def general_root(sigma):
""" The general case of the root of a grade 0,4 multivector """
output = general_root_val(sigma.value)
return [
cf.MultiVector(layout, output[0, :].copy()),
cf.MultiVector(layout, output[1, :].copy())
]
def ga_exp(B):
"""
Fast implementation of the translation and rotation specific exp function
"""
if np.sum(np.abs(B.value)) < np.finfo(float).eps:
return cf.MultiVector(layout, unit_scalar_mv.value)
return cf.MultiVector(layout, val_exp(B.value))
def test_rotor_between_objects(self):
# Make a big array of data
n_mvs = 1000
generator_list = [random_point_pair, random_line, random_circle, \
random_sphere, random_plane]
for generator in generator_list:
mv_a_array = np.array([generator() for i in range(n_mvs)], dtype=np.double)
mv_b_array = np.array([generator() for i in range(n_mvs)], dtype=np.double)
mv_c_array = np.zeros(mv_b_array.shape, dtype=np.double)
mv_d_array = np.zeros(mv_b_array.shape, dtype=np.double)
print('Starting kernel')
t = time.time()
blockdim = 64
griddim = int(math.ceil(n_mvs / blockdim))
rotor_between_objects_kernel[griddim, blockdim](mv_a_array, mv_b_array, mv_c_array)
end_time = time.time() - t
print('Kernel finished')
print(end_time)
# Now do the non cuda kernel
t = time.time()
for i in range(mv_a_array.shape[0]):
mv_a = cf.MultiVector(self.layout, mv_a_array[i, :])
mv_b = cf.MultiVector(self.layout, mv_b_array[i, :])
mv_d_array[i, :] = rotor_between_objects(mv_a, mv_b).value
print(time.time() - t)
np.testing.assert_almost_equal(mv_c_array, mv_d_array)
def neg_twiddle_root(C):
"""
Square Root and Logarithm of Rotors
in 3D Conformal Geometric Algebra
Using Polar Decomposition
Leo Dorst and Robert Valkenburg
"""
output = neg_twiddle_root_val(C.value)
return [
cf.MultiVector(layout, output[0, :]),
cf.MultiVector(layout, output[1, :])
]
def val_object_cost_function(obj_a_val, obj_b_val):
"""
Evaluates the rotor cost function between two objects
"""
grade_a = grade_obj_func(obj_a_val, gradeList, 0.0000001)
grade_b = grade_obj_func(obj_b_val, gradeList, 0.0000001)
if grade_a != grade_b:
return np.finfo(float).max
else:
R = rotor_between_objects(cf.MultiVector(layout, obj_a_val),
cf.MultiVector(layout, obj_b_val))
return np.abs(val_rotor_cost_sparse(R.value))
def rotor_between_objects(C1, C2):
"""
Hadfield and Lasenby AGACSE2018
For any two conformal objects C1 and C2 this returns a rotor that takes C1 to C2
Return a valid object from the addition result 1 + C2C1
"""
if float(gmt_func(C1.value, C1.value)[0]) > 0:
C = 1 + cf.MultiVector(layout, gmt_func(C2.value, C1.value))
R = pos_twiddle_root(C)[0]
return R
else:
return (1 -
cf.MultiVector(layout, gmt_func(C2.value, C1.value))).normal()
def test_normalise_mvs_kernel(self):
n_mvs = 500
mv_a_array = np.pi * np.array(
[random_line().value for i in range(n_mvs)])
mv_d_array = np.zeros(mv_a_array.shape)
mv_b_array = mv_a_array.copy()
print('Starting kernel')
t = time.time()
blockdim = 64
griddim = int(math.ceil(n_mvs / blockdim))
normalise_mvs_kernel[griddim, blockdim](mv_a_array)
end_time = time.time() - t
print('Kernel finished')
print(end_time)
# Now do the non cuda kernel
t = time.time()
for i in range(mv_a_array.shape[0]):
mv_a = cf.MultiVector(self.layout, mv_b_array[i, :])
mv_d_array[i, :] = mv_a.normal().value
print(time.time() - t)
np.testing.assert_almost_equal(mv_a_array, mv_d_array)
def MultiVector(self, *args, **kw):
'''
create a multivector in this layout
convenience func to Multivector(layout)
'''
return cf.MultiVector(layout=self, *args, **kw)
def parse_multivector(self, mv_string: str) -> 'cf.MultiVector':
""" Parses a multivector string into a MultiVector object """
# Get the names of the canonical blades
blade_name_index_map = {name: index for index, name in enumerate(self.names)}
# Clean up the input string a bit
cleaned_string = re.sub('[()]', '', mv_string)
# Create a multivector
mv_out = cf.MultiVector(self)
# Apply the regex
for m in _blade_pattern.finditer(cleaned_string):
# Clean up the search result
cleaned_match = m.group(0)
# Split on the '^'
stuff = cleaned_match.split('^')
if len(stuff) == 2:
