pymor.discretizers package

Submodules

cg module

pymor.discretizers.cg.discretize_instationary_cg(analytical_problem, diameter=None, domain_discretizer=None, grid_type=None, grid=None, boundary_info=None, num_values=None, time_stepper=None, nt=None, preassemble=True)[source]

Discretizes an InstationaryProblem with a StationaryProblem as stationary part using finite elements.

Parameters

analytical_problem

The InstationaryProblem to discretize.

diameter

If not None, diameter is passed as an argument to the domain_discretizer.

domain_discretizer

Discretizer to be used for discretizing the analytical domain. This has to be a function domain_discretizer(domain_description, diameter, ...). If None, discretize_domain_default is used.

grid_type

If not None, this parameter is forwarded to domain_discretizer to specify the type of the generated Grid.

grid

Instead of using a domain discretizer, the Grid can also be passed directly using this parameter.

boundary_info

A BoundaryInfo specifying the boundary types of the grid boundary entities. Must be provided if grid is specified.

num_values

The number of returned vectors of the solution trajectory. If None, each intermediate vector that is calculated is returned.

time_stepper

The time-stepper to be used by solve.

nt

If time_stepper is not specified, the number of time steps for implicit Euler time stepping.

preassemble

If True, preassemble all operators in the resulting Model.

Returns

m

The Model that has been generated.

data

Dictionary with the following entries:

grid

The generated Grid.

boundary_info

The generated BoundaryInfo.

unassembled_m

In case preassemble is True, the generated Model before preassembling operators.

pymor.discretizers.cg.discretize_stationary_cg(analytical_problem, diameter=None, domain_discretizer=None, grid_type=None, grid=None, boundary_info=None, preassemble=True)[source]

Discretizes a StationaryProblem using finite elements.

Parameters

analytical_problem

The StationaryProblem to discretize.

diameter

If not None, diameter is passed as an argument to the domain_discretizer.

domain_discretizer

Discretizer to be used for discretizing the analytical domain. This has to be a function domain_discretizer(domain_description, diameter, ...). If None, discretize_domain_default is used.

grid_type

If not None, this parameter is forwarded to domain_discretizer to specify the type of the generated Grid.

grid

Instead of using a domain discretizer, the Grid can also be passed directly using this parameter.

boundary_info

A BoundaryInfo specifying the boundary types of the grid boundary entities. Must be provided if grid is specified.

preassemble

If True, preassemble all operators in the resulting Model.

Returns

m

The Model that has been generated.

data

Dictionary with the following entries:

grid

The generated Grid.

boundary_info

The generated BoundaryInfo.

unassembled_m

In case preassemble is True, the generated Model before preassembling operators.

disk module

pymor.discretizers.disk.discretize_instationary_from_disk(parameter_file, T=None, steps=None, u0=None, time_stepper=None)[source]

Load a linear affinely decomposed InstationaryModel from file.

Similarly to discretize_stationary_from_disk, the model is specified via an ini.-file of the following form

[system-matrices]
L_1.mat: l_1(μ_1,...,μ_n)
L_2.mat: l_2(μ_1,...,μ_n)
...

[rhs-vectors]
F_1.mat: f_1(μ_1,...,μ_n)
F_2.mat: f_2(μ_1,...,μ_n)
...

[mass-matrix]
D.mat

[initial-solution]
u0: u0.mat

[parameter]
μ_1: a_1,b_1
...
μ_n: a_n,b_n

[products]
Prod1: P_1.mat
Prod2: P_2.mat
...

[time]
T: final time
steps: number of time steps

Parameters

parameter_file

Path to the ‘.ini’ parameter file.

T

End-time of desired solution. If None, the value specified in the parameter file is used.

steps

Number of time steps to. If None, the value specified in the parameter file is used.

u0

Initial solution. If None the initial solution is obtained from parameter file.

time_stepper

The desired time stepper to use. If None, implicit Euler time stepping is used.

Returns

m

The InstationaryModel that has been generated.

pymor.discretizers.disk.discretize_stationary_from_disk(parameter_file)[source]

Load a linear affinely decomposed StationaryModel from file.

The model is defined via an .ini-style file as follows

[system-matrices]
L_1.mat: l_1(μ_1,...,μ_n)
L_2.mat: l_2(μ_1,...,μ_n)
...

[rhs-vectors]
F_1.mat: f_1(μ_1,...,μ_n)
F_2.mat: f_2(μ_1,...,μ_n)
...

[parameter]
μ_1: a_1,b_1
...
μ_n: a_n,b_n

[products]
Prod1: P_1.mat
Prod2: P_2.mat
...

