Error when using project in mantle convection demo

[ddundo]

Using transfer_method="project" (default) in the mantle convection demo raises an error:

Traceback (most recent call last):
  File "/home/firedrake/firedrake/src/goalie/demos/mantle_convection.py", line 185, in <module>
    solutions = mesh_seq.solve_forward()
                ^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/goalie/goalie/mesh_seq.py", line 574, in solve_forward
    next(solver_gen)
  File "/home/firedrake/firedrake/src/goalie/goalie/mesh_seq.py", line 512, in _solve_forward
    field: self._transfer(
           ^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/goalie/goalie/mesh_seq.py", line 313, in _transfer
    return transfer(source, target_space, self._transfer_method, **transfer_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/animate/animate/interpolation.py", line 74, in transfer
    return _transfer_forward(source, target, transfer_method, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/animate/animate/interpolation.py", line 188, in _transfer_forward
    t.project(s, **kwargs)
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/adjoint_utils/function.py", line 47, in wrapper
    output = project(self, b, *args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/firedrake/firedrake/function.py", line 363, in project
    return projection.project(b, self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/adjoint_utils/projection.py", line 34, in wrapper
    output = project(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 113, in project
    ).project()
      ^^^^^^^^^
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 223, in project
    self.apply_massinv(self.target, self.rhs)
                                    ^^^^^^^^
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 286, in rhs
    self.mixed_mass.mult(u, v)
    ^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/functools.py", line 995, in __get__
    val = self.func(instance)
          ^^^^^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 280, in mixed_mass
    return assemble_mixed_mass_matrix(self.source.function_space(),
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/supermeshing.py", line 192, in assemble_mixed_mass_matrix
    V_S_A = FunctionSpace(reference_mesh, V_A.ufl_element())
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/functionspace.py", line 104, in FunctionSpace
    element = make_scalar_element(mesh, family, degree, vfamily, vdegree, variant)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "petsc4py/PETSc/Log.pyx", line 188, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 189, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/functionspace.py", line 56, in make_scalar_element
    return family.reconstruct(cell=cell)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/FInAT/finat/ufl/finiteelement.py", line 214, in reconstruct
    return FiniteElement(family, cell, degree, quad_scheme=quad_scheme, variant=variant)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/FInAT/finat/ufl/finiteelement.py", line 145, in __init__
    ) = canonical_element_description(family, cell, degree, form_degree)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/firedrake/firedrake/src/FInAT/finat/ufl/elementlist.py", line 466, in canonical_element_description
    raise ValueError(f"Cellname '{cellname}' invalid for '{family}' finite element.")
ValueError: Cellname 'triangle' invalid for 'Q' finite element.

[ddundo]

The cause is that we are using a quadrilateral mesh UnitSquareMesh(32, 32, quadrilateral=True). Since I'm not familiar with the theory, I don't know if this is actually a bug - but either way, it's not on our side. So I'll just open a PR that doesn't use a quadrilateral mesh

@stephankramer maybe this is of interest to you since the code is from your paper? :)