
Last chance! 50% off unlimited learning
Sale ends in
Returns a path, if it exists, from the start
to the end
.
getpath(x, start, end, …)
# S3 method for mathgraph
getpath(x, start, end, …)
an object representing a mathematical graph.
character string or integer giving the starting node.
character string or integer giving the ending node.
generic arguments.
When at least one path exists, a "mathgraph"
object containing
the edges within the first path found;
this may be an empty mathgraph if start
and end
are equal.
When no path exists, returns NULL
.
getpath
is a generic function with methods for
"mathgraph"
, "incidmat"
and "adjamat"
.
The default method converts x
to class "incidmat"
.
getpath.adjamat
is an implementation of algorithm 2.2 in Chachra,
Ghare and Moore (1979) and getpath.incidmat
is an implementation
of their algorithm 2.3.
The distinction between non-existent paths and paths of length zero may be useful in some situations.
Chachra, V., Ghare, P. M. and Moore, J. M. (1979). Applications of Graph Theory Algorithms. Elvesier North Holland, New York.
# NOT RUN {
getpath(mathgraph(~ 1:3 / 3:5), 1, 5) # returns a path
getpath(mathgraph(~ 1:3 / 3:5), 1, 4) # no path, returns NULL
getpath(mathgraph(~ 1:3 / 3:5), 1, 1) # returns mathgraph()
# }
Run the code above in your browser using DataLab