RobotLocomotion/drake — pull request #183 by blandry (2014-06-19 06:29:06+00:00)
Title: Fix for gradient with position control enabled

Not ready to merge. The user gradient with respect to the input (the last column of df2) is zero for the user gradients but non-zero for the numerical ones. Do we have a bug in TimeSteppingRigidBodyManipulator? I can look into it I wanted to check I am not missing something conceptually first.