def test_matrix_operator_equivalency():
t = 0.0
for bc in [boundary.Periodic(), boundary.Extrapolation()]:
for nonlinear_hyper_diffusion in test_problems:
nonlinear_hyper_diffusion.initial_condition = x_functions.Sine(
offset=2.0)
for num_basis_cpts in range(1, 6):
for basis_class in basis.BASIS_LIST:
basis_ = basis_class(num_basis_cpts)
mesh_ = mesh.Mesh1DUniform(0.0, 1.0, 20)
dg_solution = basis_.project(
nonlinear_hyper_diffusion.initial_condition, mesh_)
L = nonlinear_hyper_diffusion.ldg_operator(
dg_solution, t, bc, bc, bc, bc)
dg_vector = dg_solution.to_vector()
tuple_ = nonlinear_hyper_diffusion.ldg_matrix(
dg_solution, t, bc, bc, bc, bc)
matrix = tuple_[0]
vector = tuple_[1]
dg_error_vector = (L.to_vector() -
np.matmul(matrix, dg_vector) - vector)
dg_error = solution.DGSolution(dg_error_vector, basis_,
mesh_)
error = dg_error.norm() / L.norm()
# plot.plot_dg_1d(dg_error)
assert error <= tolerance
def solve_function(d, e, t, rhs, q_old, t_old, delta_t, F, stages,
stage_num):
(matrix, vector) = matrix_function(t)
q_vector = np.linalg.solve(d * identity + e * matrix,
rhs.to_vector() - e * vector)
dg_solution = solution.DGSolution(q_vector, rhs.basis, rhs.mesh)
return dg_solution
def solve_function(d, e, t, rhs, q_old, t_old, delta_t, F, stages,
stage_num):
if vector is not None:
q_vector = np.linalg.solve(d * identity + e * matrix,
rhs.to_vector() - e * vector)
else:
q_vector = np.linalg.solve(d * identity + e * matrix,
rhs.to_vector())
return solution.DGSolution(q_vector, rhs.basis, rhs.mesh)
def test_compute_quadrature_matrix():
squared = flux_functions.Polynomial(degree=2)
cubed = flux_functions.Polynomial(degree=3)
initial_condition = functions.Sine()
t = 0.0
x_left = 0.0
x_right = 1.0
for f in [squared, cubed]:
for basis_class in basis.BASIS_LIST:
for num_basis_cpts in range(1, 6):
error_list = []
basis_ = basis_class(num_basis_cpts)
for num_elems in [10, 20]:
mesh_ = mesh.Mesh1DUniform(x_left, x_right, num_elems)
dg_solution = basis_.project(initial_condition, mesh_)
quadrature_matrix = ldg_utils.compute_quadrature_matrix(
dg_solution, t, f)
result = solution.DGSolution(None, basis_, mesh_)
direct_quadrature = solution.DGSolution(
None, basis_, mesh_)
for i in range(mesh_.num_elems):
# compute value as B_i Q_i
result[i] = np.matmul(quadrature_matrix[i],
dg_solution[i])
# also compute quadrature directly
for l in range(basis_.num_basis_cpts):
quadrature_function = (lambda xi: f(
initial_condition(
mesh_.transform_to_mesh(xi, i)),
xi,
) * initial_condition(
mesh_.transform_to_mesh(xi, i)) * basis_.
derivative(xi, l))
direct_quadrature[i, l] = math_utils.quadrature(
quadrature_function, -1.0, 1.0)
# need to multiply by mass inverse
direct_quadrature[i] = np.matmul(
basis_.mass_matrix_inverse, direct_quadrature[i])
error = (result - direct_quadrature).norm()
error_list.append(error)
if error_list[-1] != 0.0:
order = utils.convergence_order(error_list)
assert order >= (num_basis_cpts - 1)
def fd_to_dg(fd_solution, boundary_condition=None):
if boundary_condition is None:
boundary_condition = boundary.Extrapolation()
num_elems = fd_solution.mesh.num_elems
basis_class = type(fd_solution.basis)
basis_ = basis_class(2)
dg_solution = solution.DGSolution(None, basis_, fd_solution.mesh)
dg_solution[:, 0] = fd_solution.coeffs[:, 0]
for i in range(num_elems):
dg_solution[:, 1]
return dg_solution
def solve_function(d, e, t, rhs, q_old, t_old, delta_t, F, stages,
stage_num):
basis_ = q_old.basis_
mesh_ = q_old.mesh_
num_eqns = q_old.num_eqns
def func(coeffs):
q = solution.DGSolution(coeffs, basis_, mesh_, num_eqns)
