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mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION > Class Template Reference

Detailed Description

template<class TYPE_GRAPH, class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
class mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >

The Dijkstra algorithm for finding the shortest path between a given source node in a (weighted) directed graph and all other nodes in the form of a tree.

The constructor takes as input the graph (the set of directed edges) computes all the needed data, then successive calls to getShortestPathTo return the paths efficiently from the root.

The entire generated tree can be also retrieved with getTreeGraph.

Input graphs are represented by instances of (or classes derived from) mrpt::graphs::CDirectedGraph, and node's IDs are uint64_t values, although the type mrpt::graphs::TNodeID is also provided for clarity in the code.

The second template argument MAPS_IMPLEMENTATION allows choosing between a sparse std::map<> representation (using * mrpt::containers::map_traits_stdmap) for several intermediary and final results, and an alternative (using mrpt::containers::map_traits_map_as_vector as argument) dense implementation which is much faster, but can be only used if the TNodeID's start in 0 or a low value.

See <a href="http://www.mrpt.org/Example:Dijkstra_optimal_path_search_in_graphs"

this page for a complete example.

Definition at line 97 of file dijkstra.h.

#include <mrpt/graphs/dijkstra.h>

Classes

struct  TDistance
 Auxiliary struct for topological distances from root node. More...
 
struct  TPrevious
 Auxiliary struct for backward paths. More...
 

Public Types

Useful typedefs
using graph_t = TYPE_GRAPH
 The type of the graph, typically a mrpt::graphs::CDirectedGraph<> or any other derived class. More...
 
using edge_t = typename graph_t::edge_t
 The type of edge data in graph_t. More...
 
using edge_list_t = std::list< TPairNodeIDs >
 A list of edges used to describe a path on the graph. More...
 
using functor_edge_weight_t = std::function< double(const graph_t &graph, const TNodeID id_from, const TNodeID id_to, const edge_t &edge)>
 
using functor_on_progress_t = std::function< void(const graph_t &graph, size_t visitedCount)>
 

Public Member Functions

 CDijkstra (const graph_t &graph, const TNodeID source_node_ID, functor_edge_weight_t functor_edge_weight=functor_edge_weight_t(), functor_on_progress_t functor_on_progress=functor_on_progress_t())
 Constructor which takes the input graph and executes the entire Dijkstra algorithm from the given root node ID. More...
 

Protected Types

using list_all_neighbors_t = typename MAPS_IMPLEMENTATION::template map< TNodeID, std::set< TNodeID > >
 A std::map (or a similar container according to MAPS_IMPLEMENTATION) with all the neighbors of every node. More...
 
using id2pairIDs_map_t = typename MAPS_IMPLEMENTATION::template map< TNodeID, TPairNodeIDs >
 
using id2dist_map_t = typename MAPS_IMPLEMENTATION::template map< TNodeID, TDistance >
 
using id2id_map_t = typename MAPS_IMPLEMENTATION::template map< TNodeID, TPrevious >
 

Protected Attributes

const TYPE_GRAPH & m_cached_graph
 
const TNodeID m_source_node_ID
 
id2dist_map_t m_distances
 All the distances. More...
 
std::map< TNodeID, TDistancem_distances_non_visited
 
id2id_map_t m_prev_node
 
id2pairIDs_map_t m_prev_arc
 
std::set< TNodeIDm_lstNode_IDs
 
list_all_neighbors_t m_allNeighbors
 

Query Dijkstra results

using tree_graph_t = CDirectedTree< const edge_t * >
 Type for graph returned by getTreeGraph: a graph like the original input graph, but with edge data being pointers to the original data (to save copy time & memory) More...
 
double getNodeDistanceToRoot (const TNodeID id) const
 Return the distance from the root node to any other node using the Dijkstra-generated tree. More...
 
const std::set< TNodeID > & getListOfAllNodes () const
 Return the set of all known node IDs (actually, a const ref to the internal set object). More...
 
TNodeID getRootNodeID () const
 Return the node ID of the tree root, as passed in the constructor. More...
 
const list_all_neighbors_tgetCachedAdjacencyMatrix () const
 Return the adjacency matrix of the input graph, which is cached at construction so if needed later just use this copy to avoid recomputing it. More...
 
void getShortestPathTo (const TNodeID target_node_ID, edge_list_t &out_path) const
 Returns the shortest path between the source node passed in the constructor and the given target node. More...
 
void getTreeGraph (tree_graph_t &out_tree) const
 Returns a tree representation of the graph, as determined by the Dijkstra shortest paths from the root node. More...
 

Member Typedef Documentation

◆ edge_list_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::edge_list_t = std::list<TPairNodeIDs>

A list of edges used to describe a path on the graph.

Definition at line 156 of file dijkstra.h.

◆ edge_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::edge_t = typename graph_t::edge_t

The type of edge data in graph_t.

Definition at line 154 of file dijkstra.h.

◆ functor_edge_weight_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::functor_edge_weight_t = std::function<double( const graph_t& graph, const TNodeID id_from, const TNodeID id_to, const edge_t& edge)>

Definition at line 160 of file dijkstra.h.

◆ functor_on_progress_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::functor_on_progress_t = std::function<void(const graph_t& graph, size_t visitedCount)>

Definition at line 163 of file dijkstra.h.

◆ graph_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::graph_t = TYPE_GRAPH

The type of the graph, typically a mrpt::graphs::CDirectedGraph<> or any other derived class.

Definition at line 152 of file dijkstra.h.

◆ id2dist_map_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::id2dist_map_t = typename MAPS_IMPLEMENTATION::template map<TNodeID, TDistance>
protected

Definition at line 132 of file dijkstra.h.

