Hello (again), it just occurred to me (why not before?) that the error message "matrices not conformable for operation" could be made more useful by immediately including the dimensions of the matrices involved. Example: ? matrix test1 = zeros(2,2) ? matrix test2 = ones(3,3) ? matrix test3 = test1 * test2 Matrizen nicht passend bei Operation It wouldn't be too difficult for gretl to amend this message with "2 x 2 and 3 x 3", right? I think this would be very convenient for script writers, because currently we have to write some debugging printf statements in the right places, re-run the script to get the same information, and later delete the printf-s. thanks, sven