QuboTranslator

Utility class for converting between dense QUBO matrices and symbolic models.

QuboTranslator provides methods to: - Convert a NumPy-style QUBO matrix into a symbolic Model - Convert a Model (with quadratic objective) into a dense QUBO matrix

These conversions are especially useful when interacting with external solvers or libraries that operate on matrix-based problem definitions.

Examples:

>>> import numpy as np
>>> from luna_quantum.translator import QuboTranslator, Vtype
>>> q = np.array([[1.0, -1.0], [-1.0, 2.0]])

Create a model from a matrix:

>>> model = QuboTranslator.to_aq(
...     q, offset=4.2, name="qubo_model", vtype=Vtype.Binary
... )

Convert it back to a dense matrix:

>>> recovered = QuboTranslator.from_aq(model)
>>> assert np.allclose(q, recovered.matrix)

from_aq staticmethod

from_aq(model: Model) -> Qubo

Convert a symbolic model to a dense QUBO matrix representation.

Parameters:

Name	Type	Description	Default
model	Model	The symbolic model to convert. The objective must be quadratic-only and unconstrained.	required

Returns:

Type	Description
Qubo	An object representing a QUBO with information additional to the square NumPy array representing the QUBO matrix derived from the model's objective. This object also includes the variable_ordering as well as the offset of the original model.

Raises:

Type	Description
TranslationError	Generally if the translation fails. Might be specified by one of the four following errors.
ModelNotQuadraticError	If the objective contains higher-order (non-quadratic) terms.
ModelNotUnconstrainedError	If the model contains any constraints.
ModelSenseNotMinimizeError	If the model's optimization sense is 'maximize'.
ModelVtypeError	If the model contains different vtypes or vtypes other than binary and spin.

to_aq staticmethod

to_aq(
    qubo: NDArray,
    *,
    offset: float | None = ...,
    variable_names: list[str] | None = ...,
    name: str | None = ...,
    vtype: Vtype | None = ...,
) -> Model

Convert a dense QUBO matrix into a symbolic Model.

Parameters:

Name	Type	Description	Default
qubo	NDArray	A square 2D NumPy array representing the QUBO matrix. Diagonal entries correspond to linear coefficients; off-diagonal entries represent pairwise quadratic terms.	required
name	str	An optional name to assign to the resulting model.	...
vtype	Vtype	The variable type to assign to all variables (e.g. Binary, Spin).	...

Returns:

Type	Description
Model	A symbolic model representing the given QUBO structure.

Raises:

Type	Description
TranslationError	Generally if the translation fails. Might be specified by the following error.
VariableNamesError	If a list of variable names is provided but contains duplicates or has an incorrect length.