Dear all, I am defining a mixed system as follows: V = FunctionSpace(mesh, "CG", 1) V_R = FunctionSpace(mesh, "R", 0) W = V * V * V * V_R * V_R * V_R and some of the functions defined are: Z0 = Function(V_R) w = Function(W) phi, eta, mu, Z1, W1, I = split(w) After defining and solving some solvers etc, I do the following assignment but run into a “Mismatching function spaces” error: Z0.assign(Z1) Variable Z1 is solved in a mixed system and I want to assign it to Z0, which belongs to space V_R. Shouldn’t the assignment line above work? Why am I getting the error? Thank you, Anna. On 19 Feb 2017, at 23:09, Anna Kalogirou <a.kalogirou@leeds.ac.uk<mailto:a.kalogirou@leeds.ac.uk>> wrote: Dear all, I am trying to solve a set of PDEs and ODEs together as a mixed system. The ODE variables only depend on time, so I define them as functions from the real function space R. First question: Is this a correct approach? Second question: I am running into a “Mismatching function spaces” error; can someone please take a look at my code (found here<https://bitbucket.org/annakalog/buoy2d/src/957e88739223e11d84826c76923a9b07d2ee58a0/Mixed%20system/Alternative-approach-with-scalars/?at=master>) and let me know what I’m doing wrong? The error arises when the value of one of the mixed-system variables is assigned to another variable which belongs to the same function space. [I remember having the same issue some time ago, but I thought that it was fixed.] Thank you. Best, Anna. _______________________________________________ firedrake mailing list firedrake@imperial.ac.uk<mailto:firedrake@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/firedrake