[igraph] bug in get.all.shortest.paths?

[Laurin Müller]

Hi,

i am using the get.all.shortest.paths method but I think it does not
work correct with graphs where every vertex has the same degree:

with this graph (tree) it works fine:


library(igraph)
library(graph)
library(Rgraphviz)
g = new("graphNEL")
 # add nodes
   g = addNode("1",g)
   g = addNode("2",g)
   g = addNode("3",g)
   g = addNode("4",g)
   g = addNode("5",g)
   g = addNode("6",g)
   g = addNode("7",g)
 # add edges
   g = addEdge("1","2",g,1)
   g = addEdge("2","3",g,1)
   g = addEdge("3","4",g,1)
   g = addEdge("4","5",g,1)
   g = addEdge("5","6",g,1)
   g = addEdge("2","7",g,1)
 # return graphNEL
plot(g)
ig <- igraph.from.graphNEL(g)
get.all.shortest.paths(ig,from=0)

but for this graph (a "ring") where every node has the same degree:

g = new("graphNEL")
 # add nodes
   g = addNode("1",g)
   g = addNode("2",g)
   g = addNode("3",g)
   g = addNode("4",g)
   g = addNode("5",g)
   g = addNode("6",g)
   g = addNode("7",g)
# add edges
   g = addEdge("1","2",g,1)
   g = addEdge("2","3",g,1)
   g = addEdge("3","4",g,1)
   g = addEdge("4","5",g,1)
   g = addEdge("5","6",g,1)
   g = addEdge("6","7",g,1)
   g = addEdge("7","1",g,1)

plot(g)
ig <- igraph.from.graphNEL(g)
get.all.shortest.paths(ig,from=0)

i get follwoing result:
[[1]]
[1] 0

[[2]]
[1] 0 1

[[3]]
[1] 0 1 6

aren't there some paths missing.

get.all.shortest.paths(ig,from=3)

results in:
[[1]]
[1] 3

there should be similar results for all nodes because it is a "ring"
structure.

the result should be something like this:
0
0 1
0 1 2
0 1 2 3
0 6 5 4
0 6 5
0 6

or am I wrong?

hope you can help me,
best
Laurin