Reported by eike on 2011-06-13 15:07 UTC
Change the interface of bdalg.feedback to that of Matlab's feedback function. The current interface is too cumbersome for MIMO models.

The function should react differently whether it has 2, 3, 4, or 5 arguments:

Implies: both systems may be MIMO or SISO; sys1.inputs == sys2.outputs; sys2.inputs == sys1.outputs
feedback(sys1, sys2)
feedback(sys1, sys2, sign)

Implies: sys1: MIMO; sys2: SISO
feedback(sys1, sys2, sys1_in, sys1_out)
feedback(sys1, sys2, sys1_in, sys1_out, sign)

See:
http://www.mathworks.com/help/toolbox/control/ref/feedback.html

The implementation should be no big intellectual endeavor, because a general implementation of feedback for MIMO systems already exists.
It just requires work, and a little design (maybe introduce a function siso2mimo).
The current implementation covers the case of 2, and 3 arguments.