I repeated the exercise from yesterday, this time driving the butterfly mode [+1 1 1 +1] and adding the tuned PIT and YAW vectors from yesterday to it to minimize appearance in the Oplev error signals.
The measured output matrix is , where rows are the coils in the order [UL,UR,LL,LR] and columns are the DOFs in the order [POS,PIT,YAW,Butterfly]. The conclusions from my previous elog still hold though  the orthogonality between PIT and YAW is poor, so this output matrix cannot be realized by a simple gain scaling of the coil output gains. The "adjustment matrix", i.e. the 4x4 matrix that we must multiply the "ideal" output matrix by to get the measured output matrix has a condition number of 134 (1 is a good condition number, signifies closeness to the identity matrix).
Quote: 
let us have 3 by 4, nevermore
so that the number of columns is no less
and no more
than the number of rows
so that forevermore we live as 4 by 4

