Comment 2 for bug 404256

Reduced the size of the previous edge list while retaining the exception.
The second graph is the first graph less the last edge.
Strange that the second graph with the worse condition number takes an extra call to eigenvector before ARPACK goes...

g=igraph.Graph([(2, 0), (3, 0), (4, 1), (4, 1), (5, 2), (6, 4), (7, 5), (7, 4), (8, 4), (8, 4), (9, 4), (9, 0), (10, 2), (11, 7), (12, 0), (13, 8), (13, 9), (13, 8), (15, 6), (16, 9), (16, 2), (16, 3), (17, 0), (17, 8), (17, 2), (17, 14), (18, 15), (18, 0), (18, 3), (18, 3), (19, 6), (20, 19), (20, 8), (20, 10), (20, 16), (20, 2), (22, 9), (23, 10), (24, 4), (24, 20), (24, 13), (24, 13), (25, 9), (26, 15), (26, 20), (26, 13), (26, 4), (27, 5), (27, 25), (27, 12), (27, 18), (27, 10), (28, 21), (28, 27), (29, 5), (29, 3), (29, 23), (29, 18), (32, 3), (33, 22), (33, 25), (34, 3), (34, 27), (34, 1), (35, 8), (35, 34), (36, 33), (36, 31), (36, 15), (36, 34), (36, 24), (37, 4), (38, 9), (38, 10), (38, 29), (39, 26), (39, 26), (40, 5), (40, 31), (40, 16), (41, 13), (41, 7), (41, 32), (42, 22), (42, 5), (42, 14), (43, 10), (45, 30), (48, 5), (49, 34), (50, 5), (50, 24), (51, 30), (51, 2), (51, 26), (51, 19), (51, 10), (53, 17), (53, 46), (54, 38), (54, 38), (55, 54), (55, 27), (55, 25), (55, 27), (55, 50), (56, 39), (56, 3), (57, 52)])

cond(A) ~ 4e17
max eig ~ 5.59208777925

ARPACK exception is thrown after 2 calls to community_leading_eigenvector().

g=igraph.Graph([(2, 0), (3, 0), (4, 1), (4, 1), (5, 2), (6, 4), (7, 5), (7, 4), (8, 4), (8, 4), (9, 4), (9, 0), (10, 2), (11, 7), (12, 0), (13, 8), (13, 9), (13, 8), (15, 6), (16, 9), (16, 2), (16, 3), (17, 0), (17, 8), (17, 2), (17, 14), (18, 15), (18, 0), (18, 3), (18, 3), (19, 6), (20, 19), (20, 8), (20, 10), (20, 16), (20, 2), (22, 9), (23, 10), (24, 4), (24, 20), (24, 13), (24, 13), (25, 9), (26, 15), (26, 20), (26, 13), (26, 4), (27, 5), (27, 25), (27, 12), (27, 18), (27, 10), (28, 21), (28, 27), (29, 5), (29, 3), (29, 23), (29, 18), (32, 3), (33, 22), (33, 25), (34, 3), (34, 27), (34, 1), (35, 8), (35, 34), (36, 33), (36, 31), (36, 15), (36, 34), (36, 24), (37, 4), (38, 9), (38, 10), (38, 29), (39, 26), (39, 26), (40, 5), (40, 31), (40, 16), (41, 13), (41, 7), (41, 32), (42, 22), (42, 5), (42, 14), (43, 10), (45, 30), (48, 5), (49, 34), (50, 5), (50, 24), (51, 30), (51, 2), (51, 26), (51, 19), (51, 10), (53, 17), (53, 46), (54, 38), (54, 38), (55, 54), (55, 27), (55, 25), (55, 27), (55, 50), (56, 39), (56, 3)])

cond(A) ~ 3e32
max eig ~ 5.59208777925

ARPACK exception is thrown after 3 calls to community_leading_eigenvector().