |
ProcessedMap * | _processed |
Pointer to the map of processed status of the nodes. | |
bool | local_processed |
Indicates if _processed is locally allocated (true ) or not. | |
Classes | |
struct | DefDistMap |
Named parameter for setting DistMap type More... | |
struct | DefPredMap |
Named parameter for setting PredMap type More... | |
struct | DefProcessedMap |
Named parameter for setting ProcessedMap type More... | |
struct | DefProcessedMapToBeDefaultMap |
Named parameter for setting the ProcessedMap type to be Graph::NodeMap<bool>. More... | |
struct | DefReachedMap |
Named parameter for setting ReachedMap type More... | |
class | UninitializedParameter |
Exception for uninitialized parameters. More... |
void create_maps | ( | ) | [inline, private] |
Sets the map storing the predecessor edges. If you don't use this function before calling run(), it will allocate one. The destructor deallocates this automatically allocated map, of course.
(*this)
Bfs& reachedMap | ( | ReachedMap & | m | ) | [inline] |
Sets the map indicating the reached nodes. If you don't use this function before calling run(), it will allocate one. The destructor deallocates this automatically allocated map, of course.
(*this)
Bfs& processedMap | ( | ProcessedMap & | m | ) | [inline] |
Sets the map indicating the processed nodes. If you don't use this function before calling run(), it will allocate one. The destructor deallocates this automatically allocated map, of course.
(*this)
Sets the map storing the distances calculated by the algorithm. If you don't use this function before calling run(), it will allocate one. The destructor deallocates this automatically allocated map, of course.
(*this)
void init | ( | ) | [inline] |
Initializes the internal data structures.
void addSource | ( | Node | s | ) | [inline] |
Adds a new source node to the set of nodes to be processed.
Node processNextNode | ( | ) | [inline] |
Processes the next node.
Node nextNode | ( | ) | [inline] |
Next node to be processed.
bool emptyQueue | ( | ) | [inline] |
Returns false
if there are nodes to be processed in the queue
int queueSize | ( | ) | [inline] |
Returns the number of the nodes to be processed in the queue.
void start | ( | ) | [inline] |
Executes the algorithm.
void start | ( | Node | dest | ) | [inline] |
Executes the algorithm until dest
is reached.
dest
. The algorithm computesdest
.dest
from the root(s). void start | ( | const NM & | nm | ) | [inline] |
Executes the algorithm until a condition is met.
nm | must be a bool (or convertible) node map. The algorithm will stop when it reaches a node v with nm[v]==true . |
void run | ( | Node | s | ) | [inline] |
This method runs the BFS algorithm from a root node s
in order to compute the shortest path to each node. The algorithm computes
d.init(); d.addSource(s); d.start();
Finds the shortest path between s
and t
.
d.init(); d.addSource(s); d.start(t);
bool getPath | ( | P & | p, | |
Node | t | |||
) | [inline] |
This function copies the shortest path to t
into p
. If t
is a source itself or unreachable, then it does not alter p
.
true
if a path to t
was actually copied to p
, false
otherwise. int dist | ( | Node | v | ) | const [inline] |
Returns the distance of a node from the root(s).
v
in unreachable from the root(s) the return value of this function is undefined.
For a node v
it returns the 'previous edge' of the shortest path tree, i.e. it returns the last edge of a shortest path from the root(s) to v
. It is INVALID if v
is unreachable from the root(s) or v
is a root. The shortest path tree used here is equal to the shortest path tree used in predNode().
For a node v
it returns the 'previous node' of the shortest path tree, i.e. it returns the last but one node from a shortest path from the root(a) to /v
. It is INVALID if v
is unreachable from the root(s) or if v
itself a root. The shortest path tree used here is equal to the shortest path tree used in predEdge().
const DistMap& distMap | ( | ) | const [inline] |
const PredMap& predMap | ( | ) | const [inline] |
bool reached | ( | Node | v | ) | [inline] |