statsmodels/statsmodels — pull request #1699 by josef-pkt (2014-05-27 18:38:44+00:00)
Title: TST/ENH StandardizeTransform, reparameterize TestProbitCG

see #1690 and #1648 for convergence problems in TestProbitCG

This PR add a stateful StandardizeTransform class.
and adjusts the test to use the standardized model to get start_params for the original model.

see #1131 for expanding this to other cases that are difficult to optimize.