def init_mesh(self, n=9, meshtype='tet'):
node = np.array([[-1, -1, -1], [1, -1, -1], [1, 1, -1], [-1, 1, -1],
[-1, -1, 1], [1, -1, 1], [1, 1, 1], [-1, 1, 1]],
dtype=np.float)
cell = np.array([[0, 1, 2, 6], [0, 5, 1, 6], [0, 4, 5, 6],
[0, 7, 4, 6], [0, 3, 7, 6], [0, 2, 3, 6]],
dtype=np.int)
mesh = TetrahedronMesh(node, cell)
for i in range(n):
mesh.bisect()
NN = mesh.number_of_nodes()
node = mesh.entity('node')
cell = mesh.entity('cell')
bc = mesh.entity_barycenter('cell')
isDelCell = ((bc[:, 0] > 0) & (bc[:, 1] < 0))
cell = cell[~isDelCell]
isValidNode = np.zeros(NN, dtype=np.bool)
isValidNode[cell] = True
node = node[isValidNode]
idxMap = np.zeros(NN, dtype=mesh.itype)
idxMap[isValidNode] = range(isValidNode.sum())
cell = idxMap[cell]
mesh = TetrahedronMesh(node, cell)
return mesh
def test_tetrahedron_mesh():
from fealpy.mesh import TetrahedronMesh
node = np.array(
[[0.0, 0.0, 0.0], [1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]],
dtype=np.float64)
cell = np.array([[0, 1, 2, 3]], dtype=np.int_)
mesh = TetrahedronMesh(node, cell)
# 获取测试
assert id(node) == id(mesh.entity('node'))
assert id(cell) == id(mesh.entity('cell'))
isBdNode = mesh.ds.boundary_node_flag()
assert np.all(isBdNode)
isBdEdge = mesh.ds.boundary_edge_flag()
assert np.all(isBdEdge)
isBdFace = mesh.ds.boundary_face_flag()
assert np.all(isBdFace)
cell2node = mesh.ds.cell_to_node()
cell2edge = mesh.ds.cell_to_edge()
cell2face = mesh.ds.cell_to_face()
cell2cell = mesh.ds.cell_to_cell()
edge2node = mesh.ds.edge_to_node()
edge2edge = mesh.ds.edge_to_edge()
edge2face = mesh.ds.edge_to_face()
edge2cell = mesh.ds.edge_to_cell()
face2node = mesh.ds.face_to_node()
face2edge = mesh.ds.face_to_edge()
face2face = mesh.ds.face_to_face()
face2cell = mesh.ds.face_to_cell()
node2node = mesh.ds.node_to_node()
node2edge = mesh.ds.node_to_edge()
node2face = mesh.ds.node_to_face()
node2cell = mesh.ds.node_to_cell()
mesh.uniform_refine()
from fealpy.mesh import TetrahedronMesh
from fealpy.mesh import TriangleMesh
point = np.array([[-1, -1, -1], [1, -1, -1], [1, 1, -1], [-1, 1, -1],
[-1, -1, 1], [1, -1, 1], [1, 1, 1], [-1, 1, 1]],
dtype=np.float)
cell = np.array([[0, 1, 2, 6], [0, 5, 1, 6], [0, 4, 5, 6], [0, 7, 4, 6],
[0, 3, 7, 6], [0, 2, 3, 6]],
dtype=np.int)
mesh = TetrahedronMesh(point, cell)
mesh.uniform_refine(3)
face = mesh.entity('face')
isBdFace = mesh.ds.boundary_face_flag()
cell = face[isBdFace]
node = mesh.entity('node')
NN = mesh.number_of_nodes()
isBDNode = mesh.ds.boundary_node_flag()
NB = np.sum(isBDNode)
idxmap = np.zeros(NN, dtype=np.int32)
idxmap[isBDNode] = range(NB)
cell = idxmap[cell]
node = node[isBDNode]
trimesh = TriangleMesh(node, cell)
data = {'node': trimesh.node, 'elem': trimesh.ds.cell + 1}