def test_balls_difference():
radius = 1.0
displacement = 0.5
s0 = pygalmesh.Ball([displacement, 0, 0], radius)
s1 = pygalmesh.Ball([-displacement, 0, 0], radius)
u = pygalmesh.Difference(s0, s1)
a = numpy.sqrt(radius**2 - displacement**2)
edge_size = 0.15
n = int(2 * numpy.pi * a / edge_size)
circ = [[
0.0, a * numpy.cos(i * 2 * numpy.pi / n),
a * numpy.sin(i * 2 * numpy.pi / n)
] for i in range(n)]
circ.append(circ[0])
pygalmesh.generate_mesh(
u,
"out.mesh",
feature_edges=[circ],
cell_size=0.15,
edge_size=edge_size,
facet_angle=25,
facet_size=0.15,
cell_radius_edge_ratio=2.0,
verbose=False,
)
mesh = meshio.read("out.mesh")
tol = 0.02
assert abs(max(mesh.points[:, 0]) - (radius + displacement)) < tol
assert abs(min(mesh.points[:, 0]) - 0.0) < tol
assert abs(max(mesh.points[:, 1]) - radius) < tol
assert abs(min(mesh.points[:, 1]) + radius) < tol
assert abs(max(mesh.points[:, 2]) - radius) < tol
assert abs(min(mesh.points[:, 2]) + radius) < tol
vol = sum(compute_volumes(mesh.points, mesh.cells["tetra"]))
h = radius - displacement
ref_vol = 4.0 / 3.0 * numpy.pi * radius**3 - 2 * h * numpy.pi / 6.0 * (
3 * a**2 + h**2)
assert abs(vol - ref_vol) < 0.05
return
def l_shape_3d(h):
b0 = pygalmesh.Cuboid([-1.0, -1.0, -1.0], [1.0, 1.0, 1.0])
b1 = pygalmesh.Cuboid([0.0, 0.0, 0.0], [1.1, 1.1, 1.1])
u = pygalmesh.Difference(b0, b1)
mesh = pygalmesh.generate_mesh(
u,
max_edge_size_at_feature_edges=h,
max_cell_circumradius=h,
verbose=False,
# TODO sharpen the intersection edges and avoid
# [1] 591479 segmentation fault (core dumped) python3 pygalmesh_examples.py
# feature_edges=[
# [[1.0, 0.0, z] for z in numpy.linspace(0.0, 1.0, int(1.0 / h))]
# ]
)
mesh.remove_lower_dimensional_cells()
mesh.remove_orphaned_nodes()
return mesh.points, mesh.get_cells_type("tetra")