def test_eim_approximation_14(expression_type, basis_generation):
"""
The aim of this script is to test EIM/DEIM for nonlinear problems, extending test 13.
The difference with respect to test 13 is that a parametrized problem is defined but it is not
reduced any further. See the description of EIM and DEIM for test 13, taking care of the fact
that the high fidelity solution is used in place of the reduced order one.
"""
@StoreMapFromProblemNameToProblem
@StoreMapFromProblemToTrainingStatus
@StoreMapFromSolutionToProblem
class MockProblem(ParametrizedProblem):
def __init__(self, V, **kwargs):
# Call parent
ParametrizedProblem.__init__(
self,
os.path.join("test_eim_approximation_14_tempdir",
expression_type, basis_generation,
"mock_problem"))
# Minimal subset of a ParametrizedDifferentialProblem
self.V = V
self._solution = Function(V)
self.components = ["u", "s", "p"]
# Parametrized function to be interpolated
x = SpatialCoordinate(V.mesh())
mu = SymbolicParameters(self, V, (1., ))
self.f00 = (1 - x[0]) * cos(3 * pi * mu[0] *
(1 + x[0])) * exp(-mu[0] * (1 + x[0]))
self.f01 = (1 - x[0]) * sin(3 * pi * mu[0] *
(1 + x[0])) * exp(-mu[0] * (1 + x[0]))
# Inner product
f = TrialFunction(self.V)
g = TestFunction(self.V)
self.inner_product = assemble(inner(f, g) * dx)
# Collapsed vector and space
self.V0 = V.sub(0).collapse()
self.V00 = V.sub(0).sub(0).collapse()
self.V1 = V.sub(1).collapse()
def name(self):
return "MockProblem_14_" + expression_type + "_" + basis_generation
def init(self):
pass
def solve(self):
print("solving mock problem at mu =", self.mu)
assert not hasattr(self, "_is_solving")
self._is_solving = True
f00 = project(self.f00, self.V00)
f01 = project(self.f01, self.V00)
assign(self._solution.sub(0).sub(0), f00)
assign(self._solution.sub(0).sub(1), f01)
delattr(self, "_is_solving")
return self._solution
@StoreMapFromProblemToReductionMethod
class MockReductionMethod(ReductionMethod):
def __init__(self, truth_problem, **kwargs):
# Call parent
ReductionMethod.__init__(
self,
os.path.join("test_eim_approximation_14_tempdir",
expression_type, basis_generation,
"mock_problem"))
# Minimal subset of a DifferentialProblemReductionMethod
self.truth_problem = truth_problem
self.reduced_problem = None
def initialize_training_set(self,
ntrain,
enable_import=True,
sampling=None,
**kwargs):
return ReductionMethod.initialize_training_set(
self, self.truth_problem.mu_range, ntrain, enable_import,
sampling, **kwargs)
def initialize_testing_set(self,
ntest,
enable_import=False,
sampling=None,
**kwargs):
return ReductionMethod.initialize_testing_set(
self, self.truth_problem.mu_range, ntest, enable_import,
sampling, **kwargs)
def offline(self):
pass
def update_basis_matrix(self, snapshot):
pass
def error_analysis(self, N=None, **kwargs):
pass
def speedup_analysis(self, N=None, **kwargs):
pass
class ParametrizedFunctionApproximation(EIMApproximation):
def __init__(self, truth_problem, expression_type, basis_generation):
self.V = truth_problem.V1
(f0, _) = split(truth_problem._solution)
#
folder_prefix = os.path.join("test_eim_approximation_14_tempdir",
expression_type, basis_generation)
assert expression_type in ("Function", "Vector", "Matrix")
if expression_type == "Function":
# Call Parent constructor
EIMApproximation.__init__(self, truth_problem,
ParametrizedExpressionFactory(f0),
folder_prefix, basis_generation)
elif expression_type == "Vector":
v = TestFunction(self.V)
form = f0[0] * v * dx + f0[1] * v.dx(0) * dx
# Call Parent constructor
EIMApproximation.__init__(self, truth_problem,
ParametrizedTensorFactory(form),
folder_prefix, basis_generation)
elif expression_type == "Matrix":
u = TrialFunction(self.V)
v = TestFunction(self.V)
form = f0[0] * u * v * dx + f0[1] * u.dx(0) * v * dx
# Call Parent constructor
EIMApproximation.__init__(self, truth_problem,
ParametrizedTensorFactory(form),
folder_prefix, basis_generation)
else: # impossible to arrive here anyway thanks to the assert
raise AssertionError("Invalid expression_type")
# 1. Create the mesh for this test
mesh = IntervalMesh(100, -1., 1.)
