QuadraticExpression¶

class
QuadraticExpression
(quadratic_program, coefficients)[source]¶ 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.
Attributes
Returns the lower bound and the upper bound of the quadratic expression
Returns the coefficients of the quadratic expression.
Methods
__getitem__
(key)Returns the coefficient where i, j can be a variable names or indices.
evaluate
(x)Evaluate the quadratic expression for given variables: x * Q * x.
Evaluate the gradient of the quadratic expression for given variables.
to_array
([symmetric])Returns the coefficients of the quadratic expression as array.
to_dict
([symmetric, use_name])Returns the coefficients of the quadratic expression as dictionary, either using tuples of variable names or indices as keys.