QuadraticExpression

class QuadraticExpression(quadratic_program, coefficients)

Bases: qiskit.optimization.problems.quadratic_program_element.QuadraticProgramElement

Representation of a quadratic expression by its coefficients.

Creates a new quadratic expression.

The quadratic expression can be defined via an array, a list, a sparse matrix, or a dictionary that uses variable names or indices as keys and stores the values internally as a dok_matrix. We stores values in a compressed way, i.e., values at symmetric positions are summed up in the upper triangle. For example, {(0, 1): 1, (1, 0): 2} -> {(0, 1): 3}.

Parameters

• quadratic_program (Any) – The parent QuadraticProgram.

• coefficients (Union[ndarray, spmatrix, List[List[float]], Dict[Tuple[Union[int, str], Union[int, str]], float]]) – The (sparse) representation of the coefficients.

Methods

evaluate	Evaluate the quadratic expression for given variables: x * Q * x.
evaluate_gradient	Evaluate the gradient of the quadratic expression for given variables.
to_array	Returns the coefficients of the quadratic expression as array.
to_dict	Returns the coefficients of the quadratic expression as dictionary, either using tuples of variable names or indices as keys.

Attributes

coefficients

Returns the coefficients of the quadratic expression.

Return type

dok_matrix

Returns

The coefficients of the quadratic expression.

quadratic_program

Returns the parent QuadraticProgram.

Return type

Any

Returns

The parent QuadraticProgram.