OM Tools Group¶

class omtools.core.group.Group(**kwargs)¶

The omtools.Group class builds openmdao.Component objects from Python-like expressions and adds their corresponding subsystems by constructing stock openmdao.Component objects.

In self.setup, first, the user declares inputs, writes expressions, and registers outputs. After self.setup runs, self builds a Directed Acyclic Graph (DAG) from registered outputs, analyzes the DAG to determine execution order, and adds the appropriate subsystems.

In addition to supporting an expression-based style of defining a subsystem, omtools.Group also supports adding a subystem defined using a subclass of omtools.Group or openmdao.System.

The omtools.Group class only allows for expressions that define explicit relationships. For defining models that use implicit relationships and defining residuals, see omtools.ImplicitGroup.

add_subsystem(name: str, subsys: openmdao.core.system.System, promotes: Optional[collections.abc.Iterable] = None, promotes_inputs: Optional[collections.abc.Iterable] = None, promotes_outputs: Optional[collections.abc.Iterable] = None)¶

Add a subsystem to the Group.

self.add_subsystem call must be preceded by a call to self.register_output for each of the subsystem’s inputs, and followed by self.declare_input for each of the subsystem’s outputs.

Parameters

name: str: Name of subsystem
subsys: System: Subsystem to add to Group
promotes: Iterable: Variables to promote
promotes_inputs: Iterable: Inputs to promote
promotes_outputs: Iterable: Outputs to promote

Returns

System: Subsystem to add to Group

create_group(name: str)¶

Create a Group object and add as a subsystem, promoting all inputs and outputs. For use in with contexts. NOTE: Only use if planning to promote all varaibales within child Group object.

Parameters

name: str: Name of new child Group object

Returns

Group: Child Group object whosevariables are all promoted

create_implicit_output(name: str, shape: Tuple[int] = (1), val=1) → omtools.core.implicit_output.ImplicitOutput ¶

Create a value that is computed implicitly

Parameters

name: str: Name of variable in OpenMDAO to be computed by an ImplicitComponent
shape: Tuple[int]: Shape of variable

Returns

ImplicitOutput: An object to use in expressions

create_indep_var(name: str, shape: Tuple[int] = (1), val=1, dv: bool = False) → omtools.core.indep.Indep ¶

Create a value that is constant during model evaluation

Parameters

name: str: Name of variable in OpenMDAO to be computed by ExplicitComponent objects connected in a cycle, or by an ExplicitComponent that concatenates variables
shape: Tuple[int]: Shape of variable
val: Number or ndarray: Value for variable during first model evaluation
dv: bool: Flag to set design variable

Returns

Indep: An object to use in expressions

create_output(name: str, shape: Tuple[int] = (1), val=1) → omtools.core.explicit_output.ExplicitOutput ¶

Create a value that is computed explicitly

Parameters

name: str: Name of variable in OpenMDAO to be computed by ExplicitComponent objects connected in a cycle, or by an ExplicitComponent that concatenates variables
shape: Tuple[int]: Shape of variable

Returns

ExplicitOutput: An object to use in expressions

declare_input(name: str, shape: Tuple[int] = (1), val=1) → omtools.core.input.Input ¶

Declare an input to use in an expression.

An input can be an output of a child System. If the user declares an input that is computed by a child System, then the call to self.declare_input must appear after the call to self.add_subsystem.

Parameters

name: str: Name of variable in OpenMDAO to be used as an input in generated Component objects
shape: Tuple[int]: Shape of variable
val: Number or ndarray: Default value for variable

Returns

Input: An object to use in expressions

initialize(*args, **kwargs)¶: User defined method to set options

register_output(name: str, expr: omtools.core.explicit_output.ExplicitOutput) → omtools.core.explicit_output.ExplicitOutput ¶

Register expr as an output of the Group. When adding subsystems, each of the subsystem’s inputs requires a call to register_output prior to the call to add_subsystem.

Parameters

name: str: Name of variable in OpenMDAO
expr: Variable: Variable that computes output

Returns

Variable: Variable that computes output

setup()¶: User defined method to define expressions and add subsystems for model execution