# 2. Create Finite Element space (Lagrange P1)
element_0 = VectorElement("Lagrange", mesh.ufl_cell(), 2, dim=2)
element_1 = FiniteElement("Lagrange", mesh.ufl_cell(), 1)
element = MixedElement(element_0, element_1)
V = FunctionSpace(mesh, element, components=[["u", "s"], "p"])
# 3. Create a parametrized problem
problem = MockProblem(V)
mu_range = [
(1., pi),
]
problem.set_mu_range(mu_range)
# 4. Create a reduction method, but postpone generation of the reduced problem
MockReductionMethod(problem)
# 5. Allocate an object of the ParametrizedFunctionApproximation class
parametrized_function_approximation = ParametrizedFunctionApproximation(
problem, expression_type, basis_generation)
parametrized_function_approximation.set_mu_range(mu_range)
# 6. Prepare reduction with EIM
parametrized_function_reduction_method = EIMApproximationReductionMethod(
parametrized_function_approximation)
parametrized_function_reduction_method.set_Nmax(12)
parametrized_function_reduction_method.set_tolerance(0.)
# 7. Perform EIM offline phase
parametrized_function_reduction_method.initialize_training_set(
51, sampling=EquispacedDistribution())
reduced_parametrized_function_approximation = parametrized_function_reduction_method.offline(
)
# 8. Perform EIM online solve
online_mu = (1., )
reduced_parametrized_function_approximation.set_mu(online_mu)
reduced_parametrized_function_approximation.solve()
# 9. Perform EIM error analysis
parametrized_function_reduction_method.initialize_testing_set(100)
parametrized_function_reduction_method.error_analysis()
def test_eim_approximation_13(expression_type, basis_generation):
"""
The aim of this script is to test EIM/DEIM for nonlinear problems on mixed function spaces.
This test is an extension of test 11. The main difference with respect to test 11 is that a only a component
of the reduced order solution is required to define the parametrized expression/tensor.
* EIM: the expression to be interpolated is a component of the solution of the nonlinear reduced problem.
This results in a parametrized expression of type ListTensor.
* DEIM: the form to be interpolated contains a component of the solution of the nonlinear reduced problem,
split between x and y. This results in two coefficients in the integrand (denoted by f0[0] and f1[0] below)
which are of type Indexed.
"""
@StoreMapFromProblemNameToProblem
@StoreMapFromProblemToTrainingStatus
@StoreMapFromSolutionToProblem
class MockProblem(ParametrizedProblem):
def __init__(self, V, **kwargs):
# Call parent
ParametrizedProblem.__init__(
self,
os.path.join("test_eim_approximation_13_tempdir",
expression_type, basis_generation,
"mock_problem"))
# Minimal subset of a ParametrizedDifferentialProblem
self.V = V
self._solution = Function(V)
self.components = ["u", "s", "p"]
# Parametrized function to be interpolated
x = SpatialCoordinate(V.mesh())
mu = SymbolicParameters(self, V, (1., ))
self.f00 = (1 - x[0]) * cos(3 * pi * mu[0] *
(1 + x[0])) * exp(-mu[0] * (1 + x[0]))
self.f01 = (1 - x[0]) * sin(3 * pi * mu[0] *
(1 + x[0])) * exp(-mu[0] * (1 + x[0]))
# Inner product
f = TrialFunction(self.V)
g = TestFunction(self.V)
self.inner_product = assemble(inner(f, g) * dx)
# Collapsed vector and space
self.V0 = V.sub(0).collapse()
self.V00 = V.sub(0).sub(0).collapse()
self.V1 = V.sub(1).collapse()
def name(self):
return "MockProblem_13_" + expression_type + "_" + basis_generation
def init(self):
pass
def solve(self):
assert not hasattr(self, "_is_solving")
self._is_solving = True
f00 = project(self.f00, self.V00)
f01 = project(self.f01, self.V00)
assign(self._solution.sub(0).sub(0), f00)
assign(self._solution.sub(0).sub(1), f01)
delattr(self, "_is_solving")
return self._solution
@UpdateMapFromProblemToTrainingStatus
class MockReductionMethod(ReductionMethod):
def __init__(self, truth_problem, **kwargs):
# Call parent
ReductionMethod.__init__(
self,
os.path.join("test_eim_approximation_13_tempdir",
expression_type, basis_generation,
"mock_problem"))
# Minimal subset of a DifferentialProblemReductionMethod
self.truth_problem = truth_problem
self.reduced_problem = None
# I/O
self.folder["basis"] = os.path.join(
self.truth_problem.folder_prefix, "basis")
# Gram Schmidt
self.GS = GramSchmidt(self.truth_problem.inner_product)
def initialize_training_set(self,
ntrain,
enable_import=True,
sampling=None,
**kwargs):
return ReductionMethod.initialize_training_set(
self, self.truth_problem.mu_range, ntrain, enable_import,
sampling, **kwargs)
def initialize_testing_set(self,
ntest,
enable_import=False,
sampling=None,
**kwargs):
return ReductionMethod.initialize_testing_set(
self, self.truth_problem.mu_range, ntest, enable_import,
sampling, **kwargs)
def offline(self):
