| getpath {mathgraph} | R Documentation |
Returns a path, if it exists, from the start to the end.
getpath(x, start, end, ...) getpath.mathgraph(x, start, end, ...)
x |
an object representing a mathematical graph. |
start |
character string or integer giving the starting node. |
end |
character string or integer giving the ending node. |
... |
generic arguments. |
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.
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.
S Poetry, Patrick J. Burns, Section 13.3
Nick Efthymiou
Chachra, V., Ghare, P. M. and Moore, J. M. (1979). Applications of Graph Theory Algorithms. Elvesier North Holland, New York.
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()