def refine_by_delaunay(self, triangles):
"""refines given elements by the delaunay refinement method"""
p = self.node_list
t = self.face_list
for tr in triangles:
pmid = (p[t[tr][0]] + p[t[tr][1]] + p[t[tr][2]]) / 3
p = np.append(p, [pmid], axis=0)
self.edge_length /= 2
dp = self.edge_length
for i in range(1, int(ceil(1 / dp))):
p = np.append(p, [[i * dp, 0]], axis=0)
for i in range(int(ceil(.5 / dp))):
p = np.append(p, [[1, i * dp]], axis=0)
for i in range(int(ceil(.5 / dp))):
p = np.append(p, [[1 - i * dp, .5]], axis=0)
for i in range(int(ceil(.5 / dp))):
p = np.append(p, [[.5, .5 + i * dp]], axis=0)
for i in range(int(ceil(.5 / dp))):
p = np.append(p, [[.5 - i * dp, 1]], axis=0)
for i in range(int(ceil(1 / dp))):
p = np.append(p, [[0, 1 - i * dp]], axis=0)
p = unique2d(p)
t = spspatial.Delaunay(p).vertices
# remove triangles where centroid outside boundary (good enough...)
pmid = p[t].sum(1) / 3
t = t[self.fd(pmid) < 1e-15]
t = [Face(t[i]) for i in range(len(t))]
self.node_list = p
self.face_list = t
def refine_by_delaunay(self, triangles):
"""refines given elements by the delaunay refinement method"""
p = self.node_list
t = self.face_list
for tr in triangles:
pmid = (p[t[tr][0]] + p[t[tr][1]] + p[t[tr][2]]) / 3
p = np.append(p, [pmid], axis=0)
self.edge_length /= 2
dp = self.edge_length
for i in range(1,int(ceil(1/dp))):
p = np.append(p, [[i*dp, 0]], axis=0)
for i in range(int(ceil(.5/dp))):
p = np.append(p, [[1, i*dp]], axis=0)
for i in range(int(ceil(.5/dp))):
p = np.append(p, [[1-i*dp, .5]], axis=0)
for i in range(int(ceil(.5/dp))):
p = np.append(p, [[.5, .5+i*dp]], axis=0)
for i in range(int(ceil(.5/dp))):
p = np.append(p, [[.5-i*dp, 1]], axis=0)
for i in range(int(ceil(1/dp))):
p = np.append(p, [[0, 1-i*dp]], axis=0)
p = unique2d(p)
t = spspatial.Delaunay(p).vertices
# remove triangles where centroid outside boundary (good enough...)
pmid = p[t].sum(1) / 3
t = t[self.fd(pmid) < 1e-15]
t = [Face(t[i]) for i in range(len(t))]
self.node_list = p
self.face_list = t
def create_equilateral_uniform_mesh(distance_function,
bounding_box,
edge_length,
fixed_points=None):
"""
distance_function > 0 outside, <0 inside, =0 boundary
bounding box = [xmin, xmax, ymin, ymax, ...]
edge_length = desired edge length of triangle
fixed points = clear
"""
geps = .001 * edge_length
xmin, xmax, ymin, ymax = bounding_box
mesh = TriangularMesh()
# make grid
x, y = np.mgrid[xmin:(xmax + edge_length):edge_length,
ymin:(ymax +
edge_length * np.sqrt(3) / 2):edge_length *
np.sqrt(3) / 2]
# shift even rows
#x[:, 1::2] += edge_length / 2
p = np.vstack((x.flat, y.flat)).T
for i in range(
int(ceil((ymax - ymin) / (edge_length * np.sqrt(3) / 2)))):
p = np.append(p, [[xmin, i * np.sqrt(3) / 2 * edge_length]],
axis=0)
p = np.append(p, [[xmax, i * np.sqrt(3) / 2 * edge_length]],
axis=0)
p = np.append(p, [[0.5, i * np.sqrt(3) / 2 * edge_length]], axis=0)
for i in range(int(ceil((xmax - xmin) / edge_length))):
p = np.append(p, [[xmin + 0.5 + i * edge_length, ymin + 0.5]],
axis=0)
# remove points outside boundary
p = p[distance_function(p) < -geps]
# add fixed points
if fixed_points is not None:
fixed_points = np.array(fixed_points, dtype='d')
p = np.vstack((fixed_points, p))
p = unique2d(p)
