OperatorStateFn¶

class OperatorStateFn(primitive=None, coeff=1.0, is_measurement=False)[source]¶

A class for state functions and measurements which are defined by a density Operator, stored using an OperatorBase.

Parameters

primitive (Optional[OperatorBase]) – The OperatorBase which defines the behavior of the underlying State function.
coeff (Union[int, float, complex, ParameterExpression]) – A coefficient by which to multiply the state function
is_measurement (bool) – Whether the StateFn is a measurement operator

Attributes

`OperatorStateFn.coeff`	A coefficient by which the state function is multiplied.
`OperatorStateFn.is_measurement`	Whether the StateFn object is a measurement Operator.
`OperatorStateFn.num_qubits`	The number of qubits over which the Operator is defined.
`OperatorStateFn.primitive`	The primitive which defines the behavior of the underlying State function.

Methods

`OperatorStateFn.__mul__`(other)	Overload `*` for Operator scalar multiplication.
`OperatorStateFn.add`(other)	Return Operator addition of self and other, overloaded by `+`.
`OperatorStateFn.adjoint`()	Return a new Operator equal to the Operator’s adjoint (conjugate transpose), overloaded by `~`.
`OperatorStateFn.assign_parameters`(param_dict)	Binds scalar values to any Terra `Parameters` in the coefficients or primitives of the Operator, or substitutes one `Parameter` for another.
`OperatorStateFn.bind_parameters`(param_dict)	Same as assign_parameters, but maintained for consistency with QuantumCircuit in Terra (which has both assign_parameters and bind_parameters).
`OperatorStateFn.compose`(other)	Composition (Linear algebra-style: A@B(x) = A(B(x))) is not well defined for states in the binary function model, but is well defined for measurements.
`OperatorStateFn.equals`(other)	Evaluate Equality between Operators, overloaded by `==`.
`OperatorStateFn.eval`([front])	Evaluate the Operator’s underlying function, either on a binary string or another Operator.
`OperatorStateFn.mul`(scalar)	Returns the scalar multiplication of the Operator, overloaded by `*`, including support for Terra’s `Parameters`, which can be bound to values later (via `bind_parameters`).
`OperatorStateFn.neg`()	Return the Operator’s negation, effectively just multiplying by -1.0, overloaded by `-`.
`OperatorStateFn.power`(exponent)	Compose with Self Multiple Times, undefined for StateFns.
`OperatorStateFn.primitive_strings`()	Return a set of strings describing the primitives contained in the Operator.
`OperatorStateFn.reduce`()	Try collapsing the Operator structure, usually after some type of conversion, e.g.
`OperatorStateFn.sample`([shots, massive, …])	Sample the state function as a normalized probability distribution.
`OperatorStateFn.tensor`(other)	Return tensor product between self and other, overloaded by `^`.
`OperatorStateFn.tensorpower`(other)	Return tensor product with self multiple times, overloaded by `^`.
`OperatorStateFn.to_circuit_op`()	Return `StateFnCircuit` corresponding to this StateFn.
`OperatorStateFn.to_density_matrix`([massive])	Return numpy matrix of density operator, warn if more than 16 qubits to force the user to set massive=True if they want such a large matrix.
`OperatorStateFn.to_legacy_op`([massive])	Attempt to return the Legacy Operator representation of the Operator.
`OperatorStateFn.to_matrix`([massive])	Note: this does not return a density matrix, it returns a classical matrix containing the quantum or classical vector representing the evaluation of the state function on each binary basis state.
`OperatorStateFn.to_matrix_op`([massive])	Return a MatrixOp for this operator.
`OperatorStateFn.traverse`(convert_fn[, coeff])	Apply the convert_fn to the internal primitive if the primitive is an Operator (as in the case of `OperatorStateFn`).
`OperatorStateFn.__mul__`(other)	Overload `*` for Operator scalar multiplication.