OperatorStateFn¶

class
OperatorStateFn
(primitive=None, coeff=1.0, is_measurement=False)[source]¶ Bases:
qiskit.aqua.operators.state_fns.state_fn.StateFn
A class for state functions and measurements which are defined by a density Operator, stored using an
OperatorBase
. Parameters
primitive (
Optional
[OperatorBase
]) – TheOperatorBase
which defines the behavior of the underlying State function.coeff (
Union
[int
,float
,complex
,ParameterExpression
]) – A coefficient by which to multiply the state functionis_measurement (
bool
) – Whether the StateFn is a measurement operator
Methods
Return Operator addition of self and other, overloaded by
+
.Return a new Operator equal to the Operator’s adjoint (conjugate transpose), overloaded by
~
.Binds scalar values to any Terra
Parameters
in the coefficients or primitives of the Operator, or substitutes oneParameter
for another.Same as assign_parameters, but maintained for consistency with QuantumCircuit in Terra (which has both assign_parameters and bind_parameters).
Composition (Linear algebrastyle: A@B(x) = A(B(x))) is not well defined for states in the binary function model, but is well defined for measurements.
Evaluate Equality between Operators, overloaded by
==
.Evaluate the Operator’s underlying function, either on a binary string or another Operator.
Returns the scalar multiplication of the Operator, overloaded by
*
, including support for Terra’sParameters
, which can be bound to values later (viabind_parameters
).Return the Operator’s negation, effectively just multiplying by 1.0, overloaded by

.Permute the qubits of the state function.
Compose with Self Multiple Times, undefined for StateFns.
Return a set of strings describing the primitives contained in the Operator.
Try collapsing the Operator structure, usually after some type of conversion, e.g.
Sample the state function as a normalized probability distribution.
Return tensor product between self and other, overloaded by
^
.Return tensor product with self multiple times, overloaded by
^
.Return
StateFnCircuit
corresponding to this StateFn.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.
Attempt to return the Legacy Operator representation of the Operator.
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.
Return a MatrixOp for this operator.
Apply the convert_fn to the internal primitive if the primitive is an Operator (as in the case of
OperatorStateFn
).Attributes

ENABLE_DEPRECATION
= True¶

INDENTATION
= ' '¶

coeff
¶ A coefficient by which the state function is multiplied.
 Return type
Union
[int
,float
,complex
,ParameterExpression
]

is_measurement
¶ Whether the StateFn object is a measurement Operator.
 Return type
bool

num_qubits
¶  Return type
int

parameters
¶

primitive
¶ The primitive which defines the behavior of the underlying State function.