statsmodels/statsmodels — pull request #486 by tshauck (2012-09-29 23:26:46+00:00)
Title: Address issue #322 that acovf doesn't work w/ pandas Series

A workaround for the issue that when you pass a series to np.correlate it returns half of the series leaving the other half as `%s`s.

Uses the fact that np.correlate returns a symmetric array. So reversing it doesn't effect the situation when a numpy array is passed, but it properly aligns the series for the index call coming later.