SummedOp
class qiskit.opflow.list_ops.SummedOp(oplist, coeff=1.0, abelian=False)
Bases: ListOp
Deprecated: 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.
The class qiskit.opflow.list_ops.summed_op.SummedOp is deprecated as of qiskit-terra 0.24.0. It will be removed no earlier than 3 months after the release date. For code migration guidelines, visit https://qisk.it/opflow_migration.
Parameters
- oplist (List[OperatorBase]) – The Operators being summed.
- coeff (complex |ParameterExpression) – A coefficient multiplying the operator
- abelian (bool) – Indicates whether the Operators in
oplistare known to mutually commute.
Attributes
INDENTATION
Default value: ' '
abelian
Whether the Operators in oplist are known to commute with one another.
Returns
A bool indicating whether the oplist is Abelian.
coeff
The scalar coefficient multiplying the Operator.
Returns
The coefficient.
coeffs
Return a list of the coefficients of the operators listed. Raises exception for nested Listops.
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.
Returns
The combination function.
distributive
grad_combo_fn
The gradient of combo_fn.
instance_id
Return the unique instance id.
num_qubits
oplist
The list of OperatorBases defining the underlying function of this Operator.
Returns
The Operators defining the ListOp
parameters
settings
Return settings.
Methods
add
add(other)
Return Operator addition of self and other, overloaded by +.
This appends other to self.oplist without checking other is already included or not. If you want to simplify them, please use simplify().
Parameters
other (OperatorBase) – An OperatorBase with the same number of qubits as self, and in the same ‘Operator’, ‘State function’, or ‘Measurement’ category as self (i.e. the same type of underlying function).
Returns
A SummedOp equivalent to the sum of self and other.
Return type
collapse_summands
collapse_summands()
Return Operator by simplifying duplicate operators.
E.g., SummedOp([2 * X ^ Y, X ^ Y]).collapse_summands() -> SummedOp([3 * X ^ Y]).
Returns
A simplified SummedOp equivalent to self.
Return type
equals
equals(other)
Check if other is equal to self.
This is not a mathematical check for equality. If self and other implement the same operation but differ in the representation (e.g. different type of summands) equals will evaluate to False.
Parameters
other (OperatorBase) – The other operator to check for equality.
Returns
True, if other and self are equal, otherwise False.
Return type
Examples
>>> from qiskit.opflow import X, Z
>>> 2 * X == X + X
True
>>> X + Z == Z + X
Truereduce
reduce()
Try collapsing list or trees of sums.
Tries to sum up duplicate operators and reduces the operators in the sum.
Returns
A collapsed version of self, if possible.
Return type
to_circuit
to_circuit()
Returns the quantum circuit, representing the SummedOp. In the first step, the SummedOp is converted to MatrixOp. This is straightforward for most operators, but it is not supported for operators containing parameterized PrimitiveOps (in that case, OpflowError is raised). In the next step, the MatrixOp representation of SummedOp is converted to circuit. In most cases, if the summands themselves are unitary operators, the SummedOp itself is non-unitary and can not be converted to circuit. In that case, ExtensionError is raised in the underlying modules.
Returns
The circuit representation of the summed operator.
Raises
- OpflowError – if SummedOp can not be converted to MatrixOp (e.g. SummedOp is composed of
- parameterized PrimitiveOps**)****.** –
Return type
to_matrix_op
to_matrix_op(massive=False)
Returns an equivalent Operator composed of only NumPy-based primitives, such as MatrixOp and VectorStateFn.
Return type
to_pauli_op
to_pauli_op(massive=False)
Returns an equivalent Operator composed of only Pauli-based primitives, such as PauliOp.
Return type