self.reduced_problem = MockReducedProblem(self.truth_problem)
if self.folder["basis"].create(
): # basis folder was not available yet
for (index, mu) in enumerate(self.training_set):
self.truth_problem.set_mu(mu)
print("solving mock problem at mu =",
self.truth_problem.mu)
f = self.truth_problem.solve()
component = "u" if index % 2 == 0 else "s"
self.reduced_problem.basis_functions.enrich(f, component)
self.GS.apply(
self.reduced_problem.basis_functions[component], 0)
self.reduced_problem.basis_functions.save(
self.folder["basis"], "basis")
else:
self.reduced_problem.basis_functions.load(
self.folder["basis"], "basis")
self._finalize_offline()
return self.reduced_problem
def error_analysis(self, N=None, **kwargs):
pass
def speedup_analysis(self, N=None, **kwargs):
pass
@StoreMapFromProblemToReducedProblem
class MockReducedProblem(ParametrizedProblem):
@sync_setters("truth_problem", "set_mu", "mu")
@sync_setters("truth_problem", "set_mu_range", "mu_range")
def __init__(self, truth_problem, **kwargs):
# Call parent
ParametrizedProblem.__init__(
self,
os.path.join("test_eim_approximation_13_tempdir",
expression_type, basis_generation,
"mock_problem"))
# Minimal subset of a ParametrizedReducedDifferentialProblem
self.truth_problem = truth_problem
self.basis_functions = BasisFunctionsMatrix(self.truth_problem.V)
self.basis_functions.init(self.truth_problem.components)
self._solution = None
def solve(self):
print("solving mock reduced problem at mu =", self.mu)
assert not hasattr(self, "_is_solving")
self._is_solving = True
f = self.truth_problem.solve()
f_N = transpose(
self.basis_functions) * self.truth_problem.inner_product * f
# Return the reduced solution
self._solution = OnlineFunction(f_N)
delattr(self, "_is_solving")
return self._solution
class ParametrizedFunctionApproximation(EIMApproximation):
def __init__(self, truth_problem, expression_type, basis_generation):
self.V = truth_problem.V1
(f0, _) = split(truth_problem._solution)
#
folder_prefix = os.path.join("test_eim_approximation_13_tempdir",
expression_type, basis_generation)
assert expression_type in ("Function", "Vector", "Matrix")
if expression_type == "Function":
# Call Parent constructor
EIMApproximation.__init__(self, truth_problem,
ParametrizedExpressionFactory(f0),
folder_prefix, basis_generation)
elif expression_type == "Vector":
v = TestFunction(self.V)
form = f0[0] * v * dx + f0[1] * v.dx(0) * dx
# Call Parent constructor
EIMApproximation.__init__(self, truth_problem,
ParametrizedTensorFactory(form),
folder_prefix, basis_generation)
elif expression_type == "Matrix":
u = TrialFunction(self.V)
v = TestFunction(self.V)
form = f0[0] * u * v * dx + f0[1] * u.dx(0) * v * dx
# Call Parent constructor
EIMApproximation.__init__(self, truth_problem,
ParametrizedTensorFactory(form),
folder_prefix, basis_generation)
else: # impossible to arrive here anyway thanks to the assert
raise AssertionError("Invalid expression_type")
# 1. Create the mesh for this test
mesh = IntervalMesh(100, -1., 1.)
# 2. Create Finite Element space (Lagrange P1)
element_0 = VectorElement("Lagrange", mesh.ufl_cell(), 2, dim=2)
element_1 = FiniteElement("Lagrange", mesh.ufl_cell(), 1)
element = MixedElement(element_0, element_1)
V = FunctionSpace(mesh, element, components=[["u", "s"], "p"])
# 3. Create a parametrized problem
problem = MockProblem(V)
mu_range = [
(1., pi),
]
problem.set_mu_range(mu_range)
# 4. Create a reduction method and run the offline phase to generate the corresponding
# reduced problem
reduction_method = MockReductionMethod(problem)
reduction_method.initialize_training_set(12,
sampling=EquispacedDistribution())
reduction_method.offline()
# 5. Allocate an object of the ParametrizedFunctionApproximation class
parametrized_function_approximation = ParametrizedFunctionApproximation(
problem, expression_type, basis_generation)
parametrized_function_approximation.set_mu_range(mu_range)
# 6. Prepare reduction with EIM
parametrized_function_reduction_method = EIMApproximationReductionMethod(
parametrized_function_approximation)
parametrized_function_reduction_method.set_Nmax(12)
parametrized_function_reduction_method.set_tolerance(0.)
# 7. Perform EIM offline phase
parametrized_function_reduction_method.initialize_training_set(
51, sampling=EquispacedDistribution())
reduced_parametrized_function_approximation = parametrized_function_reduction_method.offline(
)
# 8. Perform EIM online solve
online_mu = (1., )
reduced_parametrized_function_approximation.set_mu(online_mu)
reduced_parametrized_function_approximation.solve()
# 9. Perform EIM error analysis
parametrized_function_reduction_method.initialize_testing_set(100)
parametrized_function_reduction_method.error_analysis()