Constraint¶

class Constraint¶

Constraint class representing equality or inequality conditions on polynomial expressions.

Methods

`__init__`	Construct a constraint from bounds and a penalty polynomial.
`is_satisfied`	Check whether the constraint is satisfied.

Attributes

`conditional`	Constraint condition as `(left, op, right)` tuple.
`label`	Constraint label used for identification.
`penalty`	Penalty polynomial associated with this constraint.
`weight`	Constraint weight.

__add__(self, arg: Constraint, /) → ConstraintList¶

Combine two constraints into a ConstraintList.

Parameters:: arg (Constraint)
Returns:: A new ConstraintList containing both constraints.
Return type:: ConstraintList

__eq__(self, arg: object, /) → bool¶

Tell whether the two constraints have the same condition, the same weight, and the same label.

Parameters:: arg (object)
Return type:: bool

__imul__(self, arg: float, /) → Constraint¶

Multiply the weight of the constraint by the coefficient.

Parameters:: arg (float)
Return type:: Constraint

__init__( self, left: Poly, bounds: tuple[float | None, float | None], penalty: Poly, label: str = '', threshold: float = 0.0, ) → None¶

__init__(self, left: Poly, eq: float, penalty: Poly, label: str = '', threshold: float = 0.0) → None

__init__(self, left: Poly, le: float, penalty: Poly, label: str = '', threshold: float = 0.0) → None

__init__(self, left: Poly, ge: float, penalty: Poly, label: str = '', threshold: float = 0.0) → None

Construct a constraint from bounds and a penalty polynomial.

Overload 1.

Args:

left (amplify.Poly): Left-hand side polynomial.
bounds (tuple[float | None, float | None]): Bounds as (lower, upper). At least one must be specified.
penalty (amplify.Poly): Penalty polynomial.
label (str): Constraint label. Defaults to ''.
threshold (float): Satisfaction threshold. Defaults to 0.0.

Overload 2.

Args:

left (amplify.Poly): Left-hand side polynomial.
eq (float): Right-hand side value for equality.
penalty (amplify.Poly): Penalty polynomial.
label (str): Constraint label. Defaults to ''.
threshold (float): Satisfaction threshold. Defaults to 0.0.

Overload 3.

Args:

left (amplify.Poly): Left-hand side polynomial.
le (float): Upper bound value.
penalty (amplify.Poly): Penalty polynomial.
label (str): Constraint label. Defaults to ''.
threshold (float): Satisfaction threshold. Defaults to 0.0.

Overload 4.

Args:

left (amplify.Poly): Left-hand side polynomial.
ge (float): Lower bound value.
penalty (amplify.Poly): Penalty polynomial.
label (str): Constraint label. Defaults to ''.
threshold (float): Satisfaction threshold. Defaults to 0.0.

__itruediv__(self, arg: float, /) → Constraint¶

Divide the weight of the constraint by the coefficient.

Parameters:: arg (float)
Return type:: Constraint

__mul__(self, arg: float, /) → Constraint¶

Give a new constraint whose weight is the weight of this one times the coefficient.

Parameters:: arg (float)
Return type:: Constraint

__ne__(self, arg: object, /) → bool¶

Tell whether the two constraints differ. This is the negation of ==.

Parameters:: arg (object)
Return type:: bool

__radd__(self, arg: int, /) → Constraint¶

Parameters:: arg (int)
Return type:: Constraint

__repr__(self) → str¶

Return type:: str

__rmul__(self, arg: float, /) → Constraint¶

Give a new constraint whose weight is the weight of this one times the coefficient.

Parameters:: arg (float)
Return type:: Constraint

__str__(self) → str¶

Return type:: str

__truediv__(self, arg: float, /) → Constraint¶

Give a new constraint whose weight is the weight of this one divided by the coefficient.

Parameters:: arg (float)
Return type:: Constraint

is_satisfied(self, values: Values) → bool¶

is_satisfied( self, mapping: Mapping[Poly, float | int] | Mapping[Variable, float | int], ) → bool

Check whether the constraint is satisfied.

Overload 1.

Args:

values (amplify.Values): Values for variables, typically result.best.values.

Returns:

bool: True if the condition is satisfied.

Overload 2.

Args:

mapping (collections.abc.Mapping[amplify.Poly, float | int] | collections.abc.Mapping[amplify.Variable, float | int]): Mapping from variable to numeric value.

Returns:

bool: True if the condition is satisfied.

property conditional¶

Constraint condition as (left, op, right) tuple.

Returns:: Left polynomial, operator literal, and right-hand side value(s).
Return type:: tuple[Poly, Literal[‘EQ’, ‘GE’, ‘GT’, ‘LE’, ‘LT’, ‘BW’], float | tuple[float, float]]

property label¶

Constraint label used for identification.

Return type:: str

property penalty¶

Penalty polynomial associated with this constraint.

The penalty function is zero when the constraint holds and positive otherwise. An inequality over a left-hand side whose range is unknown has no exact penalty function, so it needs a relaxation formulation.

Returns:

Penalty expression used for this constraint.

The polynomial that the conversion adds to the objective function.

Return type:

Poly

Raises:

RuntimeError – The constraint is an inequality, the range of its left-hand side is unknown, and the penalty formulation is not a relaxation.

property weight¶

Constraint weight.

Larger values enforce this constraint more strongly when penalty methods are used. The setter refuses a negative value.

Return type:: float
Raises:: ValueError – The setter received a negative weight.