SummedOp
class SummedOp(oplist, coeff=1.0, abelian=False)
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 inoplistare known to mutually commute.
Methods Defined Here
add
SummedOp.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).
Return type
Returns
A SummedOp equivalent to the sum of self and other.
collapse_summands
SummedOp.collapse_summands()
Return Operator by simplifying duplicate operators.
E.g., SummedOp([2 * X ^ Y, X ^ Y]).collapse_summands() -> SummedOp([3 * X ^ Y]).
Return type
Returns
A simplified SummedOp equivalent to self.
equals
SummedOp.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.
Return type
bool
Returns
True, if other and self are equal, otherwise False.
Examples
>>> from qiskit.opflow import X, Z
>>> 2 * X == X + X
True
>>> X + Z == Z + X
Truereduce
SummedOp.reduce()
Try collapsing list or trees of sums.
Tries to sum up duplicate operators and reduces the operators in the sum.
Return type
Returns
A collapsed version of self, if possible.
to_circuit
SummedOp.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.
Return type
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**)****.** –
to_matrix_op
SummedOp.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
SummedOp.to_pauli_op(massive=False)
Returns an equivalent Operator composed of only Pauli-based primitives, such as PauliOp.
Return type
Attributes
INDENTATION
Default value: ' '
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.
coeffs
Return a list of the coefficients of the operators listed. Raises exception for nested Listops.
Return type
List[Union[complex, ParameterExpression]]
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