#Credits: http://stackoverflow.com/questions/29314795/python-igraph-get-all-possible-paths-is-a-directed-graph

def find_all_paths(graph, start, end, mode = 'OUT', maxlen = None):

def find_all_paths_aux(adjlist, start, end, path, maxlen = None):

path = path + [start]

if start == end:

return [path]

paths = []

if maxlen is None or len(path) <= maxlen:

for node in adjlist[start] - set(path):

paths.extend(find_all_paths_aux(adjlist, node, end, path, maxlen))

return paths

adjlist = [set(graph.neighbors(node, mode = mode)) \

for node in xrange(graph.vcount())]

all_paths = []

start = start if type(start) is list else [start]

end = end if type(end) is list else [end]

for s in start:

for e in end:

all_paths.extend(find_all_paths_aux(adjlist, s, e, [], maxlen))

return all_paths