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# Copyright (C) 2021 Jørgen S. Dokken and Garth N. Wells
#
# This file is part of DOLFINx (https://www.fenicsproject.org)
#
# SPDX-License-Identifier: LGPL-3.0-or-later
import math
from mpi4py import MPI
import numpy as np
import pytest
import dolfinx
from dolfinx import cpp as _cpp
from dolfinx.mesh import GhostMode, create_unit_square
def test_sub_index_map():
comm = MPI.COMM_WORLD
my_rank = comm.rank
# Create index map with one ghost from each other process
n = 7
assert comm.size < n + 1
map_local_size = math.factorial(n)
# The ghosts added are the ith ghost from the ith process relative
# to the current rank, i.e. rank 0 contains the first index of rank
# 2, second of rank 3 etc. rank 1 contains the first index of rank
# 0, the second of rank 2 etc.
# Ghost one index from from every other rank
dest_ranks = np.delete(np.arange(0, comm.size, dtype=np.int32), my_rank)
map_ghosts = np.array(
[map_local_size * dest_ranks[r] + r % map_local_size for r in range(len(dest_ranks))],
dtype=np.int64,
)
src_ranks = dest_ranks
# Create index map
map = dolfinx.common.IndexMap(
comm, map_local_size, [dest_ranks, src_ranks], map_ghosts, src_ranks
)
assert map.size_global == map_local_size * comm.size
# Build list for each rank of the first (myrank + myrank % 2) local
# indices
submap_local_size = [int(rank + rank % 2) for rank in range(comm.size)]
local_indices = [
np.arange(submap_local_size[rank], dtype=np.int32) for rank in range(comm.size)
]
# Create sub index map and a map from the ghost position in new map
# to the position in old map
submap, submap_to_map = _cpp.common.create_sub_index_map(map, local_indices[my_rank], False)
ghosts_pos_sub = submap_to_map[map_local_size:] - map_local_size
# Check local and global sizes
assert submap.size_local == submap_local_size[my_rank]
assert submap.size_global == sum([rank + rank % 2 for rank in range(comm.size)])
# Check that first rank has no elements
if comm.rank == 0:
assert submap.size_local == 0
# Check that rank on sub-process ghosts is the same as the parent
# map
owners = map.owners
assert (dest_ranks == owners).all()
subowners = submap.owners
assert (owners[ghosts_pos_sub] == subowners).all()
def test_sub_index_map_ghost_mode_none():
n = 3
mesh = create_unit_square(MPI.COMM_WORLD, n, n, ghost_mode=GhostMode.none)
tdim = mesh.topology.dim
map = mesh.topology.index_map(tdim)
submap_indices = np.arange(0, min(2, map.size_local), dtype=np.int32)
_cpp.common.create_sub_index_map(map, submap_indices, False)
def test_index_map_ghost_lifetime():
"""Test lifetime management of arrays."""
# Create index map with one ghost from each other process. The
# ghosts added are the ith ghost from the ith process relative to
# the current rank, i.e. rank 0 contains the first index of rank 2,
# second of rank 3 etc. rank 1 contains the first index of rank 0,
# the second of rank 2 etc. Ghost one index from from every other
# rank
comm = MPI.COMM_WORLD
n = 7
assert comm.size < n + 1
local_size = math.factorial(n)
dest = np.delete(np.arange(0, comm.size, dtype=np.int32), comm.rank)
map_ghosts = np.array(
[local_size * dest[r] + r % local_size for r in range(len(dest))], dtype=np.int64
)
src = dest
map = dolfinx.common.IndexMap(comm, local_size, [dest, src], map_ghosts, src)
assert map.size_global == local_size * comm.size
# Test global to local map
global_indices = np.arange(map.size_global, dtype=np.int64)
local_indices = map.global_to_local(global_indices)
for i, ghost in enumerate(map_ghosts):
assert local_indices[ghost] == local_size + i
# Create marker for all indices that are on process (local or ghost)
on_process = np.zeros(map.size_global, dtype=bool)
on_process[map.local_range[0] : map.local_range[1]] = True
on_process[map.ghosts] = True
assert (local_indices[on_process] >= 0).all()
assert np.allclose(local_indices[np.invert(on_process)], -1)
# Test lifetime management
ghosts = map.ghosts
assert np.array_equal(ghosts, map_ghosts)
del map
assert np.array_equal(ghosts, map_ghosts)
