ComposedOp

class ComposedOp(oplist, coeff=1.0, abelian=False)

Bases: qiskit.aqua.operators.list_ops.list_op.ListOp

A class for lazily representing compositions of Operators. Often Operators cannot be efficiently composed with one another, but may be manipulated further so that they can be composed later. This class holds logic to indicate that the Operators in oplist are meant to be composed, and therefore if they reach a point in which they can be, such as after conversion to QuantumCircuits or matrices, they can be reduced by composition.

Parameters

• oplist (List[OperatorBase]) – The Operators being composed.

• coeff (Union[int, float, complex, ParameterExpression]) – A coefficient multiplying the operator

• abelian (bool) – Indicates whether the Operators in oplist are known to mutually commute.

Methods

add	Return Operator addition of self and other, overloaded by +.
adjoint	Return a new Operator equal to the Operator’s adjoint (conjugate transpose), overloaded by ~.
assign_parameters	Binds scalar values to any Terra Parameters in the coefficients or primitives of the Operator, or substitutes one Parameter for another.
bind_parameters	Same as assign_parameters, but maintained for consistency with QuantumCircuit in Terra (which has both assign_parameters and bind_parameters).
compose	Return Operator Composition between self and other (linear algebra-style: A@B(x) = A(B(x))), overloaded by @.
equals	Evaluate Equality between Operators, overloaded by ==.
eval	Evaluate the Operator’s underlying function, either on a binary string or another Operator.
exp_i	Return an OperatorBase equivalent to an exponentiation of self * -i, e^(-i*op).
log_i	Return a MatrixOp equivalent to log(H)/-i for this operator H.
mul	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).
neg	Return the Operator’s negation, effectively just multiplying by -1.0, overloaded by -.
non_distributive_reduce	Reduce without attempting to expand all distributive compositions.
permute	Permute the qubits of the operator.
power	Return Operator composed with self multiple times, overloaded by **.
primitive_strings	Return a set of strings describing the primitives contained in the Operator.
reduce	Try collapsing the Operator structure, usually after some type of conversion, e.g.
tensor	Return tensor product between self and other, overloaded by ^.
tensorpower	Return tensor product with self multiple times, overloaded by ^.
to_circuit	Returns the quantum circuit, representing the composed operator.
to_circuit_op	Returns an equivalent Operator composed of only QuantumCircuit-based primitives, such as CircuitOp and CircuitStateFn.
to_legacy_op	Attempt to return the Legacy Operator representation of the Operator.
to_matrix	Return NumPy representation of the Operator.
to_matrix_op	Returns an equivalent Operator composed of only NumPy-based primitives, such as MatrixOp and VectorStateFn.
to_pauli_op	Returns an equivalent Operator composed of only Pauli-based primitives, such as PauliOp.
to_spmatrix	Returns SciPy sparse matrix representation of the Operator.
traverse	Apply the convert_fn to each node in the oplist.

Attributes

ENABLE_DEPRECATION = True

INDENTATION = ' '

abelian

Whether the Operators in oplist are known to commute with one another.

Return type

bool

Returns

A bool indicating whether the oplist is Abelian.

coeff

The scalar coefficient multiplying the Operator.

Return type

Union[int, float, complex, ParameterExpression]

Returns

The coefficient.

combo_fn

The function defining how to combine oplist (or Numbers, or NumPy arrays) to produce the Operator’s underlying function. For example, SummedOp’s combination function is to add all of the Operators in oplist.

Return type

Callable

Returns

The combination function.

distributive

Return type

bool

grad_combo_fn

The gradient of combo_fn.

Return type

Optional[Callable]

num_qubits

Return type

int

oplist

The list of OperatorBases defining the underlying function of this Operator.

Return type

List[OperatorBase]

Returns

The Operators defining the ListOp

parameters