# SummedOp¶

class SummedOp(oplist, coeff=1.0, abelian=False)[source]

Bases: qiskit.opflow.list_ops.list_op.ListOp

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

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

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

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

Methods Defined Here

 add Return Operator addition of self and other, overloaded by +. collapse_summands Return Operator by simplifying duplicate operators. equals Check if other is equal to self. reduce Try collapsing list or trees of sums. to_circuit Returns the quantum circuit, representing the SummedOp. 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.

Attributes

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[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]

instance_id

Return the unique instance id.

Return type

int

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
settings

Return settings.

Return type

Dict