# triangulation
t = spspatial.Delaunay(p).vertices
# remove triangles where centroid outside boundary (good enough...)
pmid = p[t].sum(1) / 3
t = t[distance_function(pmid) < -1e-12]
# print distance_function(p[t].sum(1)/3)
mesh.set_mesh(p, t)
mesh.fd = distance_function
return mesh
def create_random_mesh(distance_function,
bounding_box,
number_of_points,
dist=0,
fixed_points=None):
"""
distance_function > 0 outside, <0 inside, =0 boundary
bounding box = [xmin, xmax, ymin, ymax, ...]
number of points = clear
dist = minimum distance for each new node to keep from all other points, default 0
fixed points = clear
if finding a new point fails more than 50 times, dist is set to dist=dist/sqrt(2)
"""
geps = 1e-10
n = number_of_points
xmin, xmax, ymin, ymax = bounding_box
mesh = TriangularMesh()
p = fixed_points
i = 0
failures = 0
while i < n:
pv = [np.random.uniform(xmin, xmax), np.random.uniform(ymin, ymax)]
if (dist == 0 or closest_node(pv, p) >= dist
) and distance_function([pv]) < -geps:
p = np.append(p, [pv], axis=0)
i += 1
else:
failures += 1
if failures > 50:
failures = 0
dist = dist / sqrt(2)
# remove duplicates
p = unique2d(p)
# triangulation
t = spspatial.Delaunay(p).vertices
# remove triangles where centroid outside boundary (good enough...)
pmid = p[t].sum(1) / 3
t = t[distance_function(pmid) < geps]
mesh.set_mesh(p, t)
mesh.fd = distance_function
return mesh
def create_equilateral_uniform_mesh(distance_function, bounding_box, edge_length, fixed_points=None):
"""
distance_function > 0 outside, <0 inside, =0 boundary
bounding box = [xmin, xmax, ymin, ymax, ...]
edge_length = desired edge length of triangle
fixed points = clear
"""
geps = .001 * edge_length
xmin, xmax, ymin, ymax = bounding_box
mesh = TriangularMesh()
# make grid
x, y = np.mgrid[xmin:(xmax + edge_length):edge_length,
ymin:(ymax + edge_length * np.sqrt(3) / 2):edge_length * np.sqrt(3) / 2]
# shift even rows
#x[:, 1::2] += edge_length / 2
p = np.vstack((x.flat, y.flat)).T
for i in range(int(ceil((ymax - ymin) / (edge_length * np.sqrt(3) / 2)))):
p = np.append(p, [[xmin, i * np.sqrt(3) / 2 * edge_length]], axis=0)
p = np.append(p, [[xmax, i * np.sqrt(3) / 2 * edge_length]], axis=0)
p = np.append(p, [[0.5, i * np.sqrt(3) / 2 * edge_length]], axis=0)
for i in range(int(ceil((xmax - xmin) / edge_length))):
p = np.append(p, [[xmin + 0.5 + i * edge_length, ymin + 0.5]], axis=0)
# remove points outside boundary
p = p[distance_function(p) < -geps]
# add fixed points
if fixed_points is not None:
fixed_points = np.array(fixed_points, dtype='d')
p = np.vstack((fixed_points, p))
p = unique2d(p)
# triangulation
t = spspatial.Delaunay(p).vertices
# remove triangles where centroid outside boundary (good enough...)
pmid = p[t].sum(1) / 3
t = t[distance_function(pmid) < -1e-12]
# print distance_function(p[t].sum(1)/3)
mesh.set_mesh(p, t)
mesh.fd = distance_function
return mesh
def create_bad_uniform_mesh(distance_function,
bounding_box,
edge_length,
fixed_points=None):
"""
distance_function > 0 outside, <0 inside, =0 boundary
bounding box = [xmin, xmax, ymin, ymax, ...]