result = d * q + e * F(t, q) - rhs
return result.coeffs
solution_coeffs = scipy.optimize.newton_krylov(func, rhs.coeffs)
return solution.DGSolution(solution_coeffs, basis_, mesh_, num_eqns)
def solve_function(d, e, t, rhs, q_old, t_old, delta_t, F, stages,
stage_num):
if stage_num > 0:
q = stages[stage_num - 1]
else:
q = q_old
for i in range(num_picard_iterations):
(matrix, vector) = matrix_function(t, q)
q_vector = np.linalg.solve(d * identity + e * matrix,
rhs.to_vector() - e * vector)
q = solution.DGSolution(q_vector, rhs.basis, rhs.mesh)
return q
def rhs_function(t, q, app_):
num_elems = q.mesh_.num_elems
delta_x = q.mesh_.delta_x
a = -1.0 / delta_x
F = solution.DGSolution(None, q.basis_, q.mesh_, q.num_eqns)
# assume periodic boundary conditions
f = fluctuations(q[num_elems - 1, :, :], q[0, :, :], app_)
F[num_elems - 1, :, :] += a * f[0]
F[0, :, :] += a * f[1]
for i in range(1, num_elems):
# f = (A^- \Delta Q_{i-1/2}, A^+ \Delta Q_{i-1/2})
f = fluctuations(q[i - 1, :, :], q[i, :, :], app_)
F[i - 1, :, :] += a * f[0]
F[i, :, :] += a * f[1]
return F
def wave_propagation_formulation(
dg_solution, t, app_, fluctuation_solver, boundary_condition,
):
# Wave Propagation Method
# Q^{n+1}_i = Q^n - delta_t/delta_x (A^+ \Delta Q_{i-1/2} + A^- \Delta Q_{i+1/2})
# Wave Propagation Operator
# F(t, q)_i = - 1/delta_x (A^+ \Delta Q_{i-1/2} + A^- \Delta Q_{i+1/2})
F = solution.DGSolution(
None, dg_solution.basis_, dg_solution.mesh_, dg_solution.num_eqns
)
# compute fluctuations and add to F
mesh_ = dg_solution.mesh_
for face_index in mesh_.boundary_faces:
left_elem_index = mesh_.faces_to_elems[face_index, 0]
right_elem_index = mesh_.faces_to_elems[face_index, 1]
fluctuations = boundary_condition.evaluate_boundary(
dg_solution, face_index, fluctuation_solver, t
)
if left_elem_index != -1:
F[left_elem_index, :, :] += (
-1.0 / mesh_.elem_volumes[left_elem_index] * fluctuations[0]
)
elif right_elem_index != -1:
F[right_elem_index, :, :] += (
-1.0 / mesh_.elem_volumes[right_elem_index] * fluctuations[1]
)
for face_index in mesh_.interior_faces:
left_elem_index = mesh_.faces_to_elems[face_index, 0]
right_elem_index = mesh_.faces_to_elems[face_index, 1]
fluctuations = fluctuation_solver.solve(dg_solution, face_index, t)
F[left_elem_index, :, :] += (
-1.0 / mesh_.elem_volumes[left_elem_index] * fluctuations[0]
)
F[right_elem_index, :, :] += (
-1.0 / mesh_.elem_volumes[right_elem_index] * fluctuations[1]
)
return F
def read_dogpack_dir(output_dir):
parameters_file = output_dir + "/parameters.ini"
params = parse_parameters.parse_ini_parameters(output_dir, parameters_file)
mesh_ = mesh.from_dogpack_params(params)
basis_ = basis_factory.from_dogpack_params(params)
num_frames = params["num_frames"]
space_order = basis_.space_order
num_basis_cpts = basis_.num_basis_cpts
num_elems = mesh_.num_elems
num_eqns = params["num_eqns"]
m_tmp = num_elems * num_eqns * num_basis_cpts
dg_solution_list = []
time_list = []
for i_frame in range(num_frames + 1):
q_filename = "q" + str(i_frame).zfill(4) + ".dat"
with open(output_dir + "/" + q_filename, "r") as q_file:
# get time
linestring = q_file.readline()
linelist = linestring.split()
time = np.float64(linelist[0])
time_list.append(time)
# store all Legendre coefficients in q_tmp
q_tmp = np.zeros(m_tmp, dtype=np.float64)
for k in range(0, m_tmp):
linestring = q_file.readline()
linelist = linestring.split()
q_tmp[k] = np.float64(linelist[0])
q_tmp = q_tmp.reshape((num_basis_cpts, num_eqns, num_elems))
# rearrange to match PyDogPack configuration
coeffs = np.einsum("ijk->kji", q_tmp)
