Dear SPM users,
I have a question concerning the least squares fit performed in the
spm_realign.m by the parameter dectection loop:
The least squares solution for [-dXdQ Y] * q0 = X is here calculated by
q0 =[-dXdQ Y]\X .
Wouldn't it be better to use
q0 = pinv( [-dXdQ Y] ) * X
instead, because this expression minimizes || [-dXdQ Y] * q0 - X ||,
whereas the acutally used expression generates the solution with the fewest
possible nonzero components ?
Thanks in advance
Stefan Thesen
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|