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restructured mesh_rigid_body.py and test_mesh_rigid_body.py
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@Ali-7800
Ali-7800 committed Apr 24, 2024
1 parent 286c147 commit 665f55a
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Showing 2 changed files with 291 additions and 1,238 deletions.
87 changes: 47 additions & 40 deletions elastica/rigidbody/mesh_rigid_body.py
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Original file line number Diff line number Diff line change
Expand Up @@ -34,9 +34,17 @@ def __init__(
self.density = density
self.volume = volume
self.mass = np.array([self.volume * self.density])
self.mass_second_moment_of_inertia = mass_second_moment_of_inertia.reshape(
MaxDimension.value(), MaxDimension.value(), 1
)

self.inv_mass_second_moment_of_inertia = np.linalg.inv(
mass_second_moment_of_inertia
).reshape(MaxDimension.value(), MaxDimension.value(), 1)
normal = np.array([1.0, 0.0, 0.0]).reshape(3, 1)
tangents = np.array([0.0, 0.0, 1.0]).reshape(3, 1)
binormal = _batch_cross(tangents, normal)

# initialize material frame to be the same as lab frame
self.director_collection = np.zeros(
(MaxDimension.value(), MaxDimension.value(), 1)
Expand All @@ -48,51 +56,46 @@ def __init__(
self.n_faces = mesh.faces.shape[-1]
self.face_centers = np.array(mesh.face_centers.copy())
self.face_normals = np.array(mesh.face_normals.copy())
self.distance_to_face_centers = _batch_norm(

# since material frame is the same as lab frame initially, no need to convert this from lab to material
self.distance_to_face_centers_from_center_of_mass = _batch_norm(
self.face_centers - center_of_mass.reshape(3, 1)
)
self.direction_to_face_centers = (
self.direction_to_face_centers_from_center_of_mass_in_material_frame = (
self.face_centers - center_of_mass.reshape(3, 1)
) / self.distance_to_face_centers
self.distance_to_faces = np.zeros((MaxDimension.value(), self.n_faces))
self.direction_to_faces = np.zeros(
) / self.distance_to_face_centers_from_center_of_mass
self.distance_to_faces_from_center_of_mass = np.zeros(
(MaxDimension.value(), self.n_faces)
)
self.direction_to_faces_from_center_of_mass_in_material_frame = np.zeros(
(MaxDimension.value(), MaxDimension.value(), self.n_faces)
)
for i in range(MaxDimension.value()):
for k in range(self.n_faces):
self.distance_to_faces[i, k] = np.linalg.norm(
self.distance_to_faces_from_center_of_mass[i, k] = np.linalg.norm(
self.faces[:, i, k] - center_of_mass
)
self.direction_to_faces[:, i, k] = (
self.direction_to_faces_from_center_of_mass_in_material_frame[
:, i, k
] = (
self.faces[:, i, k] - center_of_mass
) / self.distance_to_faces[i, k]
) / self.distance_to_faces_from_center_of_mass[
i, k
]

self.mass_second_moment_of_inertia = mass_second_moment_of_inertia.reshape(
MaxDimension.value(), MaxDimension.value(), 1
self.face_normals_in_material_frame = np.zeros(
(MaxDimension.value(), self.n_faces)
)
self.face_normals_in_material_frame = self.face_normals.copy()

self.inv_mass_second_moment_of_inertia = np.linalg.inv(
mass_second_moment_of_inertia
).reshape(MaxDimension.value(), MaxDimension.value(), 1)

# position is at the center
# position is at the center of mass
self.position_collection = np.zeros((MaxDimension.value(), 1))
self.position_collection[:, 0] = center_of_mass

self.velocity_collection = np.zeros((MaxDimension.value(), 1))
self.omega_collection = np.zeros((MaxDimension.value(), 1))
self.acceleration_collection = np.zeros((MaxDimension.value(), 1))
self.alpha_collection = np.zeros((MaxDimension.value(), 1))
self.face_normals_lagrangian = np.zeros((MaxDimension.value(), self.n_faces))

# self.face_normals_lagrangian = self.director_collection[...,0][email protected]_normals
# for i in range(3):
# for j in range(3):
# for k in range(self.n_faces):
# self.face_normals_lagrangian[i, k] += (
# self.director_collection[j, i, 0] * self.face_normals[j, k]
# )
self.face_normals_lagrangian = self.face_normals.copy()

self.external_forces = np.zeros((MaxDimension.value())).reshape(
MaxDimension.value(), 1
Expand All @@ -106,22 +109,22 @@ def update_faces(self):
self.director_collection,
self.faces,
self.position_collection,
self.distance_to_faces,
self.direction_to_faces,
self.distance_to_faces_from_center_of_mass,
self.direction_to_faces_from_center_of_mass_in_material_frame,
self.n_faces,
)
_update_face_centers(
self.director_collection,
self.face_centers,
self.position_collection,
self.distance_to_face_centers,
self.direction_to_face_centers,
self.distance_to_face_centers_from_center_of_mass,
self.direction_to_face_centers_from_center_of_mass_in_material_frame,
self.n_faces,
)
_update_face_normals(
self.director_collection,
self.face_normals,
self.face_normals_lagrangian,
self.face_normals_in_material_frame,
self.n_faces,
)

Expand All @@ -131,8 +134,8 @@ def _update_face_centers(
director_collection,
face_centers,
center_of_mass,
distance_to_face_centers,
direction_to_face_centers,
distance_to_face_centers_from_center_of_mass,
direction_to_face_centers_from_center_of_mass_in_material_frame,
n_faces,
):
face_centers[:] = np.zeros((3, n_faces))
Expand All @@ -141,9 +144,11 @@ def _update_face_centers(
face_centers[i, k] += center_of_mass[i, 0]
for j in range(3):
face_centers[i, k] += (
distance_to_face_centers[i]
distance_to_face_centers_from_center_of_mass[i]
* director_collection[i, j, 0]
* direction_to_face_centers[j, k]
* direction_to_face_centers_from_center_of_mass_in_material_frame[
j, k
]
)


Expand All @@ -152,8 +157,8 @@ def _update_faces(
director_collection,
faces,
center_of_mass,
distance_to_faces,
direction_to_faces,
distance_to_faces_from_center_of_mass,
direction_to_faces_from_center_of_mass_in_material_frame,
n_faces,
):
faces[:] = np.zeros((3, 3, n_faces)) # dim,vertices,faces
Expand All @@ -163,17 +168,19 @@ def _update_faces(
faces[i, m, k] += center_of_mass[i, 0]
for j in range(3):
faces[i, m, k] += (
distance_to_faces[m, k]
distance_to_faces_from_center_of_mass[m, k]
* director_collection[i, j, 0]
* direction_to_faces[j, m, k]
* direction_to_faces_from_center_of_mass_in_material_frame[
j, m, k
]
)


@numba.njit(cache=True)
def _update_face_normals(
director_collection,
face_normals,
face_normals_lagrangian,
face_normals_in_material_frame,
n_faces,
):

Expand All @@ -182,5 +189,5 @@ def _update_face_normals(
for j in range(3):
for k in range(n_faces):
face_normals[i, k] += (
director_collection[i, j, 0] * face_normals_lagrangian[j, k]
director_collection[i, j, 0] * face_normals_in_material_frame[j, k]
)
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