Cythonized expected_mutual_information disagrees with former version

[jnothman]

This SO post appears to highlight a long-standing bug introduced in 9cf5f00, shortly after expected_mutual_information was rewritten in cython. See #1334

Using the SO poster's data:

import urllib  # py2
import ast
import numpy as np
from sklearn.metrics import cluster
pred = np.array(ast.literal_eval(urllib.urlopen('http://pastebin.com/raw/hJz1M4sf').read()))
true = np.array(ast.literal_eval(urllib.urlopen('http://pastebin.com/raw/9Y5TE6b7').read()))
print(cluster.expected_mutual_information(cluster.contingency_matrix(pred,true), len(pred)))

output prior to 9cf5f00: 0.000307845374016.

output since 9cf5f00: 1.53843820095.

[jnothman]

Huh. Now I can't replicate it. Might not be due to 09714bc; might have been a recompilation problem. EDIT: updated description now that I discovered "dirty fix" in 9cf5f00 was culprit.