Hi All, Sorry to post a question in the chat and then disappear - I'd lost track of time and needed to dash home. Anyway, I've copied and pasted my question... 18:26 < jemma> I have pulled some code Colin added this morning 18:27 < jemma> and it doesn't work - although Colin was quite happily running it before he went to watch tennis 18:27 < jemma> can anyone see why there'd be a problem with this: 18:27 < jemma> u = project(Expression(("1.0 + sin(pi*(x[0]-t))*sin(pi*x[1])*cos(pi*t/T0)","cos(pi*(x[0]-t))*cos(pi*x[1])*cos(pi*t/T0)")t=t,T0=T0),V1) 18:28 < jemma> where V1 comes from: 18:28 < jemma> V1_v = OuterProductElement(IUh1, IUv0) 18:28 < jemma> V1_h = OuterProductElement(IUh0, IUv1) 18:28 < jemma> V1_elt = HDiv(V1_v) + HDiv(V1_h) 18:28 < jemma> V1 = FunctionSpace(mesh,V1_elt) 18:28 < jemma> t and T0 are defined 18:29 < jemma> maybe I'm missing a ufl/pyop2/something update - I haven't updated in a while... When I run the code won't even compile: pyop2.exceptions.CompilationError: Unable to compile code I've attached the log and err files. The problem seems to be the variables t and T0 in the expression - although they are defined in previous lines: t = 0.0 T0 = 1.0 The script I'm trying to run is at: https://bitbucket.org/colinjcotter/vertical-tests/src/c1a2a565912564897fdbec... Thanks! Jemma