gemseo / mda

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mda_chain module

An advanced MDA splitting algorithm based on graphs.

class gemseo.mda.mda_chain.MDAChain(disciplines, inner_mda_name='MDAJacobi', max_mda_iter=20, name='', n_processes=2, chain_linearize=False, tolerance=1e-06, linear_solver_tolerance=1e-12, use_lu_fact=False, grammar_type=GrammarType.JSON, coupling_structure=None, sub_coupling_structures=None, log_convergence=False, linear_solver='DEFAULT', linear_solver_options=None, mdachain_parallelize_tasks=False, mdachain_parallel_options=None, initialize_defaults=False, **inner_mda_options)[source]

Bases: BaseMDA

A chain of MDAs.

The execution sequence is provided by the DependencyGraph.

Initialize self. See help(type(self)) for accurate signature.

Parameters:
  • disciplines (Sequence[MDODiscipline]) – The disciplines from which to compute the MDA.

  • inner_mda_name (str) –

    The class name of the inner-MDA.

    By default it is set to “MDAJacobi”.

  • max_mda_iter (int) –

    The maximum iterations number for the MDA algorithm.

    By default it is set to 20.

  • name (str) –

    The name to be given to the MDA. If None, use the name of the class.

    By default it is set to “”.

  • n_processes (int) –

    The maximum simultaneous number of threads if use_threading is set to True, otherwise processes, used to parallelize the execution.

    By default it is set to 2.

  • chain_linearize (bool) –

    Whether to linearize the chain of execution. Otherwise, linearize the overall MDA with base class method. This last option is preferred to minimize computations in adjoint mode, while in direct mode, linearizing the chain may be cheaper.

    By default it is set to False.

  • tolerance (float) –

    The tolerance of the iterative direct coupling solver; the norm of the current residuals divided by initial residuals norm shall be lower than the tolerance to stop iterating.

    By default it is set to 1e-06.

  • linear_solver_tolerance (float) –

    The tolerance of the linear solver in the adjoint equation.

    By default it is set to 1e-12.

  • use_lu_fact (bool) –

    Whether to store a LU factorization of the matrix when using adjoint/forward differentiation. to solve faster multiple RHS problem.

    By default it is set to False.

  • grammar_type (MDODiscipline.GrammarType) –

    The type of the input and output grammars.

    By default it is set to “JSONGrammar”.

  • coupling_structure (MDOCouplingStructure | None) – The coupling structure to be used by the MDA. If None, it is created from disciplines.

  • sub_coupling_structures (Iterable[MDOCouplingStructure | None] | None) – The coupling structures to be used by the inner-MDAs. If None, they are created from the sub-disciplines.

  • log_convergence (bool) –

    Whether to log the MDA convergence, expressed in terms of normed residuals.

    By default it is set to False.

  • linear_solver (str) –

    The name of the linear solver.

    By default it is set to “DEFAULT”.

  • linear_solver_options (StrKeyMapping | None) – The options passed to the linear solver factory.

  • mdachain_parallelize_tasks (bool) –

    Whether to parallelize the parallel tasks, if any.

    By default it is set to False.

  • mdachain_parallel_options (Mapping[str, int | bool] | None) – The options of the MDOParallelChain instances, if any.

  • initialize_defaults (bool) –

    Whether to create a MDOInitializationChain to compute the eventually missing default_inputs at the first execution.

    By default it is set to False.

  • **inner_mda_options (float | int | bool | str | None) – The options of the inner-MDAs.

add_differentiated_inputs(inputs=None)[source]

Add the inputs for differentiation.

The inputs that do not represent continuous numbers are filtered out.

Parameters:

inputs (Iterable[str] | None) – The input variables against which to differentiate the outputs. If None, all the inputs of the discipline are used.

Raises:

ValueError – When ``inputs `` are not in the input grammar.

Return type:

None

add_differentiated_outputs(outputs=None)[source]

Add the outputs for differentiation.

The outputs that do not represent continuous numbers are filtered out.

Parameters:

outputs (Iterable[str] | None) – The output variables to be differentiated. If None, all the outputs of the discipline are used.

Raises:

ValueError – When ``outputs `` are not in the output grammar.

Return type:

None

execute(input_data=None)[source]

Execute the discipline.

This method executes the discipline:

Parameters:

input_data (StrKeyMapping | None) – The input data needed to execute the discipline according to the discipline input grammar. If None, use the MDODiscipline.default_inputs.

Returns:

The discipline local data after execution.

