NaN codelength using Regularized ME when all links to a node are zero

[antoneri]

Example: Run with --regularized

# Zacharys karate club
0 1 4
0 2 5
0 3 3
0 4 3
0 5 3
0 6 3
0 7 2
0 8 2
0 10 2
0 11 3
0 12 1
0 13 3
0 17 2
0 19 0
0 21 2
0 31 2
1 2 6
1 3 3
1 7 4
1 13 5
1 17 1
1 19 0
1 21 2
1 30 2
2 3 3
2 7 4
2 8 5
2 9 1
2 13 3
2 27 2
2 28 2
2 32 2
3 7 3
3 12 3
3 13 3
4 6 2
4 10 3
5 6 5
5 10 3
5 16 3
6 16 3
8 30 3
8 32 3
8 33 4
9 33 2
13 33 3
14 32 3
14 33 2
15 32 3
15 33 4
18 32 1
18 33 2
19 33 0
20 32 3
20 33 1
22 32 2
22 33 3
23 25 5
23 27 4
23 29 3
23 32 5
23 33 4
24 25 2
24 27 3
24 31 2
25 31 7
26 29 4
26 33 2
27 33 4
28 31 2
28 33 2
29 32 4
29 33 2
30 32 3
30 33 3
31 32 4
31 33 4
32 33 5