BUG: BDM elements cannot be projected on different meshes about firedrake

[colinjcotter]

You can do this by remapping the function to the enclosing DG space and transferring that, then remapping back to BDM.

[zhyxue0]

You can do this by remapping the function to the enclosing DG space and transferring that, then remapping back to BDM.

Thanks. @colinjcotter It works. But there also seemed to be new issues with reading the mesh when running in parallel on multiple cores.

Here is my code:

from firedrake import *


num_refs = 3
Lx = 2 
Ly = 2


mesh_table = []
for i in range(num_refs):

    Nx = 4*2**(i)
    Ny = Nx
    mesh_1 = RectangleMesh(Nx, Ny, Lx, Ly)
    V_1 = VectorFunctionSpace(mesh_1, "DG", 1)
    
    u_1 = Function(V_1)
 
    mesh_table.append(mesh_1)


V_DG = VectorFunctionSpace(mesh_table[0], "DG", 1)
u_2 = project(u_1, V_DG)
    

Here is the report:

Traceback (most recent call last):
  File "/home/text_1.py", line 31, in <module>
Traceback (most recent call last):
  File "/home/text_1.py", line 31, in <module>
    u_2 = project(u_1, V_DG)
  File "petsc4py/PETSc/Log.pyx", line 115, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
    u_2 = project(u_1, V_DG)
  File "petsc4py/PETSc/Log.pyx", line 115, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 116, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 116, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/adjoint/projection.py", line 34, in wrapper
  File "/home/firedrake/firedrake/src/firedrake/firedrake/adjoint/projection.py", line 34, in wrapper
    output = project(*args, **kwargs)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 78, in project
    output = project(*args, **kwargs)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 78, in project
    use_slate_for_inverse=use_slate_for_inverse).project()
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 181, in projecTraceback (most recent call last):
  File "/home/text_1.py", line 19, in <module>
Traceback (most recent call last):
  File "/home/text_1.py", line 19, in <module>
    u_2 = project(u_1, V_DG)
  File "petsc4py/PETSc/Log.pyx", line 115, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
    u_2 = project(u_1, V_DG)
  File "petsc4py/PETSc/Log.pyx", line 115, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 116, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 116, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/adjoint/projection.py", line 34, in wrapper
  File "/home/firedrake/firedrake/src/firedrake/firedrake/adjoint/projection.py", line 34, in wrapper
    output = project(*args, **kwargs)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 78, in project
    output = project(*args, **kwargs)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 78, in project
    use_slate_for_inverse=use_slate_for_inverse).project()
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 181, in project
    use_slate_for_inverse=use_slate_for_inverse).project()
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 181, in project
    self.apply_massinv(self.target, self.rhs)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 240, in rhs
    self.apply_massinv(self.target, self.rhs)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 240, in rhs
    self.mixed_mass.mult(u, v)
  File "/home/firedrake/firedrake/src/PyOP2/pyop2/utils.py", line 62, in __get__
    self.mixed_mass.mult(u, v)
  File "/home/firedrake/firedrake/src/PyOP2/pyop2/utils.py", line 62, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 234, in mixed_mass
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/firedrake/firedrake/src/firedrake/firedrake/projection.py", line 234, in mixed_mass
    return assemble_mixed_mass_matrix(self.source.function_space(),
  File "petsc4py/PETSc/Log.pyx", line 115, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
    return assemble_mixed_mass_matrix(self.source.function_space(),
  File "petsc4py/PETSc/Log.pyx", line 115, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 116, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "petsc4py/PETSc/Log.pyx", line 116, in petsc4py.PETSc.Log.EventDecorator.decorator.wrapped_func
  File "/home/firedrake/firedrake/src/firedrake/firedrake/supermeshing.py", line 97, in assemble_mixed_mass_matrix
  File "/home/firedrake/firedrake/src/firedrake/firedrake/supermeshing.py", line 97, in assemble_mixed_mass_matrix
    intersections = intersection_finder(mesh_A, mesh_B)
  File "firedrake/cython/supermeshimpl.pyx", line 132, in firedrake.cython.supermeshimpl.intersection_finder
    intersections = intersection_finder(mesh_A, mesh_B)
  File "firedrake/cython/supermeshimpl.pyx", line 132, in firedrake.cython.supermeshimpl.intersection_finder
AssertionError: Whoever made mesh_B should explicitly mark mesh_A as having a compatible parallel layout.
application called MPI_Abort(PYOP2_COMM_WORLD, 1) - process 0
AssertionError: Whoever made mesh_B should explicitly mark mesh_A as having a compatible parallel layout.
application called MPI_Abort(PYOP2_COMM_WORLD, 1) - process 1