etour {PairViz} | R Documentation |
etour
– Constructs a closed eulerian tour on a graph using Hierholzer's algorithm. Returns a vector of node labels. If weighted
is TRUE
constructs a weight-decreasing eulerian using the modified Hierholzer's algorithm. Usually etour
is not called directly, rather the generic function eulerian
is used.
etour(g, start=NULL,weighted=TRUE)
g |
a graph satisfying is_even_graph |
start |
an optional starting node for the tour. |
weighted |
whether tour uses weights |
The supplied graph should satisfyis_even_graph
. If weighted
is TRUE
the lowest weight edge is found, and the tour starts at the
one of its nodes, picking the node with the bigger second-smallest edge weight.
After that the tour follows weight-increasing edges.
If weighted
is FALSE
weights are ignored.
C.B. Hurley and R.W. Oldford
see overview
require(PairViz) g <- mk_even_graph(5) etour(g) g <- mk_even_graph(6) # adds 3 extra edges to g, so all nodes are even etour(g) etour(g, start= "4") # modifies the starting node # On a general graph. v <- LETTERS[1:4] g <- new("graphNEL",nodes=v) g <- addEdge(v[1],v[3:4],g,1:2) g <- addEdge(v[2],v[3:4],g,3:4) etour(g) eulerian(g) # The eulerian wrapper looks after this n <- LETTERS[1:5] g <- new("graphNEL",nodes=n) g <- addEdge(n[1],n[2:3],g) g <-addEdge(n[2],n[3:5],g) g <-addEdge(n[4],n[3],g) is_even_graph(g) etour(mk_even_graph(g))