AnnotatedOperation

class qiskit.circuit.AnnotatedOperation(base_op, modifiers)

Bases: Operation

Annotated operation.

Create a new AnnotatedOperation.

An “annotated operation” allows to add a list of modifiers to the “base” operation. For now, the only supported modifiers are of types InverseModifier, ControlModifier and PowerModifier.

An annotated operation can be viewed as an extension of ControlledGate (which also allows adding control to the base operation). However, an important difference is that the circuit definition of an annotated operation is not constructed when the operation is declared, and instead happens during transpilation, specifically during the HighLevelSynthesis transpiler pass.

An annotated operation can be also viewed as a “higher-level” or “more abstract” object that can be added to a quantum circuit. This enables writing transpiler optimization passes that make use of this higher-level representation, for instance removing a gate that is immediately followed by its inverse.

Parameters

base_op (Operation) – base operation being modified
modifiers (Union[Modifier, List[Modifier]]) – ordered list of modifiers. Supported modifiers include InverseModifier, ControlModifier and PowerModifier.

Examples:

op1 = AnnotatedOperation(SGate(), [InverseModifier(), ControlModifier(2)])
 
op2_inner = AnnotatedGate(SGate(), InverseModifier())
op2 = AnnotatedGate(op2_inner, ControlModifier(2))

Both op1 and op2 are semantically equivalent to an SGate() which is first inverted and then controlled by 2 qubits.

Attributes

name

Unique string identifier for operation type.

num_clbits

Number of classical bits.

num_qubits

Number of qubits.

Methods

control

control(num_ctrl_qubits=1, label=None, ctrl_state=None, annotated=True)

GitHub

Return the controlled version of itself.

Implemented as an annotated operation, see AnnotatedOperation.

Parameters

num_ctrl_qubits (int) – number of controls to add to gate (default: 1)
label (str | None) – ignored (used for consistency with other control methods)
ctrl_state (int |str | None) – The control state in decimal or as a bitstring (e.g. '111'). If None, use 2**num_ctrl_qubits-1.
annotated (bool) – ignored (used for consistency with other control methods)