# TODO: Add test for case where more than one two process shares an index
# whose owner changes in the submap
def test_create_submap_owner_change():
"""Test create_sub_index_map where the ownership of indices is not
preserved in the submap. The diagram illustrates the case with four
processes. Original map numbering and connectivity (G indicates a ghost
index):
Global Rank 0 Rank 1 Rank 2 Rank 3
1 - 0 1 - 0
| / | | / |
3 - 2 3G - 2 0 - 2G
| / | | / |
5 - 4 3G - 1 0 - 2G
| / | | / |
7 - 6 3G - 1 0 - 3G
| / | | / |
9 - 8 2 - 1
We now create a submap of the "upper triangular" parts to
get the following:
Global Rank 0 Rank 1 Rank 2 Rank 3
1 - 0 1 - 0
| / | /
2 - 3 2G 0 - 1
| / | /
4 - 5 2G 0 - 1
| / | /
6 - 8 2G 0 - 2
| / | /
7 1
"""
comm = MPI.COMM_WORLD
if comm.size == 1:
return
if comm.rank == 0:
local_size = 3
ghosts = np.array([local_size], dtype=np.int64)
owners = np.array([1], dtype=np.int32)
submap_indices = np.array([0, 1, 3], dtype=np.int32)
elif comm.rank == comm.size - 1:
local_size = 3
ghosts = np.array([2 * comm.rank], dtype=np.int64)
owners = np.array([comm.rank - 1], dtype=np.int32)
submap_indices = np.array([0, 3, 2], dtype=np.int32)
else:
local_size = 2
ghosts = np.array([2 * comm.rank, 2 * comm.rank + 3], dtype=np.int64)
owners = np.array([comm.rank - 1, comm.rank + 1], dtype=np.int32)
submap_indices = np.array([0, 2, 3], dtype=np.int32)
imap = dolfinx.common.IndexMap(comm, local_size, ghosts, owners, 1)
sub_imap, sub_imap_to_imap = _cpp.common.create_sub_index_map(imap, submap_indices, True)
if comm.rank == 0:
assert sub_imap.size_local == 2
assert np.array_equal(sub_imap.ghosts, [2])
assert np.array_equal(sub_imap.owners, [comm.rank + 1])
assert np.array_equal(sub_imap_to_imap, [0, 1, 3])
elif comm.rank == comm.size - 1:
assert sub_imap.size_local == 3
assert np.array_equal(sub_imap.ghosts, [])
assert np.array_equal(sub_imap.owners, [])
assert np.array_equal(sub_imap_to_imap, [0, 2, 3])
else:
assert sub_imap.size_local == 2
assert np.array_equal(sub_imap.ghosts, [2 * (comm.rank + 1)])
assert np.array_equal(sub_imap.owners, [comm.rank + 1])
assert np.array_equal(sub_imap_to_imap, [0, 2, 3])
global_indices = sub_imap.local_to_global(
np.arange(sub_imap.size_local + sub_imap.num_ghosts, dtype=np.int32)
)
assert np.array_equal(global_indices, np.arange(comm.rank * 2, comm.rank * 2 + 3))
def test_sub_index_map_multiple_possible_owners():
"""Check that creating a submap doesn't crash when an index need to change owner and
there are multiple possible new owners"""
comm = MPI.COMM_WORLD
if comm.size < 3:
pytest.skip("Test requires 3 or more processes")
# Create an index map with an index on process 2 that is ghosted by processes 0 and 1
if comm.rank == 0:
local_size = 1
ghosts = np.array([2], dtype=np.int64)
owners = np.array([2], dtype=np.int32)
submap_indices = np.array([0, 1], dtype=np.int32)
# NOTE: This assumes that the lowest ranking process takes ownership of the index
# in the submap
submap_size_local_expected = 2
submap_num_ghosts_expected = 0
elif comm.rank == 1:
local_size = 1
ghosts = np.array([2], dtype=np.int64)
owners = np.array([2], dtype=np.int32)
submap_indices = np.array([0, 1], dtype=np.int32)
submap_size_local_expected = 1
submap_num_ghosts_expected = 1
elif comm.rank == 2:
local_size = 1
ghosts = np.array([], dtype=np.int64)
owners = np.array([], dtype=np.int32)
submap_indices = np.array([], dtype=np.int32)
submap_size_local_expected = 0
submap_num_ghosts_expected = 0
else:
local_size = 0
ghosts = np.array([], dtype=np.int64)
owners = np.array([], dtype=np.int32)
submap_indices = np.array([], dtype=np.int32)
submap_size_local_expected = 0
submap_num_ghosts_expected = 0
imap = dolfinx.common.IndexMap(comm, local_size, ghosts, owners, 0)
# Create a submap where both processes 0 and 1 include the index on process 2,
# but process 2 does not include it
sub_imap = _cpp.common.create_sub_index_map(imap, submap_indices, True)[0]
assert sub_imap.size_global == 3
assert sub_imap.size_local == submap_size_local_expected
assert sub_imap.num_ghosts == submap_num_ghosts_expected
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