# 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.

### base_op

The base operation that the modifiers in this annotated operation applies to.

### modifiers

Ordered sequence of the modifiers to apply to `base_op`

. The modifiers are applied in order from lowest index to highest index.

## Methods

### control

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

Return the controlled version of itself.

Implemented as an annotated operation, see `AnnotatedOperation`

.

**Parameters**

**num_ctrl_qubits**(*int*(opens in a new tab)) – number of controls to add to gate (default:`1`

)**label**(*str*(opens in a new tab)*| None*) – ignored (used for consistency with other control methods)**ctrl_state**(*int*(opens in a new tab)*|**str*(opens in a new tab)*| None*) – The control state in decimal or as a bitstring (e.g.`'111'`

). If`None`

, use`2**num_ctrl_qubits-1`

.**annotated**(*bool*(opens in a new tab)) – ignored (used for consistency with other control methods)

**Returns**

Controlled version of the given operation.

**Return type**

### copy

### inverse

`inverse(annotated=True)`

Return the inverse version of itself.

Implemented as an annotated operation, see `AnnotatedOperation`

.

**Parameters**

**annotated** (*bool*(opens in a new tab)) – ignored (used for consistency with other inverse methods)

**Returns**

Inverse version of the given operation.

### power

`power(exponent, annotated=False)`

Raise this gate to the power of `exponent`

.

Implemented as an annotated operation, see `AnnotatedOperation`

.

**Parameters**

**exponent**(*float*(opens in a new tab)) – the power to raise the gate to**annotated**(*bool*(opens in a new tab)) – ignored (used for consistency with other power methods)

**Returns**

An operation implementing `gate^exponent`

### to_matrix

`to_matrix()`

Return a matrix representation (allowing to construct Operator).