def test_compute_position_center_of_mass():
"""
This test is testing compute position center of mass method of Sphere class.
Returns
-------
"""
start = np.random.rand(3)
base_radius = np.random.uniform(1, 10)
density = np.random.uniform(1, 10)
test_sphere = Sphere(start, base_radius, density)
correct_position = start
test_position = test_sphere.compute_position_center_of_mass()
assert_allclose(correct_position, test_position, atol=Tolerance.atol())
def test_sphere_compute_internal_forces_and_torques():
"""
This is test is checking the validity of _compute_internal_forces_and_torques function.
Returns
-------
"""
start = np.random.rand(3)
base_radius = np.random.uniform(1, 10)
density = np.random.uniform(1, 10)
test_sphere = Sphere(start, base_radius, density)
test_sphere._compute_internal_forces_and_torques(time=0)
assert_allclose(np.zeros((3, 1)),
test_sphere.internal_forces,
atol=Tolerance.atol())
assert_allclose(np.zeros((3, 1)),
test_sphere.internal_torques,
atol=Tolerance.atol())
def test_compute_translational_energy():
"""
This test is testing compute translational energy function.
Returns
-------
"""
start = np.random.rand(3)
base_radius = np.random.uniform(1, 10)
volume = 4.0 / 3.0 * np.pi * base_radius ** 3
density = np.random.uniform(1, 10)
mass = density * volume
test_sphere = Sphere(start, base_radius, density)
speed = np.random.randn()
test_sphere.velocity_collection[2] = speed
correct_energy = 0.5 * mass * speed ** 2
test_energy = test_sphere.compute_translational_energy()
assert_allclose(correct_energy, test_energy, atol=Tolerance.atol())
def test_cylinder_update_accelerations():
"""
This test is testing the update acceleration method of Sphere class.
Returns
-------
"""
start = np.random.rand(3)
base_radius = np.random.uniform(1, 10)
volume = 4.0 / 3.0 * np.pi * base_radius**3
density = np.random.uniform(1, 10)
mass = density * volume
test_sphere = Sphere(start, base_radius, density)
inv_mass_second_moment_of_inertia = (
test_sphere.inv_mass_second_moment_of_inertia.reshape(3, 3))
external_forces = np.random.randn(3).reshape(3, 1)
external_torques = np.random.randn(3).reshape(3, 1)
correct_acceleration = external_forces / mass
correct_alpha = inv_mass_second_moment_of_inertia @ external_torques.reshape(
3)
correct_alpha = correct_alpha.reshape(3, 1)
test_sphere.external_forces[:] = external_forces
test_sphere.external_torques[:] = external_torques
test_sphere.update_accelerations(time=0)
assert_allclose(correct_acceleration,
test_sphere.acceleration_collection,
atol=Tolerance.atol())
assert_allclose(correct_alpha,
test_sphere.alpha_collection,
atol=Tolerance.atol())
def test_sphere_initialization():
"""
This test case is for testing initialization of rigid sphere and it checks the
validity of the members of sphere class.
Returns
-------
"""
# setting up test params
start = np.random.rand(3)
direction = np.array([0.0, 0.0, 1.0]).reshape(3, 1)
normal = np.array([1.0, 0.0, 0.0]).reshape(3, 1)
binormal = np.cross(direction[..., 0], normal[..., 0]).reshape(3, 1)
base_radius = np.random.uniform(1, 10)
volume = 4.0 / 3.0 * np.pi * base_radius ** 3
density = np.random.uniform(1, 10)
mass = density * volume
# Mass second moment of inertia for disk cross-section
mass_second_moment_of_inertia = np.zeros((3, 3), np.float64)
np.fill_diagonal(mass_second_moment_of_inertia, 2.0 / 5.0 * mass * base_radius ** 2)
# Inverse mass second of inertia
inv_mass_second_moment_of_inertia = np.linalg.inv(mass_second_moment_of_inertia)
test_sphere = Sphere(start, base_radius, density)
# checking origin and length of rod
assert_allclose(
test_sphere.position_collection[..., -1],
start,
atol=Tolerance.atol(),
)
# element lengths are equal for all rod.
# checking velocities, omegas and rest strains
# density and mass
assert_allclose(
test_sphere.velocity_collection, np.zeros((3, 1)), atol=Tolerance.atol()
)
correct_director_collection = np.zeros((3, 3, 1))
correct_director_collection[0] = normal
correct_director_collection[1] = binormal
correct_director_collection[2] = direction
assert_allclose(
test_sphere.director_collection,
correct_director_collection,
atol=Tolerance.atol(),
)
assert_allclose(
test_sphere.omega_collection, np.zeros((3, 1)), atol=Tolerance.atol()
)
assert_allclose(test_sphere.density, density, atol=Tolerance.atol())
# Check mass at each node. Note that, node masses is
# half of element mass at the first and last node.
assert_allclose(test_sphere.mass, mass, atol=Tolerance.atol())
# checking directors, rest length
# and shear, bend matrices and moment of inertia
assert_allclose(
test_sphere.inv_mass_second_moment_of_inertia[..., -1],
inv_mass_second_moment_of_inertia,
atol=Tolerance.atol(),
)