def unit_mesh(ht, hx):
editor = MeshEditor()
mesh = Mesh()
editor.open(mesh, "triangle", 2, 2)
editor.init_vertices(7)
editor.add_vertex(0, np.array([0.0, 0.0]))
editor.add_vertex(1, np.array([ht / 2.0, 0.0]))
editor.add_vertex(2, np.array([0.0, hx / 2.0]))
editor.add_vertex(3, np.array([ht / 2.0, hx / 2.0]))
editor.add_vertex(4, np.array([ht, hx / 2.0]))
editor.add_vertex(5, np.array([ht / 2.0, hx]))
editor.add_vertex(6, np.array([ht, hx]))
editor.init_cells(6)
editor.add_cell(0, np.array([0, 1, 3], dtype=np.uintp))
editor.add_cell(1, np.array([0, 2, 3], dtype=np.uintp))
editor.add_cell(2, np.array([1, 3, 4], dtype=np.uintp))
editor.add_cell(3, np.array([2, 3, 5], dtype=np.uintp))
editor.add_cell(4, np.array([3, 4, 6], dtype=np.uintp))
editor.add_cell(5, np.array([3, 5, 6], dtype=np.uintp))
editor.close()
mesh.order()
return mesh
def gather_mesh(mesh):
"""Gather a local copy of a distributed mesh"""
# comm = MPI.COMM_WORLD
if mesh in gather_mesh_cache:
logGATHER('gather_mesh cache hit')
return gather_mesh_cache[mesh]
comm = mesh.mpi_comm()
size = comm.size
if size == 1:
gather_mesh_cache[mesh] = mesh
return (mesh) # sequential: nothing to do
dim = mesh.geometry().dim()
topology = mesh.topology()
logGATHER('topology.global_indices(0)', topology.global_indices(0))
logGATHER('topology.size(0)', topology.size(0))
#
# To define a mesh, we need two things: a list of all the
# vertices, each with an index and coordinates, and a list of all
# cells, each specified by a list of vertices.
#
vcoord = mesh.coordinates()
vcoords = gather_array(vcoord, comm) # vertexes from all processes
vindex = topology.global_indices(0)
vindexes = gather_array(vindex, comm) # global vertex indexes
try:
gnv = topology.size_global(0)
except AttributeError:
gnv = np.max(vindexes) + 1
logGATHER('gnv', gnv)
gvcs = np.zeros((gnv, dim), dtype=vcoords.dtype)
for v, vc in enumerate(vcoords): # coords indexed by global indices
gvcs[vindexes[v], :] = vc
logGATHER('gvcs', gvcs)
#
# We now have in gvcs a list of global vertex coordinates. (The
# indices are just 0...len(gvcs)-1.) Now for the cells:
#
nc = mesh.num_cells()
logGATHER('nc', nc)
total = comm.allreduce(nc)
logGATHER('total', total)
cell = np.zeros(nc * (dim + 1), dtype=int)
cell[:] = vindex[mesh.cells().flatten()] # vindex to get global indices
logGATHER('cell', cell)
cells = gather_array(cell, comm)
cells = cells.reshape(-1, dim + 1)
logGATHER('cells', cells)
cindex = topology.global_indices(dim)
logGATHER('cindex', cindex)
cindexes = gather_array(cindex, comm)
logGATHER('cindexes', cindexes)
try:
gnc = topology.size_global(dim)
except AttributeError:
gnc = np.max(cindexes) + 1
logGATHER('gnc', gnc)
gcells = np.zeros((gnc, dim + 1), dtype=int)
for v, cell in enumerate(cells):
gcells[cindexes[v], :] = cell
logGATHER('gcells', gcells)
#
# Now use this collected info to construct a mesh
#
try:
scomm = fe.mpi_comm_self()
except AttributeError:
scomm = MPI.COMM_SELF
mesh = Mesh(scomm) # new mesh is sequential
logGATHER('scomm', scomm)
logGATHER('MPI.COMM_SELF', MPI.COMM_SELF)
# if comm.rank == 0:
if True: # construct a mesh in all processes
editor = MeshEditor()
editor.open(mesh, str(cellShapes[dim - 1]), dim, dim)
editor.init_vertices_global(len(gvcs), len(gvcs))
editor.init_cells_global(len(gcells), len(gcells))
for v, vc in enumerate(gvcs):
editor.add_vertex_global(v, v, vc)
for c, cell in enumerate(gcells):
logGATHER('c, cell', c, cell)
editor.add_cell(c, cell)
mesh.order()
logGATHER('mesh.mpi_comm()', mesh.mpi_comm())
logGATHER('mesh.mpi_comm().size', mesh.mpi_comm().size)
gather_mesh_cache[mesh] = mesh
logGATHER('caching gathered mesh')
return (mesh)
