statsmodels/statsmodels — pull request #1583 by jseabold (2014-04-09 14:46:12+00:00)
Title: BUG: For ARMA(0,0) ensure 1d bse and fix summary.

Roots, etc. doesn't exist for ARMA(0,0) so `summary` failed. `summary2` failed because the shape of the confidence interval in the 1 params case ended up being (1, 2, 1) because bse itself was 2d. Fixed both of these.