pydata/pandas — pull request #6650 by agijsberts (2014-03-15 21:17:46+00:00)
Title: PERF: Speed up DatetimeConverter by using Matplotlib's epoch2num when possible...

This fixes the performance bottleneck described in #6636 by using the vectorized epoch2num for DataIndex arrays. The included test ensures that the DatetimeConverter produces the same results as the Matplotlib's date2num for individual Timestamp objects as well as DatetimeIndex array objects.