Hi, I wonder, why I can use only pinv. When I use pinv2 to compute the pseudo-inverse of Z I get the following message Z [[ 3.21699578 1.47577916 -3.05873705] [-1.54994823 3.24940826 2.79976045] [-4.241916 -2.41995866 -1.40655762] [ 2.81641276 -3.34681092 2.10674418] [-0.15888331 0.24404542 -0.20391515]] Pseudo-inverse of Z using lstsq [[ 0.07522953 -0.03500246 -0.11248811 0.08017751 -0.00476346] [ 0.05183121 0.10614625 -0.07713549 -0.11648354 0.00853543] [-0.12411384 0.11106407 -0.06726151 0.10105305 -0.00939367]] Pseudo-inverse of Z using svd Traceback (most recent call last): File "huadai.py", line 101, in ? h4 = linalg.pinv2(Z) File "/usr/local/lib/python2.1/site-packages/scipy/linalg/basic.py", line 327, in pinv2 return dot(tran(conj(vh)),tran(conj(u))*s[:,NewAxis]) ValueError: frames are not aligned Any suggestion ? Nils