statsmodels/statsmodels — pull request #1424 by jseabold (2014-02-24 04:50:55+00:00)
Title: ENH: Consistent results for transform_slices

Right now the transform_dataframe, transform_array, and transform_slices are a bit confused vs. transform / apply in pandas. Our transform_ functions can do both transform and apply. Now, the results are always concatenated such that they'll be 2D. *Should* handle single group, panel, and multiple groups now.