ENH: Improve test in preparation for performance testing

The performance testing that is to follow may change the results slightly
due to numerical stability of the order of accumulations.

This patch introduces more verbose debugging statements to ease
the processes of debugging and verifying that the new optimized
version of the code continues to produce meaningful results.

Initialize identity transform with member function rather than explicit
error prone parameter setting.

Change-Id: Ife034c472f41de10126cecfa6be5213b7c2fa5db
Merge topic 'PrepareMattesForPerformanceTesting'

40342d65 ENH: Improve test in preparation for performance testing