def init_mesh(self, n=0, meshtype='tri'):
""" generate the initial mesh
"""
node = np.array([(0, 0), (1, 0), (1, 1), (0, 1)], dtype=np.float)
cell = np.array([(1, 2, 0), (3, 0, 2)], dtype=np.int)
mesh = TriangleMesh(node, cell)
mesh.uniform_refine(2)
NN = mesh.number_of_nodes()
node = np.zeros((NN + 3, 2), dtype=np.float64)
node[:NN] = mesh.entity('node')
node[NN:] = node[[5], :]
cell = mesh.entity('cell')
cell[13][cell[13] == 5] = NN
cell[18][cell[18] == 5] = NN
cell[19][cell[19] == 5] = NN + 1
cell[12][cell[12] == 5] = NN + 1
cell[6][cell[6] == 5] = NN + 2
mesh = TriangleMesh(node, cell)
mesh.uniform_refine(n)
return mesh
def init_mesh(self, n=2):
from ..mesh import TriangleMesh
node = np.array([(0, 0), (1, 0), (1, 1), (0, 1)], dtype=np.float)
cell = np.array([(1, 2, 0), (3, 0, 2)], dtype=np.int)
mesh = TriangleMesh(node, cell)
mesh.uniform_refine(n)
NN = mesh.number_of_nodes()
node = np.zeros((NN + 3, 2), dtype=np.float64)
node[:NN] = mesh.entity('node')
node[NN:] = node[[5], :]
cell = mesh.entity('cell')
cell[13][cell[13] == 5] = NN
cell[18][cell[18] == 5] = NN
cell[19][cell[19] == 5] = NN + 1
cell[12][cell[12] == 5] = NN + 1
cell[6][cell[6] == 5] = NN + 2
return TriangleMesh(node, cell)
def refine_triangle_rbTest(self, l, plot=True, rb=True):
cell = np.array([[0, 1, 2], [0, 2, 3], [1, 4, 5], [2, 1, 5]],
dtype=np.int)
node = np.array([[0, 0], [1, 0], [1, 1], [0, 1], [2, 0], [2, 1]],
dtype=np.float)
mesh = TriangleMesh(node, cell)
#mesh.uniform_refine()
mesh = HalfEdgeMesh.from_mesh(mesh)
mesh.ds.cell2hedge = np.array([0, 3, 2, 11, 10])
c = np.array([0.2, 0.2])
r = 1.2
h = 1e-2
k = 0
NB = 0
start = time.time()
while k < l:
halfedge = mesh.ds.halfedge
halfedge1 = halfedge[:, 3]
node = mesh.node
flag = node - c
flag = flag[:, 0]**2 + flag[:, 1]**2
flag = flag <= r**2
flag1 = flag[halfedge[:, 0]].astype(int)
flag2 = flag[halfedge[halfedge1, 0]].astype(int)
markedge = flag1 + flag2 == 1
markedcell = halfedge[markedge, 1]
markedcell = np.unique(markedcell)
cell = np.unique(halfedge[:, 1])
nc = cell.shape[0]
markedcell1 = np.zeros(nc)
markedcell1[markedcell] = 1
if rb:
mesh.refine_triangle_rb(markedcell1)
else:
mesh.refine_triangle_rbg(markedcell1)
k += 1
print('循环', k, '次***************************')
#print('node', node)
#print('cell',cell)
end = time.time()
print(end - start)
if plot:
fig = plt.figure()
axes = fig.gca()
nindex = mesh.nodedata['level']
mesh.add_plot(axes)
#mesh.add_halfedge_plot(axes, showindex=True)
#mesh.find_node(axes, showindex=True, multiindex=nindex)
plt.show()
if 0:
fig = plt.figure()
axes = fig.gca()
mesh.add_plot(axes)
mesh.find_node(axes, showindex=True)
mesh.find_cell(axes, showindex=True)
cindex = np.arange(mesh.number_of_cells() - 1) + 1
fig = plt.figure()
axes = fig.gca()
mesh.add_plot(axes)
mesh.find_node(axes, showindex=True)
mesh.find_cell(axes, showindex=True, multiindex=cindex)
NN = mesh.number_of_nodes()
nindex = np.zeros(NN, dtype=np.int)
halfedge = mesh.ds.halfedge
nindex = mesh.nodedata['level']
cindex = mesh.get_data('cell', 'level')
fig = plt.figure()
axes = fig.gca()
mesh.add_plot(axes)
mesh.find_node(axes, showindex=True, multiindex=nindex)
mesh.find_cell(axes, showindex=True, multiindex=cindex)
plt.show()
from fealpy.mesh import TriangleMesh
domain = MeshInfo()
domain.set_points([(0,0),(1,0),(1,1),(0,1)])
domain.set_facets([(0,1),(1,2),(2,3),(3,0)], facet_markers=[1, 2, 3, 4])
mesh = build(domain, max_volume = 0.1**2, attributes=True)
node = np.array(mesh.points, dtype = np.float)
cell = np.array(mesh.elements, dtype = np.int)
tmesh = TriangleMesh(node, cell)
fig = plt.figure()
axes = fig.gca()
tmesh.add_plot(axes)
cell = tmesh.entity('cell')
node = tmesh.entity('node')
NN = tmesh.number_of_nodes()
isBdNode = tmesh.ds.boundary_node_flag()
newNode = np.zeros((NN, 2), dtype=np.float)
degree = np.zeros(NN, dtype=np.int)
np.add.at(degree, cell, 1)
for i in range(10):
#bc = tmesh.entity_barycenter('cell')
bc, R = tmesh.circumcenter()
np.add.at(newNode, (cell, np.s_[:]), bc[:, np.newaxis, :])
newNode /= degree[:, np.newaxis]
node[~isBdNode] = newNode[~isBdNode]
newNode[:] = 0
fig = plt.figure()
axes = fig.gca()