Return type:

DisciplineData

get_disciplines_in_dataflow_chain()[source]

Return the disciplines that must be shown as blocks in the XDSM.

By default, only the discipline itself is shown. This function can be differently implemented for any type of inherited discipline.

Returns:

The disciplines shown in the XDSM chain.

Return type:

list[MDODiscipline]

get_expected_dataflow()[source]

Return the expected data exchange sequence.

This method is used for the XDSM representation.

The default expected data exchange sequence is an empty list.

See also

MDOFormulation.get_expected_dataflow

Returns:

The data exchange arcs.

Return type:

list[tuple[MDODiscipline, MDODiscipline, list[str]]]

get_expected_workflow()[source]

Return the expected execution sequence.

This method is used for the XDSM representation.

The default expected execution sequence is the execution of the discipline itself.

See also

MDOFormulation.get_expected_workflow

Returns:

The expected execution sequence.

Return type:

SerialExecSequence

plot_residual_history(show=False, save=True, n_iterations=None, logscale=None, filename='', fig_size=(50.0, 10.0))[source]

Generate a plot of the residual history.

The first iteration of each new execution is marked with a red dot.

Parameters:
  • show (bool) –

    Whether to display the plot on screen.

    By default it is set to False.

  • save (bool) –

    Whether to save the plot as a PDF file.

    By default it is set to True.

  • n_iterations (int | None) – The number of iterations on the x axis. If None, use all the iterations.

  • logscale (tuple[int, int] | None) – The limits of the y axis. If empty, do not change the limits of the y axis.

  • filename (Path | str) –

    The name of the file to save the figure. If empty, use “{mda.name}_residual_history.pdf”.

    By default it is set to “”.

  • fig_size (FigSizeType) –

    The width and height of the figure in inches, e.g. (w, h).

    By default it is set to (50.0, 10.0).

Returns:

The figure, to be customized if not closed.

Return type:

None

reset_statuses_for_run()[source]

Set all the statuses to MDODiscipline.ExecutionStatus.PENDING.

Raises:

ValueError – When the discipline cannot be run because of its status.

Return type:

None

all_couplings: list[str]

The names of all the coupling variables.

assembly: JacobianAssembly
cache: BaseCache | None

The cache containing one or several executions of the discipline according to the cache policy.

coupling_structure: MDOCouplingStructure

The coupling structure to be used by the MDA.

data_processor: DataProcessor

A tool to pre- and post-process discipline data.

exec_for_lin: bool

Whether the last execution was due to a linearization.

inner_mdas: list[BaseMDA]

The ordered MDAs.

input_grammar: BaseGrammar

The input grammar.

jac: MutableMapping[str, MutableMapping[str, ndarray | csr_array | JacobianOperator]]

The Jacobians of the outputs wrt inputs.

The structure is {output: {input: matrix}}.

lin_cache_tol_fact: float

The tolerance factor to cache the Jacobian.

linear_solver: str

The name of the linear solver.

linear_solver_options: StrKeyMapping

The options of the linear solver.

linear_solver_tolerance: float

The tolerance of the linear solver in the adjoint equation.

property log_convergence: bool

Whether to log the MDA convergence.

matrix_type: JacobianAssembly.JacobianType

The type of the matrix.

property max_mda_iter: int

The maximum iterations number of the MDA algorithm.

name: str

The name of the discipline.

norm0: float | None

The reference residual, if any.

property normed_residual: float

The normed_residuals, computed from the sub-MDAs residuals.

output_grammar: BaseGrammar

The output grammar.

re_exec_policy: ReExecutionPolicy

The policy to re-execute the same discipline.

reset_history_each_run: bool

Whether to reset the history of MDA residuals before each run.

residual_history: list[float]

The history of the MDA residuals.

residual_variables: dict[str, str]

The output variables mapping to their inputs, to be considered as residuals; they shall be equal to zero.

run_solves_residuals: bool

Whether the run method shall solve the residuals.

scaling: ResidualScaling

The scaling method applied to MDA residuals for convergence monitoring.

strong_couplings: list[str]

The names of the strong coupling variables.

tolerance: float

The tolerance of the iterative direct coupling solver.

use_lu_fact: bool

Whether to store a LU factorization of the matrix.

warm_start: bool

Whether the second iteration and ongoing start from the previous solution.

Examples using MDAChain

MDAChain

MDAChain

MDAChain with independent parallel MDAs

MDAChain with independent parallel MDAs