◆ id2id_map_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::id2id_map_t = typename MAPS_IMPLEMENTATION::template map<TNodeID, TPrevious>
protected

Definition at line 134 of file dijkstra.h.

◆ id2pairIDs_map_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::id2pairIDs_map_t = typename MAPS_IMPLEMENTATION::template map<TNodeID, TPairNodeIDs>
protected

Definition at line 130 of file dijkstra.h.

◆ list_all_neighbors_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::list_all_neighbors_t = typename MAPS_IMPLEMENTATION::template map<TNodeID, std::set<TNodeID> >
protected

A std::map (or a similar container according to MAPS_IMPLEMENTATION) with all the neighbors of every node.

Definition at line 128 of file dijkstra.h.

◆ tree_graph_t

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
using mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::tree_graph_t = CDirectedTree<const edge_t*>

Type for graph returned by getTreeGraph: a graph like the original input graph, but with edge data being pointers to the original data (to save copy time & memory)

Definition at line 439 of file dijkstra.h.

Constructor & Destructor Documentation

◆ CDijkstra()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::CDijkstra ( const graph_t graph,
const TNodeID  source_node_ID,
functor_edge_weight_t  functor_edge_weight = functor_edge_weight_t(),
functor_on_progress_t  functor_on_progress = functor_on_progress_t() 
)
inline

Constructor which takes the input graph and executes the entire Dijkstra algorithm from the given root node ID.

The graph is given by the set of directed edges, stored in a mrpt::graphs::CDirectedGraph class.

If a function functor_edge_weight is provided, it will be used to compute the weight of edges. Otherwise, all edges weight the unity.

After construction, call getShortestPathTo to get the shortest path to a node or getTreeGraph for the tree representation.

See also
getShortestPathTo, getTreeGraph
Exceptions
std::exceptionIf the source nodeID is not found in the graph

Definition at line 184 of file dijkstra.h.

References ASSERT_, INVALID_NODEID, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_allNeighbors, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_distances, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_distances_non_visited, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_lstNode_IDs, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_arc, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_node, and THROW_EXCEPTION_FMT.

Member Function Documentation

◆ getCachedAdjacencyMatrix()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
const list_all_neighbors_t& mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::getCachedAdjacencyMatrix ( ) const
inline

Return the adjacency matrix of the input graph, which is cached at construction so if needed later just use this copy to avoid recomputing it.

See also
mrpt::graphs::CDirectedGraph::getAdjacencyMatrix

Definition at line 402 of file dijkstra.h.

References mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_allNeighbors.

◆ getListOfAllNodes()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
const std::set<TNodeID>& mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::getListOfAllNodes ( ) const
inline

Return the set of all known node IDs (actually, a const ref to the internal set object).

Definition at line 389 of file dijkstra.h.

References mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_lstNode_IDs.

◆ getNodeDistanceToRoot()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
double mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::getNodeDistanceToRoot ( const TNodeID  id) const
inline

Return the distance from the root node to any other node using the Dijkstra-generated tree.

Exceptions
std::exceptionOn unknown node ID

Definition at line 378 of file dijkstra.h.

References mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_distances, and THROW_EXCEPTION.

◆ getRootNodeID()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
TNodeID mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::getRootNodeID ( ) const
inline

Return the node ID of the tree root, as passed in the constructor.

Definition at line 395 of file dijkstra.h.

References mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_source_node_ID.

◆ getShortestPathTo()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
void mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::getShortestPathTo ( const TNodeID  target_node_ID,
edge_list_t out_path 
) const
inline

Returns the shortest path between the source node passed in the constructor and the given target node.

The reconstructed path contains a list of arcs (all of them exist in the graph with the given direction), such as the the first edge starts at the origin passed in the constructor, and the last one contains the given target.

Note
An empty list of edges is returned when target equals the source node.
See also
getTreeGraph

Definition at line 418 of file dijkstra.h.

References ASSERT_, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_arc, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_node, and mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_source_node_ID.

◆ getTreeGraph()

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
void mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::getTreeGraph ( tree_graph_t out_tree) const
inline

Returns a tree representation of the graph, as determined by the Dijkstra shortest paths from the root node.

Note that the annotations on each edge in the tree are "const pointers" to the original graph edge data, so it's mandatory for the original input graph not to be deleted as long as this tree is used.

See also
getShortestPathTo

Definition at line 449 of file dijkstra.h.

References ASSERTMSG_, mrpt::graphs::CDirectedTree< TYPE_EDGES >::clear(), mrpt::graphs::CDirectedTree< TYPE_EDGES >::edges_to_children, mrpt::format(), mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_cached_graph, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_arc, mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_source_node_ID, and mrpt::graphs::CDirectedTree< TYPE_EDGES >::root.

Here is the call graph for this function:

Member Data Documentation

◆ m_allNeighbors

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
list_all_neighbors_t mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_allNeighbors
protected

◆ m_cached_graph

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
const TYPE_GRAPH& mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_cached_graph
protected

◆ m_distances

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
id2dist_map_t mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_distances
protected

◆ m_distances_non_visited

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
std::map<TNodeID, TDistance> mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_distances_non_visited
protected

◆ m_lstNode_IDs

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
std::set<TNodeID> mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_lstNode_IDs
protected

◆ m_prev_arc

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
id2pairIDs_map_t mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_arc
protected

◆ m_prev_node

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
id2id_map_t mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_prev_node
protected

◆ m_source_node_ID

template<class TYPE_GRAPH , class MAPS_IMPLEMENTATION = mrpt::containers::map_traits_stdmap>
const TNodeID mrpt::graphs::CDijkstra< TYPE_GRAPH, MAPS_IMPLEMENTATION >::m_source_node_ID
protected



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