dimod.ConstrainedQuadraticModel.add_constraint_from_model#

ConstrainedQuadraticModel.add_constraint_from_model(qm: BinaryQuadraticModel | QuadraticModel, sense: Sense | str, rhs: float | floating | integer = 0, label: Hashable | None = None, *, copy: bool = True, weight: float | None = None, penalty: str = 'linear') → Hashable[source]#

Add a constraint from a quadratic model.

Parameters:

  • qm – Quadratic model or binary quadratic model.

  • sense – One of <=, >=, ==.

  • rhs – Right-hand side of the constraint.

  • label – Label for the constraint. Must be unique. If no label is provided, then one is generated using uuid.

  • copy – If True, model qm is copied. This can be set to False to improve performance, but subsequently mutating qm can cause issues.

  • weight – Weight for a soft constraint. Must be a positive number. If None or float('inf'), the constraint is hard. In feasible solutions, all the model’s hard constraints must be met, while soft constraints might be violated to achieve overall good solutions.

  • penalty – Penalty type for a soft constraint (a constraint with its weight parameter set). Supported values are 'linear' and 'quadratic'. Ignored if weight is None. 'quadratic' is supported for a constraint with binary variables only.

Returns:

Label of the added constraint.

Examples

This example adds a constraint from the single-variable binary quadratic model x.

>>> from dimod import ConstrainedQuadraticModel, Binary
>>> cqm = ConstrainedQuadraticModel()
>>> x = Binary('x')
>>> cqm.add_constraint_from_model(x, '>=', 0, 'Min x')
'Min x'
>>> print(cqm.constraints["Min x"].to_polystring())
x >= 0.0