QuadraticExpression

class QuadraticExpression(quadratic_program, coefficients)

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.

Attributes

QuadraticExpression.coefficients	Returns the coefficients of the quadratic expression.
QuadraticExpression.quadratic_program	Returns the parent QuadraticProgram.

Methods

QuadraticExpression.__getitem__(key)	Returns the coefficient where i, j can be a variable names or indices.
QuadraticExpression.evaluate(x)	Evaluate the quadratic expression for given variables: x * Q * x.
QuadraticExpression.to_array([symmetric])	Returns the coefficients of the quadratic expression as array.
QuadraticExpression.to_dict([symmetric, …])	Returns the coefficients of the quadratic expression as dictionary, either using tuples of variable names or indices as keys.