edge_length = desired edge length of triangle
fixed points = clear
"""
geps = .001 * edge_length
xmin, xmax, ymin, ymax = bounding_box
mesh = TriangularMesh()
dx = edge_length / 5.
dy = edge_length * 5.
# make grid
x, y = np.mgrid[xmin:(xmax + dx):dx, ymin:ymax + dy:dy]
# shift even rows
#x[:, 0::2] += edge_length / 2
p = np.vstack((x.flat, y.flat)).T
# remove points outside boundary
p = p[distance_function(p) < geps]
# add fixed points
if fixed_points is not None:
fixed_points = np.array(fixed_points, dtype='d')
p = np.vstack((fixed_points, p))
p = unique2d(p)
t = spspatial.Delaunay(p).vertices
pmid = p[t].sum(1) / 3
t = t[distance_function(pmid) < geps]
# print distance_function(p[t].sum(1)/3)
mesh.set_mesh(p, t)
mesh.fd = distance_function
mesh.edge_length = edge_length
return mesh
def create_random_mesh(distance_function, bounding_box, number_of_points, dist=0, fixed_points=None):
"""
distance_function > 0 outside, <0 inside, =0 boundary
bounding box = [xmin, xmax, ymin, ymax, ...]
number of points = clear
dist = minimum distance for each new node to keep from all other points, default 0
fixed points = clear
if finding a new point fails more than 50 times, dist is set to dist=dist/sqrt(2)
"""
geps = 1e-10
n = number_of_points
xmin, xmax, ymin, ymax = bounding_box
mesh = TriangularMesh()
p = fixed_points
i = 0
failures = 0
while i < n:
pv = [np.random.uniform(xmin, xmax), np.random.uniform(ymin, ymax)]
if (dist == 0 or closest_node(pv, p) >= dist) and distance_function([pv]) < -geps:
p = np.append(p, [pv], axis=0)
i += 1
else:
failures += 1
if failures > 50:
failures = 0
dist = dist / sqrt(2)
# remove duplicates
p = unique2d(p)
# triangulation
t = spspatial.Delaunay(p).vertices
# remove triangles where centroid outside boundary (good enough...)
pmid = p[t].sum(1) / 3
t = t[distance_function(pmid) < geps]
mesh.set_mesh(p, t)
mesh.fd = distance_function
return mesh
def create_bad_uniform_mesh(distance_function, bounding_box, edge_length, fixed_points=None):
"""
distance_function > 0 outside, <0 inside, =0 boundary
bounding box = [xmin, xmax, ymin, ymax, ...]
edge_length = desired edge length of triangle
fixed points = clear
"""
geps = .001 * edge_length
xmin, xmax, ymin, ymax = bounding_box
mesh = TriangularMesh()
dx = edge_length/5.
dy = edge_length*5.
# make grid
x, y = np.mgrid[xmin:(xmax + dx):dx,
ymin:ymax + dy:dy]
# shift even rows
#x[:, 0::2] += edge_length / 2
p = np.vstack((x.flat, y.flat)).T
# remove points outside boundary
p = p[distance_function(p) < geps]
# add fixed points
if fixed_points is not None:
fixed_points = np.array(fixed_points, dtype='d')
p = np.vstack((fixed_points, p))
p = unique2d(p)
t = spspatial.Delaunay(p).vertices
pmid = p[t].sum(1) / 3
t = t[distance_function(pmid) < geps]
# print distance_function(p[t].sum(1)/3)
mesh.set_mesh(p, t)
mesh.fd = distance_function
mesh.edge_length = edge_length
return mesh
