# ListOp¶

class ListOp(oplist, combo_fn=<function ListOp.<lambda>>, coeff=1.0, abelian=False, grad_combo_fn=None)[소스]

기반 클래스: qiskit.aqua.operators.operator_base.OperatorBase

A Class for manipulating List Operators, and parent class to SummedOp, ComposedOp, and TensoredOp.

List Operators are classes for storing and manipulating lists of Operators, State functions, or Measurements, and include some rule or combo_fn defining how the Operator functions of the list constituents should be combined to form to cumulative Operator function of the ListOp. For example, a SummedOp has an addition-based combo_fn, so once the Operators in its list are evaluated against some bitstring to produce a list of results, we know to add up those results to produce the final result of the SummedOp’s evaluation. In theory, this combo_fn can be any function over classical complex values, but for convenience we’ve chosen for them to be defined over NumPy arrays and values. This way, large numbers of evaluations, such as after calling to_matrix on the list constituents, can be efficiently combined. While the combination function is defined over classical values, it should be understood as the operation by which each Operators’ underlying function is combined to form the underlying Operator function of the ListOp. In this way, the ListOps are the basis for constructing large and sophisticated Operators, State Functions, and Measurements in Aqua.

The base ListOp class is particularly interesting, as its combo_fn is “the identity list Operation”. Meaning, if we understand the combo_fn as a function from a list of complex values to some output, one such function is returning the list as-is. This is powerful for constructing compact hierarchical Operators which return many measurements in multiple dimensional lists.

매개변수
• oplist (List[OperatorBase]) – The list of OperatorBases defining this Operator’s underlying function.

• combo_fn (callable) – The recombination function to combine classical results of the oplist Operators’ eval functions (e.g. sum).

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

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

• grad_combo_fn (Optional[Callable]) – The gradient of recombination function. If None, the gradient will be computed automatically.

• that the default "recombination function" lambda above is essentially the (Note) –

• - it accepts the list of values (identity) –

• returns them in a list. (and) –

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 -. 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_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.

반환 형식

bool

반환값

A bool indicating whether the oplist is Abelian.

coeff

The scalar coefficient multiplying the Operator.

반환 형식

Union[int, float, complex, ParameterExpression]

반환값

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.

반환 형식

Callable

반환값

The combination function.

distributive

Indicates whether the ListOp or subclass is distributive under composition. ListOp and SummedOp are, meaning that (opv @ op) = (opv[0] @ op + opv[1] @ op) (using plus for SummedOp, list for ListOp, etc.), while ComposedOp and TensoredOp do not behave this way.

반환 형식

bool

반환값

A bool indicating whether the ListOp is distributive under composition.

grad_combo_fn

The gradient of combo_fn.

반환 형식

Optional[Callable]

num_qubits
반환 형식

int

oplist

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

반환 형식

List[OperatorBase]

반환값

The Operators defining the ListOp

parameters