On Sat, 22 Mar 2008, Nadav Horesh apparently wrote: >>>> A*v ... > ValueError: objects are not aligned This is just how I want matrices to act! If A is m׳n, then v should be n׳1 for A*v to be defined. Anything else is trouble waiting to happen. But it seems that Charles's proposal would make life more convenient for you... Cheers, Alan Isaac