Here, L_1.mat, L_2.mat, …, F_1.mat, F_2.mat, … are files containing matrices L_1, L_2, … and vectors F_1.mat, F_2.mat, … which correspond to the affine components of the operator and right-hand side. The respective coefficient functionals, are given via the string expressions l_1(...), l_2(...), …, f_1(...) in the (scalar-valued) Parameter components w_1, …, w_n. The allowed lower and upper bounds a_i, b_i for the component μ_i are specified in the [parameters] section. The resulting operator and right-hand side are then of the form

L(μ) = l_1(μ)*L_1 + l_2(μ)*L_2+ ...
F(μ) = f_1(μ)*F_1 + f_2(μ)*L_2+ ...

In the [products] section, an optional list of inner products Prod1, Prod2, .. with corresponding matrices P_1.mat, P_2.mat can be specified.

Example:

[system-matrices]
matrix1.mat: 1.
matrix2.mat: 1. - theta**2

[rhs-vectors]
rhs.mat: 1.

[parameter]
theta: 0, 0.5

[products]
h1: h1.mat
l2: mass.mat

Parameters

parameter_file

Path to the parameter file.

Returns

m

The StationaryModel that has been generated.

fv module

pymor.discretizers.fv.discretize_instationary_fv(analytical_problem, diameter=None, domain_discretizer=None, grid_type=None, num_flux='lax_friedrichs', lxf_lambda=1.0, eo_gausspoints=5, eo_intervals=1, grid=None, boundary_info=None, num_values=None, time_stepper=None, nt=None, preassemble=True)[source]

Discretizes an InstationaryProblem with a StationaryProblem as stationary part using the finite volume method.

Parameters

analytical_problem

The InstationaryProblem to discretize.

diameter

If not None, diameter is passed to the domain_discretizer.

domain_discretizer

Discretizer to be used for discretizing the analytical domain. This has to be a function domain_discretizer(domain_description, diameter, ...). If further arguments should be passed to the discretizer, use functools.partial. If None, discretize_domain_default is used.

grid_type

If not None, this parameter is forwarded to domain_discretizer to specify the type of the generated Grid.

num_flux

The numerical flux to use in the finite volume formulation. Allowed values are 'lax_friedrichs', 'engquist_osher', 'simplified_engquist_osher' (see pymor.operators.fv).

lxf_lambda

The stabilization parameter for the Lax-Friedrichs numerical flux (ignored, if different flux is chosen).

eo_gausspoints

Number of Gauss points for the Engquist-Osher numerical flux (ignored, if different flux is chosen).

eo_intervals

Number of sub-intervals to use for integration when using Engquist-Osher numerical flux (ignored, if different flux is chosen).

grid

Instead of using a domain discretizer, the Grid can also be passed directly using this parameter.

boundary_info

A BoundaryInfo specifying the boundary types of the grid boundary entities. Must be provided if grid is specified.

num_values

The number of returned vectors of the solution trajectory. If None, each intermediate vector that is calculated is returned.

time_stepper

The time-stepper to be used by solve.

nt

If time_stepper is not specified, the number of time steps for implicit Euler time stepping.

preassemble

If True, preassemble all operators in the resulting Model.

Returns

m

The Model that has been generated.

data

Dictionary with the following entries:

grid

The generated Grid.

boundary_info

The generated BoundaryInfo.

unassembled_m

In case preassemble is True, the generated Model before preassembling operators.

pymor.discretizers.fv.discretize_stationary_fv(analytical_problem, diameter=None, domain_discretizer=None, grid_type=None, num_flux='lax_friedrichs', lxf_lambda=1.0, eo_gausspoints=5, eo_intervals=1, grid=None, boundary_info=None, preassemble=True)[source]

Discretizes a StationaryProblem using the finite volume method.

Parameters

analytical_problem

The StationaryProblem to discretize.

diameter

If not None, diameter is passed as an argument to the domain_discretizer.

domain_discretizer

Discretizer to be used for discretizing the analytical domain. This has to be a function domain_discretizer(domain_description, diameter, ...). If None, discretize_domain_default is used.

grid_type

If not None, this parameter is forwarded to domain_discretizer to specify the type of the generated Grid.

num_flux

The numerical flux to use in the finite volume formulation. Allowed values are 'lax_friedrichs', 'engquist_osher', 'simplified_engquist_osher' (see pymor.operators.fv).

lxf_lambda

The stabilization parameter for the Lax-Friedrichs numerical flux (ignored, if different flux is chosen).

eo_gausspoints

Number of Gauss points for the Engquist-Osher numerical flux (ignored, if different flux is chosen).

eo_intervals

Number of sub-intervals to use for integration when using Engquist-Osher numerical flux (ignored, if different flux is chosen).

grid

Instead of using a domain discretizer, the Grid can also be passed directly using this parameter.

boundary_info

A BoundaryInfo specifying the boundary types of the grid boundary entities. Must be provided if grid is specified.

preassemble

If True, preassemble all operators in the resulting Model.

Returns

m

The Model that has been generated.

data

Dictionary with the following entries:

grid

The generated Grid.

boundary_info

The generated BoundaryInfo.

unassembled_m

In case preassemble is True, the generated Model before preassembling operators.