get_path_pair {cppRouting} | R Documentation |
Compute shortest path between origin and destination nodes.
get_path_pair(Graph, from, to, algorithm = "Dijkstra", constant = 1)
Graph |
An object generated by cppRouting::makegraph() function. |
from |
A vector of one or more vertices from which shortest paths are calculated (origin). |
to |
A vector of one or more vertices (destination). |
algorithm |
character. "Dijkstra" for uni-directional Dijkstra, "bi" for bi-directional Dijkstra, "A*" or "NBA" for New bi-directional A star .Default to "Dijkstra" |
constant |
numeric. Constant to maintain the heuristic function admissible in A* algorithm. Default to 1, when cost is expressed in the same unit than coordinates. See details |
To perform A*, projected coordinates should be provided in the Graph object. In A* algorithms, euclidean distance is used as heuristic function. To understand how A star algorithm work, see https://en.wikipedia.org/wiki/A*_search_algorithm . To understand the importance of constant parameter, see the package description : https://github.com/vlarmet/cppRouting .
List containing shortest path between from and to.
'from' and 'to' must be the same length.
#Data describing edges of the graph edges<-data.frame(from_vertex=c(0,0,1,1,2,2,3,4,4), to_vertex=c(1,3,2,4,4,5,1,3,5), cost=c(9,2,11,3,5,12,4,1,6)) #Get all nodes nodes<-unique(c(edges$from_vertex,edges$to_vertex)) #Construct directed and undirected graph directed_graph<-makegraph(edges,directed=TRUE) non_directed<-makegraph(edges,directed=FALSE) #Sampling origin and destination nodes origin<-sample(nodes,10,replace=TRUE) destination<-sample(nodes,10,replace=TRUE) #Get distance between origin and destination in the two graphs dir_paths<-get_path_pair(Graph=directed_graph, from=origin, to=destination) non_dir_paths<-get_path_pair(Graph=non_directed, from=origin, to=destination) print(dir_paths) print(non_dir_paths)