I read in the manual that with matrix addition and subtraction scalars or 1x1 matrices are expanded to be conformable with the other argument, e.g. matrix jan=1+ones(3,1) works and results in a 3x1 matrix. Adding the next command also works as expected: matrix jan=ones(3,1)+jan'jan However, reversing the command results in an error: matrix jan=jan'jan + ones(3,1) Matrices not conformable for operation Is this normal behaviour and am I missing something, or is this a bug? I'm using Gretl 1.9.5cvs built 2011-04-24 on Mac OS X 10.6.8 Thanks Jan Annaert UNIVERSITEITANTWERPEN | Faculty of Applied Economics (TEW) | Dept. Accounting & Finance Room S.B.335 | Prinsstraat 13 | B-2000 Antwerp | Belgium Phone +32 32654163 |Fax +32 32654064 http://www.ua.ac.be/jan.annaert http://ssrn.com/author=143473