# Extract the value of the blade and the index of the blade
blade_val = float("".join(stuff[0].split()))
blade_index = blade_name_index_map[stuff[1].strip()]
mv_out[blade_index] = blade_val
elif len(stuff) == 1:
# Extract the value of the scalar
blade_val = float("".join(stuff[0].split()))
blade_index = 0
mv_out[blade_index] = blade_val
return mv_out
def rotor_vector_to_vector(v1, v2):
""" Creates a rotor that takes one vector into another """
if np.sum(np.abs(v1.value - v2.value)) > 0.000001:
theta = angle_between_vectors(v1, v2)
return generate_rotation_rotor(theta, v1, v2)
else:
mv = cf.MultiVector(layout)
mv.value[0] = 1.0
return mv
def generate_dilation_rotor(scale):
"""
Generates a rotor that performs dilation about the origin
"""
if abs(scale - 1.0) < 0.00001:
u = np.zeros(32)
u[0] = 1.0
return cf.MultiVector(layout, u)
gamma = math.log(scale)
return math.cosh(gamma / 2) + math.sinh(gamma / 2) * (ninf ^ no)
def rotor_between_objects(X1, X2):
"""
Lasenby and Hadfield AGACSE2018
For any two conformal objects X1 and X2 this returns a rotor that takes X1 to X2
Return a valid object from the addition result 1 + gamma*X2X1
"""
return cf.MultiVector(
layout,
val_rotor_between_objects_root(val_normalised(X1.value),
val_normalised(X2.value)))
def val_convert_2D_polar_line_to_conformal_line(rho, theta):
""" Converts a 2D polar line to a conformal line """
a = np.cos(theta)
b = np.sin(theta)
x0 = a * rho
y0 = b * rho
x1 = int(x0 + 10000 * (-b))
y1 = int(y0 + 10000 * (a))
x2 = int(x0 - 10000 * (-b))
y2 = int(y0 - 10000 * (a))
p1_val = val_convert_2D_point_to_conformal(x1, y1)
p2_val = val_convert_2D_point_to_conformal(x2, y2)
line_val = omt_func(omt_func(p1_val, p2_val), ninf_val)
line_val = line_val / abs(cf.MultiVector(layout, line_val))
return line_val
def add(a, b):
return cf.MultiVector(a.layout, a.value + b.value)
def negate(a):
return cf.MultiVector(a.layout, -a.value)
def negative_root(sigma):
""" Square Root of Rotors - Evaluates the negative root """
res_val = negative_root_val(sigma.value)
return cf.MultiVector(layout, res_val)
def rotorconversion(x):
"""
Converts between the parameters of a TR bivector and the rotor that it is generating
"""
return cf.MultiVector(layout, val_rotorconversion(x))
def annhilate_k(K, C):
""" Removes K from C = KX via (K[0] - K[4])*C """
return cf.MultiVector(layout, val_annhilate_k(K.value, C.value))
def fast_dual(a):
"""
Fast dual
"""
return cf.MultiVector(layout, dual_func(a.value))
def rotor_between_planes(P1, P2):
""" return the rotor between two planes """
return cf.MultiVector(layout,
val_rotor_rotor_between_planes(P1.value, P2.value))
def val_distance_point_to_line(point, line):
"""
Returns the euclidean distance between a point and a line
"""
return float(abs(cf.MultiVector(layout, omt_func(point, line))))
def fast_down(mv):
""" A fast version of down() """
return cf.MultiVector(layout, val_down(mv.value))
def fast_up(mv):
""" Fast up mapping """
return cf.MultiVector(layout, val_up(mv.value))
def convert_2D_polar_line_to_conformal_line(rho, theta):
""" Converts a 2D polar line to a conformal line """
line_val = val_convert_2D_polar_line_to_conformal_line(rho, theta)
return cf.MultiVector(layout, line_val)
def normalised(mv):
""" fast version of the normal() function """
return cf.MultiVector(layout, val_normalised(mv.value))
def apply_rotor(mv_in, rotor):
""" Applies rotor to multivector in a fast way """
return cf.MultiVector(layout, val_apply_rotor(mv_in.value, rotor.value))
def add_e1(a):
return cf.MultiVector(a.layout, a.value + e1.value)
def convert_2D_point_to_conformal(x, y):
""" Convert a 2D point to conformal """
return cf.MultiVector(layout, val_convert_2D_point_to_conformal(x, y))
def apply_rotor_inv(mv_in, rotor, rotor_inv):
""" Applies rotor to multivector in a fast way takes pre computed adjoint"""
return cf.MultiVector(
layout, val_apply_rotor_inv(mv_in.value, rotor.value, rotor_inv.value))
def rotor_between_lines(L1, L2):
""" return the rotor between two lines """
return cf.MultiVector(layout, val_rotor_between_lines(L1.value, L2.value))
