def orient(self):
"""
Orient this SimplicialMesh. If the manifold is of the same dimension as the
embedding (e.g. triangle mesh in 2D, tet mesh in 3D) then the resultant mesh
will be oriented so that the simplices have positive volume.
If the mesh is not orientable an Exception is raised.
"""
if self.manifold_dimension() == 0:
#0-dimensional manifold is alway oriented
return
if self.manifold_dimension() == self.embedding_dimension():
#orient w/ positive volumes
num_flips = 0
elements = self['elements']
vertices = self['vertices']
for row in elements:
pts = vertices[row]
if signed_volume(pts) < 0:
num_flips += 1
temp = row[0]
row[0] = row[1]
row[1] = temp
print("Flipped",num_flips,"simplices")
return
raise NotImplementedError
simplex_to_index = {}
for index,row in enumerate(self['elements']):
simplex_to_index[simplex(row)] = index
faces = self.skeleton(self.manifold_dimension() - 1)
face_to_simplex = dict.fromkeys(faces,set())
for simplex,index in simplex_to_index.keys():
for b in simplex.boundary():
face_to_simplex[b].add(index)
simplex_neigbors = [[]]*len(self['elements'])
for simplex,index in simplex_to_index.keys():
for b in simplex.boundary():
simplex_neigbors[index].append(face_to_simplex[b] - set([index]))
print(simplex_neighbors)
def orient(self):
"""
Orient this SimplicialMesh. If the manifold is of the same dimension as the
embedding (e.g. triangle mesh in 2D, tet mesh in 3D) then the resultant mesh
will be oriented so that the simplices have positive volume.
If the mesh is not orientable an Exception is raised.
"""
if self.manifold_dimension() == 0:
#0-dimensional manifold is alway oriented
return
if self.manifold_dimension() == self.embedding_dimension():
#orient w/ positive volumes
num_flips = 0
elements = self['elements']
vertices = self['vertices']
for row in elements:
pts = vertices[row]
if signed_volume(pts) < 0:
num_flips += 1
temp = row[0]
row[0] = row[1]
row[1] = temp
print "Flipped",num_flips,"simplices"
return
raise NotImplementedError
simplex_to_index = {}
for index,row in enumerate(self['elements']):
simplex_to_index[simplex(row)] = index
faces = self.skeleton(self.manifold_dimension() - 1)
face_to_simplex = dict.fromkeys(faces,set())
for simplex,index in simplex_to_index.iterkeys():
for b in simplex.boundary():
face_to_simplex[b].add(index)
simplex_neigbors = [[]]*len(self['elements'])
for simplex,index in simplex_to_index.iterkeys():
for b in simplex.boundary():
simplex_neigbors[index].append(face_to_simplex[b] - set([index]))
print simplex_neighbors
def compute_primal_volume(self,dim):
"""Compute the volume of all simplices for a given dimension
If the top simplex is of the same dimension as its embedding,
the signed volume is computed.
"""
data = self[dim]
data.primal_volume = zeros((data.num_simplices,))
if dim == self.embedding_dimension():
for i,s in enumerate(self.simplices):
pts = self.vertices[s,:]
data.primal_volume[i] = signed_volume(pts)
else:
for i,s in enumerate(data.simplices):
pts = self.vertices[s,:]
data.primal_volume[i] = unsigned_volume(pts)
