OutputVariable

OutputVariable

Bases: Variable

Variable to represents the output of a fuzzy logic controller.

During the activation of a rule block, the activated terms of each rule are aggregated in the fuzzy output, which represents a fuzzy set hereinafter referred to as \(\tilde{y}\).

The defuzzification of \(\tilde{y}\) converts the fuzzy output value \(\tilde{y}\) into a crisp output value \(y\), which is stored as the value of this variable.

related

• fuzzylite.variable.Variable
• fuzzylite.variable.InputVariable
• fuzzylite.term.Term
• fuzzylite.rule.RuleBlock
• fuzzylite.norm.SNorm

Attributes

aggregation property writable

aggregation: SNorm | None

Get/Set the aggregation operator.

Getter

Returns:

Type	Description
SNorm | None	aggregation operator.

Setter

Parameters:

Name	Type	Description	Default
value	SNorm	aggregation operator	required

default_value instance-attribute

default_value = default_value

defuzzifier instance-attribute

defuzzifier = defuzzifier

fuzzy instance-attribute

fuzzy = Aggregated(name=name, minimum=minimum, maximum=maximum, aggregation=aggregation)

lock_previous instance-attribute

lock_previous = lock_previous

maximum property writable

maximum: float

Get/Set the maximum value of the range of the output variable.

Getter

Returns:

Type	Description
float	maximum value of the range of the output variable.

Setter

Parameters:

Name	Type	Description	Default
value	float	maximum value of the output variable.	required

minimum property writable

minimum: float

Get/Set the minimum value of the range of the output variable.

Getter

Returns:

Type	Description
float	minimum value of the range of the output variable.

Setter

Parameters:

Name	Type	Description	Default
value	float	minimum value of the output variable.	required

previous_value instance-attribute

previous_value = nan

Functions

__init__

__init__(
    name: str = "",
    description: str = "",
    enabled: bool = True,
    minimum: float = -inf,
    maximum: float = inf,
    lock_range: bool = False,
    lock_previous: bool = False,
    default_value: float = nan,
    aggregation: SNorm | None = None,
    defuzzifier: Defuzzifier | None = None,
    terms: Iterable[Term] | None = None,
) -> None

Constructor.

Parameters:

Name	Type	Description	Default
name	str	name of the variable	''
description	str	description of the variable	''
enabled	bool	enable the variable	True
minimum	float	minimum value of the variable	-inf
maximum	float	maximum value of the variable	inf
lock_range	bool	lock the value to the range of the variable	False
lock_previous	bool	lock the previous value of the output variable	False
default_value	float	default value of the output variable	nan
aggregation	SNorm | None	aggregation operator	None
defuzzifier	Defuzzifier | None	defuzzifier of the output variable	None
terms	Iterable[Term] | None	list of terms.	None

__repr__

__repr__() -> str

Return the code to construct the output variable in Python.

Returns:

Type	Description
str	code to construct the output variable in Python.

__str__

__str__() -> str

Return the code to construct the output variable in the FuzzyLite Language.

Returns:

Type	Description
str	code to construct the output variable in the FuzzyLite Language.

clear

clear() -> None

Clear the output variable.

defuzzify

defuzzify() -> None

Defuzzify the output variable and store the output value and the previous output value.

The final value \(y\) depends on the following cascade of properties in order of precedence expressed in the FuzzyLite Language:

• lock-previous: boolean: when the output value is not finite (ie, nan or inf) and lock-previous: true, then the output value is replaced with the value defuzzified in the previous iteration.

• default: scalar: when the output value is (still) not finite and the default value is not nan, then the output value is replaced with the default value.

• lock-range: boolean: when lock-range: true, the output value is clipped to the range of the variable.

fuzzy_value

fuzzy_value() -> Array[str_]

Return the current fuzzy output value.

Returns:

Type	Description
Array[str_]	current fuzzy output value.