Oh yes, that was silly! Thanks Martin - I didn't know you were on this list. cheers --cjc ________________________________ From: firedrake-bounces@imperial.ac.uk [firedrake-bounces@imperial.ac.uk] on behalf of Martin Sandve Alnæs [martinal@simula.no] Sent: 12 June 2014 08:43 To: firedrake Subject: Re: [firedrake] trying to set up nonlinear problem It's in the solve: #w0 = Function(W) # drop this #solve(a == 0, w0, bcs=bcs) solve(a == 0, w, bcs=bcs) # use the Function that is used in 'a' Martin On 12 June 2014 08:57, Cotter, Colin J <colin.cotter@imperial.ac.uk<mailto:colin.cotter@imperial.ac.uk>> wrote: Dear Firedrakers, When I run the following script: https://gist.github.com/anonymous/32edd8c9c1614c1e2b67 I get: ufl.log.UFLException: All terms in form must have same rank. This is probably because I don't know how to set up nonlinear problems properly. Can anyone spot what is wrong? cheers --cjc _______________________________________________ firedrake mailing list firedrake@imperial.ac.uk<mailto:firedrake@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/firedrake