dg_solution = solution.DGSolution(coeffs, basis_, mesh_, num_eqns)
dg_solution_list.append(dg_solution)
return dg_solution_list, time_list
def func(coeffs):
q = solution.DGSolution(coeffs, basis_, mesh_, num_eqns)
result = d * q + e * F(t, q) - rhs
return result.coeffs
def test_to_from_vector():
dg_solution_vector = dg_solution.to_vector()
assert len(dg_solution_vector.shape) == 1
new_solution = solution.DGSolution(None, basis_, mesh_)
new_solution.from_vector(dg_solution_vector)
assert new_solution == dg_solution
from pydogpack.solution import solution
from pydogpack.basis import basis
from pydogpack.mesh import mesh
from pydogpack.utils import functions
from pydogpack.utils import x_functions
import numpy as np
basis_ = basis.LegendreBasis1D(4)
mesh_ = mesh.Mesh1DUniform(0.0, 1.0, 40)
dg_solution = solution.DGSolution(None, basis_, mesh_)
tolerance = 1e-8
tolerance_2 = 0.1
def test_call():
assert dg_solution(0.0) == 0.0
def test_evaluate_canonical():
assert dg_solution.evaluate_canonical(1.0, 1) == 0.0
def test_evaluate_gradient():
assert dg_solution.evaluate_gradient(0.5) == 0.0
def test_evaluate_gradient_mesh():
assert dg_solution.evaluate_gradient_mesh(0.5) == 0.0
def evaluate_weak_form(
dg_solution,
t,
flux_function,
riemann_solver,
boundary_condition,
nonconservative_function=None,
regularization_path=None,
source_function=None,
):
# \v{q}_t + \div_x \M{f}(\v{q}, x, t) + g(\v{q}, x, t) \v{q}_x = \v{s}(\v{q}, x, t)
# See notes for derivation of dg formulation
# \M{Q}_{i,t} =
# \dintt{\mcK}{}{\M{f}\p{\M{Q}_i \v{\phi}(\v{\xi}), \v{b}_i(\v{\xi}), t}
# \p{\v{\phi}'(\v{\xi}) \v{c}_i'(\v{b}_i(\v{\xi}))}^T}{\v{\xi}} \M{M}^{-1}
# - 1/m_i \dintt{\partial K_i}{}{\M{f}^* \v{n} \v{\phi}_i^T(\v{x})}{s} \M{M}^{-1}
# + \dintt{\mcK}{}{\v{s}\p{\M{Q}_i \v{\phi}_i(\v{x}), \v{x}, t}
# \v{\phi}^T\p{\v{\xi}}}{\v{\xi}} \M{M}^{-1}
#
# - 1/m_i \dintt{-1}{1}{g(Q_i \v{\phi}) Q_i \v{\phi}_{\xi}(\xi)
# \v{\phi}^T(\xi)}{\xi} M^{-1}
# - 1/(2m_i)\dintt{0}{1}{g(\v{\psi}(s, Q_{i-1} \v{\phi}(1), Q_i \v{\phi}(-1)))
# \v{\psi}_s(s, Q_{i-1}\v{\phi}(1), Q_i \v{\phi}(-1))}{s}
# \v{\phi}^T(-1) M^{-1}
# - 1/(2m_i)\dintt{0}{1}{g(\v{\psi}(s, Q_i \v{\phi}(1), Q_{i+1}\v{\phi}(-1)))
# \v{\psi}_s(s, Q_i \v{\phi}(1), Q_{i+1} \v{\phi}(-1))}{s}
# \v{\phi}^T(1) M^{-1}
# dg_solution = Q, with mesh and basis
# numerical_fluxes = \M{f}^*
# source_function = \v{s}(\v{q}_h, x, t)
# if source_function is None assume zero source function
mesh_ = dg_solution.mesh_
basis_ = dg_solution.basis_
transformed_solution = solution.DGSolution(None, basis_, mesh_,
dg_solution.num_eqns)
# import ipdb; ipdb.set_trace()
if source_function is not None:
transformed_solution = evaluate_source_term(transformed_solution,
source_function,
dg_solution, t)
if basis_.num_basis_cpts > 1:
transformed_solution = project_flux_onto_gradient(
transformed_solution, dg_solution, flux_function, t)
# numerical_fluxes should be approximate riemann solutions at quadrature points
# on every face
numerical_fluxes = evaluate_fluxes(dg_solution, t, boundary_condition,
riemann_solver)
transformed_solution = evaluate_weak_flux(transformed_solution,
numerical_fluxes)
if nonconservative_function is not None:
transformed_solution = evaluate_nonconservative_term(
transformed_solution,
nonconservative_function,
regularization_path,
dg_solution,
t,
boundary_condition,
)
return transformed_solution
def dg_to_fd(dg_solution):
basis_class = type(dg_solution.basis)
basis_ = basis_class(1)
fd_solution = solution.DGSolution(dg_solution.coeffs[:, 0], basis_,
dg_solution.mesh)
return fd_solution
